# Espressif Audio Development Guide

[中文]

This is the documentation for Espressif Audio Development Framework (ADF).

Get Started | API Reference | Design Guide

## Get Started

This document is intended to help users set up the software environment for the development of audio applications using hardware based on the ESP32 family of chips by Espressif. After that, a simple example will show you how to use ESP-ADF (Espressif Audio Development Framework).

### Development Board Overview

For easier start with ESP-ADF, Espressif designed ESP32, ESP32-S2, and ESP32-S3 based development boards intended for audio applications. Click the links below to learn more about the available boards.

- ESP32-LyraT

- ESP32-LyraT-Mini

- ESP32-LyraTD-MSC

- ESP32-S2-Kaluga-1

- ESP32-Korvo-DU1906

- ESP32-S3-Korvo-2

- ESP32-C3-Lyra

If you do not have any of the above boards, you can still use ESP-ADF for the ESP32 and ESP32-S2 based audio applications. For this, your board needs to have a compatible audio codec or DSP chip; alternatively, you can develop a driver to support communication with your specific chip.

### About ESP-ADF

The ESP-ADF is available as a set of components to extend the functionality already delivered by the ESP-IDF (Espressif IoT Development Framework).

To use ESP-ADF you need set up the ESP-IDF first, and this is described in the next section.

Note

ESP-ADF provides support for specific ESP-IDF versions. If your have already set up another version, please switch to a supported ESP-IDF version, or you may not be able to compile ESP-ADF applications. In addition, the python version needs to be between 3.7 and 3.11.

### Quick Start

This section provides quick steps to run a simple ADF sample project on an ESP device for experienced users. For beginners, please go through the complete steps from Step 1. Set up ESP-IDF to Step 9. Monitor to build a project.

Note

If you encounter issues in the following steps, you could refer to the complete steps from Step 1. Set up ESP-IDF to Step 9. Monitor or describe them in GitHub Issues or ESP Forum.

#### Linux and macOS

The operating environment below is on Linux Ubuntu 18.04 and above.

1. Download the full ESP-ADF repository from GitHub by running:

       git clone --recursive https://github.com/espressif/esp-adf.git

   For users located in China, it is faster to download from Gitee:

       git clone --recursive https://gitee.com/EspressifSystems/esp-adf.git

2. Configure the `$ESP-IDF` and `$ESP-ADF` compilation environment by running:

       cd esp-adf
       ./install.sh
       . ./export.sh

3. After completing the above environment variable configuration, you can compile the ADF sample project `$ADF_PATH/examples/get-started/play_mp3_control`. Switch to the project’s directory, compile, and flash it onto your ESP device by running the following command. Then, you will see the serial port of the routine is printed.

>     cd $ADF_PATH/examples/get-started/play_mp3_control
>     idf.py build flash monitor

#### Windows

1. Download the full ESP-ADF repository from GitHub by running:

       git clone --recursive https://github.com/espressif/esp-adf.git

   For users located in China, it is faster to download from Gitee:

       git clone --recursive https://gitee.com/EspressifSystems/esp-adf.git

2. Install the `$ESP-IDF` compilation environment in the command prompt window:

       cd esp-adf
       .\install.bat

   Or first download the full ESP-IDF Windows Installer from ESP-IDF Windows Installer (Please download the ESP-IDF versions supported by ESP-ADF). And then turn off the antivirus software (Because it may prevent the installation as the software writes the Windows system regedit) and install the downloaded file. After the installation is complete, open the ESP-IDF CMD shortcut icon on the desktop, the script will automatically help you download submodules, and set environment variables such as `IDF_PATH`.

3. Set the `ADF_PATH` by running the following commands:

       .\export.bat
       echo %ADF_PATH%

4. If your `ADF_PATH` variable prints correctly, it’s time to compile the ADF routines:

       cd %ADF_PATH%\examples\get-started\play_mp3_control
       idf.py build flash monitor

### Installation Step by Step

This is a detailed roadmap to walk you through the installation process.

#### Setting up Development Environment

- Step 1. Set up ESP-IDF for Windows, Linux or Mac OS

- Step 2. Get ESP-ADF

- Step 3. Set up the environment

#### Creating Your First Project

- Step 4. Start a Project

- Step 5. Connect Your Device

- Step 6. Configure

- Step 7. Build the Project

- Step 8. Flash onto the Device

- Step 9. Monitor

### Step 1. Set up ESP-IDF

Configure your PC according to Getting Started section of ESP-IDF Programming Guide. Windows, Linux and Mac OS operating systems are supported. Please select and follow the guide specific to ESP32 or ESP32-S2 chip. The chip name is provided in the board name.

Note

This guide uses the directory `~/esp` on Linux and macOS or `%userprofile%\esp` on Windows as an installation folder for ESP-ADF. You can use any directory, but you will need to adjust paths for the commands accordingly. Keep in mind that ESP-ADF does not support spaces in paths.

To make the installation easier and less prone to errors, use the `~/esp` default directory for the installation.

If this is your first exposure to the ESP-IDF, then it is recommended to get familiar with hello_world or blink example first.

After getting familiar with ESP-IDF, decide on which ESP-IDF version to use for your application depending on the Espressif chip that you have and your project type. For this, consult Versions section of ESP-IDF Programming Guide.

Once you successfully build, upload, and run examples for your version of ESP-IDF, you can proceed to the next step.

### Step 2. Get ESP-ADF

Now you can start installing audio-specific API / libraries provided in ESP-ADF repository.

#### Windows

Open Command Prompt and run the following commands:

    cd %userprofile%\esp
    git clone --recursive https://github.com/espressif/esp-adf.git

#### Linux and macOS

Open Terminal, and run the following commands:

    cd ~/esp
    git clone --recursive https://github.com/espressif/esp-adf.git

### Step 3. Set up the environment

Before being able to compile ESP-ADF projects, on each new session, ESP-IDF tools should be added to the PATH environment variable. To make the tools usable from the command line, some environment variables must be set. ESP-ADF provides a script which does that.

#### Windows

ESP-IDF Tools Installer for Windows creates an “ESP-IDF Command Prompt” shortcut in the Start Menu. This shortcut opens the Command Prompt and sets up all the required environment variables. You can open this shortcut and proceed to the next step.

Alternatively, if you want to use ESP-IDF in an existing Command Prompt window, you can run:

    %userprofile%\esp\esp-adf\export.bat

#### Linux and macOS

In the terminal where you have installed ESP-IDF, run:

    . $HOME/esp/esp-adf/export.sh

Note the space between the leading dot and the path!

You can also create an alias for the export script to your `.profile` or `.bash_profile` script. This way you can set up the environment in a new terminal window by typing `get_idf`:

    alias get_idf='. $HOME/esp/esp-adf/export.sh'

Note that it is not recommended to source `export.sh` from the profile script directly. Doing so activates IDF virtual environment in every terminal session (even in those where IDF is not needed), defeating the purpose of the virtual environment and likely affecting other software.

### Step 4. Start a Project

After initial preparation you are ready to build the first audio application. The process has already been described in ESP-IDF documentation. Now we would like to discuss remaining key steps and show how the toolchain is able to access the ESP-ADF components by using the `ADF_PATH` variable.

To demonstrate how to build an application, we will use get-started/play_mp3_control project from examples directory in the ADF.

#### Windows

    cd %userprofile%\esp
    xcopy /e /i %ADF_PATH%\examples\get-started\play_mp3_control play_mp3_control

#### Linux and macOS

    cd ~/esp
    cp -r $ADF_PATH/examples/get-started/play_mp3_control .

There is a range of example projects in the examples directory in ESP-ADF. You can copy any project in the same way as presented above and run it.

It is also possible to build examples in-place, without copying them first.

Important

The ESP-IDF build system does not support spaces in the paths to either ESP-IDF or to projects.

### Step 5. Connect Your Device

Connect the audio board to the PC, check under what serial port the board is visible and verify, if serial communication works as described in ESP-IDF documentation.

Note

Keep the port name handy as you will need it in the next steps.

### Step 6. Configure

Navigate to your `play_mp3_control` directory from Step 4. Start a Project and configure the project:

#### Windows

    cd %userprofile%\esp\play_mp3_control
    idf.py set-target esp32
    idf.py menuconfig

#### Linux and macOS

    cd ~/esp/play_mp3_control
    idf.py set-target esp32
    idf.py menuconfig

Note

If you are using an ESP32-S2 based board, then the second command above should be `idf.py set-target esp32s2`.

Setting the target with `idf.py set-target <target>` should be done once, after opening a new project. If the project contains some existing builds and configuration, they will be cleared and initialized. The target may be saved in environment variable to skip this step at all. See Selecting the Target in ESP-IDF Programming Guide for additional information.

If the previous steps have been done correctly, the following menu appears:

Project configuration - Home window

You are using this menu to set up your board type and other project specific variables, e.g. Wi-Fi network name and password, the processor speed, etc.

Project configuration - Board selection

Select your board from the menu, press `S` to save configuration and then `Q` to exit.

Note

The colors of the menu could be different in your terminal. You can change the appearance with the option `--style`. Please run `idf.py menuconfig --help` for further information.

### Step 7. Build the Project

Build the project by running:

    idf.py build

This command will compile the application and all ESP-IDF and ESP-ADF components, then it will generate the bootloader, partition table, and application binaries.

    $ idf.py build
     Executing action: all (aliases: build)
     Running ninja in directory /path/to/esp/play_mp3_control/build
     Executing "ninja all"...
     [0/1] Re-running CMake...

    ... (more lines of build system output)

     [1064/1064] Generating binary image from built executable
     esptool.py v3.0-dev
     Generated /path/to/esp/play_mp3_control/build/play_mp3_control.bin

     Project build complete. To flash it, run this command:
     /path/to/.espressif/python_env/idf4.2_py2.7_env/bin/python ../esp-idf/components/esptool_py/esptool/esptool.py -p (PORT) -b 460800 --before default_reset --after hard_reset --chip esp32  write_flash --flash_mode dio --flash_size detect --flash_freq 40m 0x1000 build/bootloader/bootloader.bin 0x8000 build/partition_table/partition-table.bin 0x10000 build/play_mp3_control.bin
     or run 'idf.py -p (PORT) flash'

If there are no errors, the build will finish by generating the firmware binary .bin file.

### Step 8. Flash onto the Device

Flash the binaries that you just built onto your board by running:

    idf.py -p PORT [-b BAUD] flash monitor

Replace PORT with your board’s serial port name from Step 5. Connect Your Device.

You can also change the flasher baud rate by replacing BAUD with the baud rate you need. The default baud rate is `460800`.

For more information on idf.py arguments, see Using the Build System in ESP-IDF Programming Guide.

Note

The option `flash` automatically builds and flashes the project, so running `idf.py build` is not necessary.

To upload the binaries, the board should be put into upload mode. To do so, hold down Boot button, momentarily press Reset button and release the Boot button. The upload mode may be initiated anytime during the application build, but no later than “Connecting” message is being displayed:

    ...

    esptool.py v3.0-dev
    Serial port /dev/ttyUSB0
    Connecting........_____....

Without the upload mode enabled, after showing several `....._____`, the connection will eventually time out.

Once build and upload is complete, you should see the following:

    ...

    Leaving...
    Hard resetting via RTS pin...
    Executing action: monitor
    Running idf_monitor in directory /path/to/esp/play_mp3_control
    Executing "/path/to/.espressif/python_env/idf4.2_py2.7_env/bin/python /path/to/esp/esp-idf/tools/idf_monitor.py -p /dev/ttyUSB0 -b 115200 --toolchain-prefix xtensa-esp32-elf- /path/to/esp/play_mp3_control/build/play_mp3_control.elf -m '/path/to/.espressif/python_env/idf4.2_py2.7_env/bin/python' '/path/to/esp/esp-idf/tools/idf.py'"...
    --- idf_monitor on /dev/ttyUSB0 115200 ---
    --- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---

If there are no issues by the end of the flash process, the board will reboot and start up the “play_mp3_control” application.

### Step 9. Monitor

At this point press the Reset button to start the application. Following several lines of start up log, the `play_mp3_control` application specific messages should be displayed:

    ...

    I (397) PLAY_FLASH_MP3_CONTROL: [ 1 ] Start audio codec chip
    I (427) PLAY_FLASH_MP3_CONTROL: [ 2 ] Create audio pipeline, add all elements to pipeline, and subscribe pipeline event
    I (427) PLAY_FLASH_MP3_CONTROL: [2.1] Create mp3 decoder to decode mp3 file and set custom read callback
    I (437) PLAY_FLASH_MP3_CONTROL: [2.2] Create i2s stream to write data to codec chip
    I (467) PLAY_FLASH_MP3_CONTROL: [2.3] Register all elements to audio pipeline
    I (467) PLAY_FLASH_MP3_CONTROL: [2.4] Link it together [mp3_music_read_cb]-->mp3_decoder-->i2s_stream-->[codec_chip]
    I (477) PLAY_FLASH_MP3_CONTROL: [ 3 ] Set up  event listener
    I (477) PLAY_FLASH_MP3_CONTROL: [3.1] Listening event from all elements of pipeline
    I (487) PLAY_FLASH_MP3_CONTROL: [ 4 ] Start audio_pipeline
    I (507) PLAY_FLASH_MP3_CONTROL: [ * ] Receive music info from mp3 decoder, sample_rates=44100, bits=16, ch=2
    I (7277) PLAY_FLASH_MP3_CONTROL: [ 5 ] Stop audio_pipeline

If there are no issues, besides the above log, you should hear a sound played for about 7 seconds by the speakers or headphones connected to your audio board. Reset the board to hear it again if required.

Now you are ready to try some other examples, or go right to developing your own applications. Check how the examples are made aware of location of the ESP-ADF. Open the get-started/play_mp3_control/Makefile and you should see

    include($ENV{ADF_PATH}/CMakeLists.txt)
    include($ENV{IDF_PATH}/tools/cmake/project.cmake)

The first line contains `ADF_PATH` to point the toolchain to another file in ESP-ADF directory that provides configuration variables and path to ESP-ADF components reacquired by the toolchain. You need similar `Makefile` in your own applications developed with the ESP-ADF.

### VS Code Extension

1. Follow VS Code Extension Quick Installation Guide to install ESP-IDF Visual Studio Code Extension. If the previous steps have been done correctly, the following toolbar appears:

VS Code Extension Toolbar

2. To install the ESP-ADF extension, open `Command Palette` and enter `install adf`. Then, a progress bar shows up in the lower right corner.

> If you have cloned the ESP-ADF repository before, please enter `open settings(ui)` in `Command Palette`. Go to `User > Extensions > ESP_IDF` and manually set the ESP-ADF path in `idf.espAdfPath` or `idf.espAdfPathWin` (for Windows). You can also set the ESP-ADF path in `.vscode/settings.json`.

3. In `Command Palette`, enter `show examples project`, and then a window will be opened with a list of example projects.

4. Select an example, click `Create project using example XX`, and select the directory to save the current example.

5. On the toolbar at the bottom of VS Code, click the gear symbol `menuconfig` to configure the example and click the column symbol `Build` to build the example. See available shortcut keys for VS code extensions.

6. On the toolbar at the bottom of VS Code, click the plug-in symbol `Select Port` to configure the serial port and click the lightning symbol `Flash Device` to flash firmware. After the firmware is flashed successfully, click `Monitor Device` to start the monitor function. Or, you can also use the flame symbol to build, flash, and monitor the example at the same time.

### IDF Eclipse Plugin and Espressif IDE

#### Install and Set up Environment Variables

1. Follow IDF Eclipse Plugin Quick Installation Guide to install IDF Eclipse Plugin or download and install Espressif IDE from Espressif IDE Download Link. If the previous steps have been done correctly, you can create, build and flash IDF project in the Eclipse environment.

Espressif IDE (Reskinned Eclipse)

2. To install ESP-ADF, follow section Step 2. Get ESP-ADF.

3. To set `ADF_PATH` environment variable, open `Window` > `Preferences` > `C/C++` > `Build` > `Environment` panel, click Add button and fill in `ADF_PATH`. After you complete the above steps, select `ADF_PATH` in `Environment variables` table and click Edit and OK button without changing any value (There is a bug in Eclipse CDT that is appending a null value before the path hence we need to click on edit and save it.).

> If this step does not work, you can delete `ADF_PATH` set in Eclipse and set `ADF_PATH` as system environment variable. For Windows, set environment variable in `Advanced System Setting` panel. For Linux and macOS, add `export ADF_PATH=your adf path` in file `/etc/profile`. However, it is not recommended. Doing so activates ADF virtual environment in every terminal session (including those where ADF is not needed), defeating the purpose of the virtual environment and likely affecting other software.

#### Create a New Project

1. To create new project, go to `File` > `New` > `Espressif IDF Project` and provide a project name.

2. Click Finish to create an empty project. Or click Next and check `Create a project using one of the templates` to create a project using ESP-IDF templates.

After creating a new project, you can use ESP-IDF and ESP-ADF to develop the project.

#### Import Existing Project

To import existing ESP-ADF examples, go to `File` > `Import` > `Espressif` > `Existing IDF Project` and select an ESP-ADF example (Opening an existing project directly may not be able to set the ESP target).

#### Quick Start

1. Select a project from `Project Explorer`.

2. In the Launch Mode drop-down menu, select `Run`.

3. In the Launch Configuration (auto-detected) drop-down menu, select your application.

4. Select ESP target from the third drop-down, which is called Launch Target. Click gear symbol Edit button of Launch Target to set `Serial Port`.

5. Double click `sdkconfig` file to launch the `SDK Configuration Editor`.

6. Click Build button to build the project.

7. Click Launch button to flash the project.

8. Click Open a Terminal button and select ESP-IDF Serial Monitor to view serial output.

For more information about IDF Eclipse Plugin and Espressif IDE, please refer to ESP-IDF Eclipse Plugin.

### Update ESP-ADF

After some time of using ESP-ADF, you may want to update it to take advantage of new features or bug fixes. The simplest way to do so is by deleting existing `esp-adf` folder and cloning it again, which is same as when doing initial installation described in sections Step 2. Get ESP-ADF.

Another solution is to update only what has changed. This method is useful if you have a slow connection to the GitHub. To do the update run the following commands:

    cd ~/esp/esp-adf
    git pull
    git submodule update --init --recursive

The `git pull` command is fetching and merging changes from ESP-ADF repository on GitHub. Then `git submodule update --init --recursive` is updating existing submodules or getting a fresh copy of new ones. On GitHub the submodules are represented as links to other repositories and require this additional command to get them onto your PC.

## API Reference

This API provides a way to develop audio applications using Elements like Codecs (Decoders and Encoders), Streams or Audio Processing functions.

Elements of the Audio Development Framework

The application is developed by combining the Elements into a Pipeline. A diagram below presents organization of two elements, MP3 decoder and I2S stream, in the Audio Pipeline, that has been used in get-started/play_mp3_control example.

Sample Organization of Elements in Audio Pipeline

The audio data is typically acquired using an input Stream, processed with Codecs and in some cases with Audio Processing functions, and finally output with another Stream. There is an Event Interface to facilitate communication of the application events. Interfacing with specific hardware is done using Peripherals.

See a table of contents below with links to description of all the above components.

### Audio Framework

#### Audio Element

The basic building block for the application programmer developing with ADF is the `audio_element` object. Every decoder, encoder, filter, input stream, or output stream is in fact an Audio Element.

This API has been designed and then used to implement Audio Elements provided by ADF.

The general functionality of an Element is to take some data on input, processes it, and output to the next. Each Element is run as a separate task. To enable control on particular stages of the data lifecycle from the input, during processing and up to the output, the `audio_element` object provides possibility to trigger callbacks per stage. There are seven types of available callback functions: open, seek, process, close, destroy, read and write, and they are defined in `audio_element_cfg_t`. Particular Elements typically use a subset of all available callbacks. For instance the MP3 Decoder is using open, process, close and destroy callback functions.

The available Audio Element types intended for development with this API are listed in description of audio_common.h header file under `audio_element_type_t` enumerator.

##### API Reference

###### Header File

- audio_pipeline/include/audio_element.h

###### Functions

audio_element_handle_t `audio_element_init`(audio_element_cfg_t *config)

  Initialize audio element with config.

  Return

    - audio_elemenent handle object

    - NULL

  Parameters

    - `config`: The configuration

esp_err_t `audio_element_deinit`(audio_element_handle_t el)

  Destroy audio element handle object, stop, clear, deletel all.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_setdata`(audio_element_handle_t el, void *data)

  Set context data to element handle object. It can be retrieved by calling `audio_element_getdata`.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `data`: The data pointer

void *`audio_element_getdata`(audio_element_handle_t el)

  Get context data from element handle object.

  Return

    data pointer

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_set_tag`(audio_element_handle_t el, const char *tag)

  Set elemenet tag name, or clear if tag = NULL.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] tag`: The tag name pointer

char *`audio_element_get_tag`(audio_element_handle_t el)

  Get element tag name.

  Return

    Element tag name pointer

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_setinfo`(audio_element_handle_t el, audio_element_info_t *info)

  Set audio element infomation.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `info`: The information pointer

esp_err_t `audio_element_getinfo`(audio_element_handle_t el, audio_element_info_t *info)

  Get audio element infomation.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `info`: The information pointer

esp_err_t `audio_element_set_uri`(audio_element_handle_t el, const char *uri)

  Set audio element URI.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] uri`: The uri pointer

char *`audio_element_get_uri`(audio_element_handle_t el)

  Get audio element URI.

  Return

    URI pointer

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_run`(audio_element_handle_t el)

  Start Audio Element. With this function, audio_element will start as freeRTOS task, and put the task into ‘PAUSED’ state. Note: Element does not actually start when this function returns.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_terminate`(audio_element_handle_t el)

  Terminate Audio Element. With this function, audio_element will exit the task function. Note: this API only sends request. It does not actually terminate immediately when this function returns.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_terminate_with_ticks`(audio_element_handle_t el, TickType_t ticks_to_wait)

  Terminate Audio Element with specific ticks for timeout. With this function, audio_element will exit the task function. Note: this API only sends request. It does not actually terminate immediately when this function returns.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] ticks_to_wait`: The maximum amount of time to blocking

esp_err_t `audio_element_stop`(audio_element_handle_t el)

  Request stop of the Audio Element. After receiving the stop request, the element will ignore the actions being performed (read/write, wait for the ringbuffer …) and close the task, reset the state variables. Note: this API only sends requests, Element does not actually stop when this function returns.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_wait_for_stop`(audio_element_handle_t el)

  After the `audio_element_stop` function is called, the Element task will perform some abort procedures. This function will be blocked (Time is DEFAULT_MAX_WAIT_TIME) until Element Task has done and exit.

  Return

    - ESP_OK, Success

    - ESP_FAIL, The state is not AEL_STATE_RUNNING

    - ESP_ERR_TIMEOUT, Timeout

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_wait_for_stop_ms`(audio_element_handle_t el, TickType_t ticks_to_wait)

  After the `audio_element_stop` function is called, the Element task will perform some abort procedures. The maximum amount of time should block waiting for Element task has stopped.

  Return

    - ESP_OK, Success

    - ESP_FAIL, The state is not AEL_STATE_RUNNING

    - ESP_ERR_TIMEOUT, Timeout

  Parameters

    - `[in] el`: The audio element handle

    - `[in] ticks_to_wait`: The maximum amount of time to wait for stop

esp_err_t `audio_element_pause`(audio_element_handle_t el)

  Request audio Element enter ‘PAUSE’ state. In this state, the task will wait for any event.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_resume`(audio_element_handle_t el, float wait_for_rb_threshold, TickType_t timeout)

  Request audio Element enter ‘RUNNING’ state. In this state, the task listens to events and invokes the callback functions. At the same time it will wait until the size/total_size of the output ringbuffer is greater than or equal to `wait_for_rb_threshold`. If the timeout period has been exceeded and ringbuffer output has not yet reached `wait_for_rb_threshold` then the function will return.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] wait_for_rb_threshold`: The wait for rb threshold (0 .. 1)

    - `[in] timeout`: The timeout

esp_err_t `audio_element_msg_set_listener`(audio_element_handle_t el, audio_event_iface_handle_t listener)

  This function will add a `listener` to listen to all events from audio element `el`. Any event from el->external_event will be send to the `listener`.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `el`: The audio element handle

    - `listener`: The event will be listen to

esp_err_t `audio_element_set_event_callback`(audio_element_handle_t el, event_cb_func cb_func, void *ctx)

  This function will add a `callback` to be called from audio element `el`. Any event to caller will cause to call callback function.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `el`: The audio element handle

    - `cb_func`: The callback function

    - `ctx`: Caller context

esp_err_t `audio_element_msg_remove_listener`(audio_element_handle_t el, audio_event_iface_handle_t listener)

  Remove listener out of el. No new events will be sent to the listener.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `listener`: The listener

esp_err_t `audio_element_set_input_ringbuf`(audio_element_handle_t el, ringbuf_handle_t rb)

  Set Element input ringbuffer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] rb`: The ringbuffer handle

ringbuf_handle_t `audio_element_get_input_ringbuf`(audio_element_handle_t el)

  Get Element input ringbuffer.

  Return

    ringbuf_handle_t

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_set_output_ringbuf`(audio_element_handle_t el, ringbuf_handle_t rb)

  Set Element output ringbuffer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] rb`: The ringbuffer handle

ringbuf_handle_t `audio_element_get_output_ringbuf`(audio_element_handle_t el)

  Get Element output ringbuffer.

  Return

    ringbuf_handle_t

  Parameters

    - `[in] el`: The audio element handle

audio_element_state_t `audio_element_get_state`(audio_element_handle_t el)

  Get current Element state.

  Return

    audio_element_state_t

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_abort_input_ringbuf`(audio_element_handle_t el)

  If the element is requesting data from the input ringbuffer, this function forces it to abort.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_abort_output_ringbuf`(audio_element_handle_t el)

  If the element is waiting to write data to the ringbuffer output, this function forces it to abort.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_wait_for_buffer`(audio_element_handle_t el, int size_expect, TickType_t timeout)

  This function will wait until the sizeof the output ringbuffer is greater than or equal to `size_expect`. If the timeout period has been exceeded and ringbuffer output has not yet reached `size_expect` then the function will return `ESP_FAIL`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] size_expect`: The size expect

    - `[in] timeout`: The timeout

esp_err_t `audio_element_report_status`(audio_element_handle_t el, audio_element_status_t status)

  Element will sendout event (status) to event by this function.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] status`: The status

esp_err_t `audio_element_report_info`(audio_element_handle_t el)

  Element will sendout event (information) to event by this function.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_report_codec_fmt`(audio_element_handle_t el)

  Element will sendout event (codec format) to event by this function.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_report_pos`(audio_element_handle_t el)

  Element will sendout event with a duplicate information by this function.

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_NO_MEM

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_set_input_timeout`(audio_element_handle_t el, TickType_t timeout)

  Set input read timeout (default is `portMAX_DELAY`).

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] timeout`: The timeout

esp_err_t `audio_element_set_output_timeout`(audio_element_handle_t el, TickType_t timeout)

  Set output read timeout (default is `portMAX_DELAY`).

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] timeout`: The timeout

esp_err_t `audio_element_reset_input_ringbuf`(audio_element_handle_t el)

  Reset inputbuffer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_finish_state`(audio_element_handle_t el)

  Set element finish state.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_change_cmd`(audio_element_handle_t el, audio_element_msg_cmd_t cmd)

  Change element running state with specific command.

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG Element handle is null

  Parameters

    - `[in] el`: The audio element handle

    - `[in] cmd`: Specific command from audio_element_msg_cmd_t

esp_err_t `audio_element_reset_output_ringbuf`(audio_element_handle_t el)

  Reset outputbuffer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

audio_element_err_t `audio_element_input`(audio_element_handle_t el, char *buffer, int wanted_size)

  Call this function to provide Element input data. Depending on setup using ringbuffer or function callback, Element invokes read ringbuffer, or calls read callback funtion.

  Return

    - > 0 number of bytes produced

    - <=0 audio_element_err_t

  Parameters

    - `[in] el`: The audio element handle

    - `buffer`: The buffer pointer

    - `[in] wanted_size`: The wanted size

audio_element_err_t `audio_element_output`(audio_element_handle_t el, char *buffer, int write_size)

  Call this function to sendout Element output data. Depending on setup using ringbuffer or function callback, Element will invoke write to ringbuffer, or call write callback funtion.

  Return

    - > 0 number of bytes written

    - <=0 audio_element_err_t

  Parameters

    - `[in] el`: The audio element handle

    - `buffer`: The buffer pointer

    - `[in] write_size`: The write size

esp_err_t `audio_element_set_read_cb`(audio_element_handle_t el, stream_func fn, void *context)

  This API allows the application to set a read callback for the first audio_element in the pipeline for allowing the pipeline to interface with other systems. The callback is invoked every time the audio element requires data to be processed.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] fn`: Callback read function. The callback function should return number of bytes read or -1 in case of error in reading. Note that the callback function may decide to block and that may block the entire pipeline.

    - `[in] context`: An optional context which will be passed to callback function on every invocation

esp_err_t `audio_element_set_write_cb`(audio_element_handle_t el, stream_func fn, void *context)

  This API allows the application to set a write callback for the last audio_element in the pipeline for allowing the pipeline to interface with other systems. The callback is invoked every time the audio element has a processed data that needs to be passed forward.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element

    - `[in] fn`: Callback write function The callback function should return number of bytes written or -1 in case of error in writing. Note that the callback function may decide to block and that may block the entire pipeline.

    - `[in] context`: An optional context which will be passed to callback function on every invocation

stream_func `audio_element_get_write_cb`(audio_element_handle_t el)

  Get callback write function that register to the element.

  Return

    - Callback write function pointer

    - NULL Failed

  Parameters

    - `[in] el`: The audio element

stream_func `audio_element_get_read_cb`(audio_element_handle_t el)

  Get callback read function that register to the element.

  Return

    - Callback read function pointer

    - NULL Failed

  Parameters

    - `[in] el`: The audio element

QueueHandle_t `audio_element_get_event_queue`(audio_element_handle_t el)

  Get External queue of Emitter. We can read any event that has been send out of Element from this `QueueHandle_t`.

  Return

    QueueHandle_t

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_set_ringbuf_done`(audio_element_handle_t el)

  Set inputbuffer and outputbuffer have finished.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_reset_state`(audio_element_handle_t el)

  Enforce ‘AEL_STATE_INIT’ state.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

int `audio_element_get_output_ringbuf_size`(audio_element_handle_t el)

  Get Element output ringbuffer size.

  Return

    - =0: Parameter NULL

    - >0: Size of ringbuffer

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_set_output_ringbuf_size`(audio_element_handle_t el, int rb_size)

  Set Element output ringbuffer size.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] rb_size`: Size of the ringbuffer

int `audio_element_multi_input`(audio_element_handle_t el, char *buffer, int wanted_size, int index, TickType_t ticks_to_wait)

  Call this function to read data from multi input ringbuffer by given index.

  Return

    - ESP_ERR_INVALID_SIZE

    - Others are same as the `rb_read`

  Parameters

    - `el`: The audio element handle

    - `buffer`: The buffer pointer

    - `wanted_size`: The wanted size

    - `index`: The index of multi input ringbuffer, start from `0`, should be less than `NUMBER_OF_MULTI_RINGBUF`

    - `ticks_to_wait`: Timeout of ringbuffer

int `audio_element_multi_output`(audio_element_handle_t el, char *buffer, int wanted_size, TickType_t ticks_to_wait)

  Call this function write data by multi output ringbuffer.

  Return

    - The return value is same as the `rb_write`

  Parameters

    - `[in] el`: The audio element handle

    - `buffer`: The buffer pointer

    - `[in] wanted_size`: The wanted size

    - `ticks_to_wait`: Timeout of ringbuffer

esp_err_t `audio_element_set_multi_input_ringbuf`(audio_element_handle_t el, ringbuf_handle_t rb, int index)

  Set multi input ringbuffer Element.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] rb`: The ringbuffer handle

    - `[in] index`: Index of multi ringbuffer, starts from `0`, should be less than `NUMBER_OF_MULTI_RINGBUF`

esp_err_t `audio_element_set_multi_output_ringbuf`(audio_element_handle_t el, ringbuf_handle_t rb, int index)

  Set multi output ringbuffer Element.

  Return

    - ESP_OK

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] el`: The audio element handle

    - `[in] rb`: The ringbuffer handle

    - `[in] index`: Index of multi ringbuffer, starts from `0`, should be less than `NUMBER_OF_MULTI_RINGBUF`

ringbuf_handle_t `audio_element_get_multi_input_ringbuf`(audio_element_handle_t el, int index)

  Get handle of multi input ringbuffer Element by index.

  Return

    - NULL Error

    - Others ringbuf_handle_t

  Parameters

    - `[in] el`: The audio element handle

    - `[in] index`: Index of multi ringbuffer, starts from `0`, should be less than `NUMBER_OF_MULTI_RINGBUF`

ringbuf_handle_t `audio_element_get_multi_output_ringbuf`(audio_element_handle_t el, int index)

  Get handle of multi output ringbuffer Element by index.

  Return

    - NULL Error

    - Others ringbuf_handle_t

  Parameters

    - `[in] el`: The audio element handle

    - `[in] index`: Index of multi ringbuffer, starts from `0`, should be less than `NUMBER_OF_MULTI_RINGBUF`

esp_err_t `audio_element_process_init`(audio_element_handle_t el)

  Provides a way to call element’s `open`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_process_deinit`(audio_element_handle_t el)

  Provides a way to call element’s `close`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_seek`(audio_element_handle_t el, void *in_data, int in_size, void *out_data, int *out_size)

  Call element’s `seek`

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_NOT_SUPPORTED

  Parameters

    - `[in] el`: The audio element handle

    - `[in] in_data`: A pointer to in data

    - `[in] in_size`: The size of the `in_data`

    - `[out] out_data`: A pointer to the out data

    - `[out] out_size`: The size of the `out_data`

bool `audio_element_is_stopping`(audio_element_handle_t el)

  Get Element stopping flag.

  Return

    element’s stopping flag

  Parameters

    - `[in] el`: The audio element handle

esp_err_t `audio_element_update_byte_pos`(audio_element_handle_t el, int pos)

  Update the byte position of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] pos`: The byte_pos accumulated by this value

esp_err_t `audio_element_set_byte_pos`(audio_element_handle_t el, int pos)

  Set the byte position of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] pos`: This value is assigned to byte_pos

esp_err_t `audio_element_update_total_bytes`(audio_element_handle_t el, int total_bytes)

  Update the total bytes of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] total_bytes`: The total_bytes accumulated by this value

esp_err_t `audio_element_set_total_bytes`(audio_element_handle_t el, int total_bytes)

  Set the total bytes of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] total_bytes`: This value is assigned to total_bytes

esp_err_t `audio_element_set_bps`(audio_element_handle_t el, int bit_rate)

  Set the bps of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] bit_rate`: This value is assigned to bps

esp_err_t `audio_element_set_codec_fmt`(audio_element_handle_t el, int format)

  Set the codec format of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] format`: This value is assigned to codec_fmt

esp_err_t `audio_element_set_music_info`(audio_element_handle_t el, int sample_rates, int channels, int bits)

  Set the sample_rate, channels, bits of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] sample_rates`: Sample_rates of music information

    - `[in] channels`: Channels of music information

    - `[in] bits`: Bits of music information

esp_err_t `audio_element_set_duration`(audio_element_handle_t el, int duration)

  Set the duration of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] duration`: This value is assigned to duration

esp_err_t `audio_element_set_reserve_user0`(audio_element_handle_t el, int user_data0)

  Set the user_data_0 of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] user_data0`: This value is assigned to user_data_0

esp_err_t `audio_element_set_reserve_user1`(audio_element_handle_t el, int user_data1)

  Set the user_data_1 of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] user_data1`: This value is assigned to user_data_1

esp_err_t `audio_element_set_reserve_user2`(audio_element_handle_t el, int user_data2)

  Set the user_data_2 of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] user_data2`: This value is assigned to user_data_2

esp_err_t `audio_element_set_reserve_user3`(audio_element_handle_t el, int user_data3)

  Set the user_data_3 of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] user_data3`: This value is assigned to user_data_3

esp_err_t `audio_element_set_reserve_user4`(audio_element_handle_t el, int user_data4)

  Set the user_data_4 of element information.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] user_data4`: This value is assigned to user_data_4

###### Structures

struct `audio_element_reserve_data_t`

  Audio Element user reserved data.

  Public Members

  int `user_data_0`

    user data 0

  int `user_data_1`

    user data 1

  int `user_data_2`

    user data 2

  int `user_data_3`

    user data 3

  int `user_data_4`

    user data 4

struct `audio_element_info_t`

  Audio Element informations.

  Public Members

  int `sample_rates`

    Sample rates in Hz

  int `channels`

    Number of audio channel, mono is 1, stereo is 2

  int `bits`

    Bit wide (8, 16, 24, 32 bits)

  int `bps`

    Bit per second

  int64_t `byte_pos`

    The current position (in bytes) being processed for an element

  int64_t `total_bytes`

    The total bytes for an element

  int `duration`

    The duration for an element (optional)

  char *`uri`

    URI (optional)

  esp_codec_type_t `codec_fmt`

    Music format (optional)

  audio_element_reserve_data_t `reserve_data`

    This value is reserved for user use (optional)

struct `audio_element_cfg_t`

  Audio Element configurations. Each Element at startup will be a self-running task. These tasks will execute the callback open -> [loop: read -> process -> write] -> close. These callback functions are provided by the user corresponding to this configuration.

  Public Members

  el_io_func `open`

    Open callback function

  ctrl_func `seek`

    Seek callback function

  process_func `process`

    Process callback function

  el_io_func `close`

    Close callback function

  el_io_func `destroy`

    Destroy callback function

  stream_func `read`

    Read callback function

  stream_func `write`

    Write callback function

  int `buffer_len`

    Buffer length use for an Element

  int `task_stack`

    Element task stack

  int `task_prio`

    Element task priority (based on freeRTOS priority)

  int `task_core`

    Element task running in core (0 or 1)

  int `out_rb_size`

    Output ringbuffer size

  void *`data`

    User context

  const char *`tag`

    Element tag

  bool `stack_in_ext`

    Try to allocate stack in external memory

  int `multi_in_rb_num`

    The number of multiple input ringbuffer

  int `multi_out_rb_num`

    The number of multiple output ringbuffer

###### Macros

`AUDIO_ELEMENT_INFO_DEFAULT`()

`DEFAULT_ELEMENT_RINGBUF_SIZE`

`DEFAULT_ELEMENT_BUFFER_LENGTH`

`DEFAULT_ELEMENT_STACK_SIZE`

`DEFAULT_ELEMENT_TASK_PRIO`

`DEFAULT_ELEMENT_TASK_CORE`

`DEFAULT_AUDIO_ELEMENT_CONFIG`()

###### Type Definitions

typedef struct audio_element *`audio_element_handle_t`

typedef esp_err_t (*`el_io_func`)(audio_element_handle_t self)

typedef audio_element_err_t (*`process_func`)(audio_element_handle_t self, char *el_buffer, int el_buf_len)

typedef audio_element_err_t (*`stream_func`)(audio_element_handle_t self, char *buffer, int len, TickType_t ticks_to_wait, void *context)

typedef esp_err_t (*`event_cb_func`)(audio_element_handle_t el, audio_event_iface_msg_t *event, void *ctx)

typedef esp_err_t (*`ctrl_func`)(audio_element_handle_t self, void *in_data, int in_size, void *out_data, int *out_size)

###### Enumerations

enum `audio_element_err_t`

  Values:

  `AEL_IO_OK` = ESP_OK
  `AEL_IO_FAIL` = ESP_FAIL
  `AEL_IO_DONE` = -2
  `AEL_IO_ABORT` = -3
  `AEL_IO_TIMEOUT` = -4
  `AEL_PROCESS_FAIL` = -5

enum `audio_element_state_t`

  Audio element state.

  Values:

  `AEL_STATE_NONE` = 0
  `AEL_STATE_INIT` = 1
  `AEL_STATE_INITIALIZING` = 2
  `AEL_STATE_RUNNING` = 3
  `AEL_STATE_PAUSED` = 4
  `AEL_STATE_STOPPED` = 5
  `AEL_STATE_FINISHED` = 6
  `AEL_STATE_ERROR` = 7

enum `audio_element_msg_cmd_t`

  Audio element action command, process on dispatcher

  Values:

  `AEL_MSG_CMD_NONE` = 0
  `AEL_MSG_CMD_FINISH` = 2
  `AEL_MSG_CMD_STOP` = 3
  `AEL_MSG_CMD_PAUSE` = 4
  `AEL_MSG_CMD_RESUME` = 5
  `AEL_MSG_CMD_DESTROY` = 6
  `AEL_MSG_CMD_REPORT_STATUS` = 8
  `AEL_MSG_CMD_REPORT_MUSIC_INFO` = 9
  `AEL_MSG_CMD_REPORT_CODEC_FMT` = 10
  `AEL_MSG_CMD_REPORT_POSITION` = 11

enum `audio_element_status_t`

  Audio element status report

  Values:

  `AEL_STATUS_NONE` = 0
  `AEL_STATUS_ERROR_OPEN` = 1
  `AEL_STATUS_ERROR_INPUT` = 2
  `AEL_STATUS_ERROR_PROCESS` = 3
  `AEL_STATUS_ERROR_OUTPUT` = 4
  `AEL_STATUS_ERROR_CLOSE` = 5
  `AEL_STATUS_ERROR_TIMEOUT` = 6
  `AEL_STATUS_ERROR_UNKNOWN` = 7
  `AEL_STATUS_INPUT_DONE` = 8
  `AEL_STATUS_INPUT_BUFFERING` = 9
  `AEL_STATUS_OUTPUT_DONE` = 10
  `AEL_STATUS_OUTPUT_BUFFERING` = 11
  `AEL_STATUS_STATE_RUNNING` = 12
  `AEL_STATUS_STATE_PAUSED` = 13
  `AEL_STATUS_STATE_STOPPED` = 14
  `AEL_STATUS_STATE_FINISHED` = 15
  `AEL_STATUS_MOUNTED` = 16
  `AEL_STATUS_UNMOUNTED` = 17

#### Audio Pipeline

Dynamic combination of a group of linked Elements is done using the Audio Pipeline. You do not deal with the individual elements but with just one audio pipeline. Every element is connected by a ringbuffer. The Audio Pipeline also takes care of forwarding messages from the element tasks to an application.

A diagram below presents organization of three elements, HTTP reader stream, MP3 decoder and I2S writer stream, in the Audio Pipeline, that has been used in player/pipeline_http_mp3 example.

Sample Organization of Elements in Audio Pipeline

##### API Reference

###### Header File

- audio_pipeline/include/audio_pipeline.h

###### Functions

audio_pipeline_handle_t `audio_pipeline_init`(audio_pipeline_cfg_t *config)

  Initialize audio_pipeline_handle_t object audio_pipeline is responsible for controlling the audio data stream and connecting the audio elements with the ringbuffer It will connect and start the audio element in order, responsible for retrieving the data from the previous element and passing it to the element after it. Also get events from each element, process events or pass it to a higher layer.

  Return

    - audio_pipeline_handle_t on success

    - NULL when any errors

  Parameters

    - `config`: The configuration - audio_pipeline_cfg_t

esp_err_t `audio_pipeline_deinit`(audio_pipeline_handle_t pipeline)

  This function removes all of the element’s links in audio_pipeline, cancels the registration of all events, invokes the destroy functions of the registered elements, and frees the memory allocated by the init function. Briefly, frees all memory.

  Return

    ESP_OK

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_register`(audio_pipeline_handle_t pipeline, audio_element_handle_t el, const char *name)

  Registering an element for audio_pipeline, each element can be registered multiple times, but `name` (as String) must be unique in audio_pipeline, which is used to identify the element for link creation mentioned in the `audio_pipeline_link`

  Note

    Because of stop pipeline or pause pipeline depend much on register order. Please register element strictly in the following order: input element first, process middle, output element last.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] el`: The Audio Element Handle

    - `[in] name`: The name identifier of the audio_element in this audio_pipeline

esp_err_t `audio_pipeline_unregister`(audio_pipeline_handle_t pipeline, audio_element_handle_t el)

  Unregister the audio_element in audio_pipeline, remove it from the list.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] el`: The Audio Element Handle

esp_err_t `audio_pipeline_run`(audio_pipeline_handle_t pipeline)

  Start Audio Pipeline.

            With this function audio_pipeline will create tasks for all elements,
            that have been linked using the linking functions.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_terminate`(audio_pipeline_handle_t pipeline)

  Stop Audio Pipeline.

            With this function audio_pipeline will destroy tasks of all elements,
            that have been linked using the linking functions.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_terminate_with_ticks`(audio_pipeline_handle_t pipeline, TickType_t ticks_to_wait)

  Stop Audio Pipeline with specific ticks for timeout.

            With this function audio_pipeline will destroy tasks of all elements,
            that have been linked using the linking functions.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] ticks_to_wait`: The maximum amount of time to block wait for element destroy

esp_err_t `audio_pipeline_resume`(audio_pipeline_handle_t pipeline)

  This function will set all the elements to the `RUNNING` state and process the audio data as an inherent feature of audio_pipeline.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_pause`(audio_pipeline_handle_t pipeline)

  This function will set all the elements to the `PAUSED` state. Everything remains the same except the data processing is stopped.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_stop`(audio_pipeline_handle_t pipeline)

  Stop all of the linked elements. Used with `audio_pipeline_wait_for_stop` to keep in sync. The link state of the elements in the pipeline is kept, events are still registered. The stopped audio_pipeline restart by `audio_pipeline_resume`.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_wait_for_stop`(audio_pipeline_handle_t pipeline)

  The `audio_pipeline_stop` function sends requests to the elements and exits. But they need time to get rid of time-blocking tasks. This function will wait `portMAX_DELAY` until all the Elements in the pipeline actually stop.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_wait_for_stop_with_ticks`(audio_pipeline_handle_t pipeline, TickType_t ticks_to_wait)

  The `audio_pipeline_stop` function sends requests to the elements and exits. But they need time to get rid of time-blocking tasks. This function will wait `ticks_to_wait` until all the Elements in the pipeline actually stop.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] ticks_to_wait`: The maximum amount of time to block wait for stop

esp_err_t `audio_pipeline_link`(audio_pipeline_handle_t pipeline, const char *link_tag[], int link_num)

  The audio_element added to audio_pipeline will be unconnected before it is called by this function. Based on element’s `name` already registered by `audio_pipeline_register`, the path of the data will be linked in the order of the link_tag. Element at index 0 is first, and index `link_num -1` is final. As well as audio_pipeline will subscribe all element’s events.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `link_tag`: Array of element `name` was registered by `audio_pipeline_register`

    - `[in] link_num`: Total number of elements of the `link_tag` array

esp_err_t `audio_pipeline_unlink`(audio_pipeline_handle_t pipeline)

  Removes the connection of the elements, as well as unsubscribe events.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

audio_element_handle_t `audio_pipeline_get_el_by_tag`(audio_pipeline_handle_t pipeline, const char *tag)

  Find un-kept element from registered pipeline by tag.

  Return

    - NULL when any errors

    - Others on success

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] tag`: A char pointer

audio_element_handle_t `audio_pipeline_get_el_once`(audio_pipeline_handle_t pipeline, const audio_element_handle_t start_el, const char *tag)

  Based on beginning element to find un-kept element from registered pipeline by tag.

  Return

    - NULL when any errors

    - Others on success

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] start_el`: Specific beginning element

    - `[in] tag`: A char pointer

esp_err_t `audio_pipeline_remove_listener`(audio_pipeline_handle_t pipeline)

  Remove event listener from this audio_pipeline.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_set_listener`(audio_pipeline_handle_t pipeline, audio_event_iface_handle_t evt)

  Set event listner for this audio_pipeline, any event from this pipeline can be listen to by `evt`

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] evt`: The Event Handle

audio_event_iface_handle_t `audio_pipeline_get_event_iface`(audio_pipeline_handle_t pipeline)

  Get the event iface using by this pipeline.

  Return

    The Event Handle

  Parameters

    - `[in] pipeline`: The pipeline

esp_err_t `audio_pipeline_link_insert`(audio_pipeline_handle_t pipeline, bool first, audio_element_handle_t prev, ringbuf_handle_t conect_rb, audio_element_handle_t next)

  Insert the specific audio_element to audio_pipeline, previous element connect to the next element by ring buffer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] pipeline`: The audio pipeline handle

    - `[in] first`: Previous element is first input element, need to set `true`

    - `[in] prev`: Previous element

    - `[in] conect_rb`: Connect ring buffer

    - `[in] next`: Next element

esp_err_t `audio_pipeline_register_more`(audio_pipeline_handle_t pipeline, audio_element_handle_t element_1, ...)

  Register a NULL-terminated list of elements to audio_pipeline.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] pipeline`: The audio pipeline handle

    - `[in] element_1`: The element to add to the audio_pipeline.

    - `[in] ...`: Additional elements to add to the audio_pipeline.

esp_err_t `audio_pipeline_unregister_more`(audio_pipeline_handle_t pipeline, audio_element_handle_t element_1, ...)

  Unregister a NULL-terminated list of elements to audio_pipeline.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] pipeline`: The audio pipeline handle

    - `[in] element_1`: The element to add to the audio_pipeline.

    - `[in] ...`: Additional elements to add to the audio_pipeline.

esp_err_t `audio_pipeline_link_more`(audio_pipeline_handle_t pipeline, audio_element_handle_t element_1, ...)

  Adds a NULL-terminated list of elements to audio_pipeline.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] pipeline`: The audio pipeline handle

    - `[in] element_1`: The element to add to the audio_pipeline.

    - `[in] ...`: Additional elements to add to the audio_pipeline.

esp_err_t `audio_pipeline_listen_more`(audio_pipeline_handle_t pipeline, audio_element_handle_t element_1, ...)

  Subscribe a NULL-terminated list of element’s events to audio_pipeline.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] pipeline`: The audio pipeline handle

    - `[in] element_1`: The element event to subscribe to the audio_pipeline.

    - `[in] ...`: Additional elements event to subscribe to the audio_pipeline.

esp_err_t `audio_pipeline_check_items_state`(audio_pipeline_handle_t pipeline, audio_element_handle_t dest_el, audio_element_status_t status)

  Update the destination element state and check the all of linked elements state are same.

  Return

    - ESP_OK All linked elements state are same.

    - ESP_FAIL All linked elements state are not same.

  Parameters

    - `[in] pipeline`: The audio pipeline handle

    - `[in] dest_el`: Destination element

    - `[in] status`: The new status

esp_err_t `audio_pipeline_reset_items_state`(audio_pipeline_handle_t pipeline)

  Reset pipeline element items state to `AEL_STATUS_NONE`

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_reset_ringbuffer`(audio_pipeline_handle_t pipeline)

  Reset pipeline element ringbuffer.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_reset_elements`(audio_pipeline_handle_t pipeline)

  Reset Pipeline linked elements state.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

esp_err_t `audio_pipeline_reset_kept_state`(audio_pipeline_handle_t pipeline, audio_element_handle_t el)

  Reset the specific element kept state.

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] el`: The Audio element Handle

esp_err_t `audio_pipeline_breakup_elements`(audio_pipeline_handle_t pipeline, audio_element_handle_t kept_ctx_el)

  Break up all the linked elements of specific `pipeline`. The include and before `kept_ctx_el` working (AEL_STATE_RUNNING or AEL_STATE_PAUSED) elements and connected ringbuffer will be reserved.

  Note

    There is no element reserved when `kept_ctx_el` is NULL. This function will unsubscribe all element’s events.

  Return

    - ESP_OK All linked elements state are same.

    - ESP_ERR_INVALID_ARG Invalid parameters.

  Parameters

    - `[in] pipeline`: The audio pipeline handle

    - `[in] kept_ctx_el`: Destination keep elements

esp_err_t `audio_pipeline_relink`(audio_pipeline_handle_t pipeline, const char *link_tag[], int link_num)

  Basing on element’s `name` already registered by `audio_pipeline_register`, relink the pipeline following the order of `names` in the `link_tag.

  Note

    If the ringbuffer is not enough to connect the new pipeline will create new ringbuffer.

  Return

    - ESP_OK All linked elements state are same.

    - ESP_FAIL Error.

    - ESP_ERR_INVALID_ARG Invalid parameters.

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `link_tag`: Array of elements `name` that was registered by `audio_pipeline_register`

    - `[in] link_num`: Total number of elements of the `link_tag` array

esp_err_t `audio_pipeline_relink_more`(audio_pipeline_handle_t pipeline, audio_element_handle_t element_1, ...)

  Adds a NULL-terminated list of elements to audio_pipeline.

  Note

    If the ringbuffer is not enough to connect the new pipeline will create new ringbuffer.

  Return

    - ESP_OK All linked elements state are same.

    - ESP_FAIL Error.

    - ESP_ERR_INVALID_ARG Invalid parameters.

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] element_1`: The element to add to the audio_pipeline.

    - `[in] ...`: Additional elements to add to the audio_pipeline.

esp_err_t `audio_pipeline_change_state`(audio_pipeline_handle_t pipeline, audio_element_state_t new_state)

  Set the pipeline state.

  Return

    - ESP_OK All linked elements state are same.

    - ESP_FAIL Error.

  Parameters

    - `[in] pipeline`: The Audio Pipeline Handle

    - `[in] new_state`: The new state will be set

###### Structures

struct `audio_pipeline_cfg`

  Audio Pipeline configurations.

  Public Members

  int `rb_size`

    Audio Pipeline ringbuffer size

###### Macros

`DEFAULT_PIPELINE_RINGBUF_SIZE`

`DEFAULT_AUDIO_PIPELINE_CONFIG`()

###### Type Definitions

typedef struct audio_pipeline *`audio_pipeline_handle_t`

typedef struct audio_pipeline_cfg `audio_pipeline_cfg_t`

  Audio Pipeline configurations.

#### Event Interface

The ADF provides the Event Interface API to establish communication between Audio Elements in a pipeline. The API is built around FreeRTOS queue. It implements ‘listeners’ to watch for incoming messages and inform about them with a callback function.

##### Application Examples

Implementation of this API is demonstrated in couple of examples including get-started/play_mp3_control.

##### API Reference

###### Header File

- audio_pipeline/include/audio_event_iface.h

###### Functions

audio_event_iface_handle_t `audio_event_iface_init`(audio_event_iface_cfg_t *config)

  Initialize audio event.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `config`: The configurations

esp_err_t `audio_event_iface_destroy`(audio_event_iface_handle_t evt)

  Cleanup event, it doesn’t free evt pointer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `evt`: The event

esp_err_t `audio_event_iface_set_listener`(audio_event_iface_handle_t evt, audio_event_iface_handle_t listener)

  Add audio event `evt` to the listener, then we can listen `evt` event from `listen`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `listener`: The event can listen another event

    - `evt`: The event to be added to

esp_err_t `audio_event_iface_remove_listener`(audio_event_iface_handle_t listener, audio_event_iface_handle_t evt)

  Remove audio event `evt` from the listener.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `listener`: The event listener

    - `evt`: The event to be removed from

esp_err_t `audio_event_iface_set_cmd_waiting_timeout`(audio_event_iface_handle_t evt, TickType_t wait_time)

  Set current queue wait time for the event.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `evt`: The event

    - `[in] wait_time`: The wait time

esp_err_t `audio_event_iface_waiting_cmd_msg`(audio_event_iface_handle_t evt)

  Waiting internal queue message.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `evt`: The event

esp_err_t `audio_event_iface_cmd`(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg)

  Trigger an event for internal queue with a message.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `evt`: The event

    - `msg`: The message

esp_err_t `audio_event_iface_cmd_from_isr`(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg)

  It’s same with `audio_event_iface_cmd`, but can send a message from ISR.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] evt`: The event

    - `msg`: The message

esp_err_t `audio_event_iface_sendout`(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg)

  Trigger and event out with a message.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `evt`: The event

    - `msg`: The message

esp_err_t `audio_event_iface_discard`(audio_event_iface_handle_t evt)

  Discard all ongoing event message.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `evt`: The event

esp_err_t `audio_event_iface_listen`(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg, TickType_t wait_time)

  Listening and invoke callback function if there are any event are comming.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `evt`: The event

    - `msg`: The message

    - `wait_time`: The wait time

QueueHandle_t `audio_event_iface_get_queue_handle`(audio_event_iface_handle_t evt)

  Get External queue handle of Emmitter.

  Return

    External QueueHandle_t

  Parameters

    - `[in] evt`: The external queue

esp_err_t `audio_event_iface_read`(audio_event_iface_handle_t evt, audio_event_iface_msg_t *msg, TickType_t wait_time)

  Read the event from all the registered event emitters in the queue set of the interface.

  Return

    - ESP_OK On successful receiving of event

    - ESP_FAIL In case of a timeout or invalid parameter passed

  Parameters

    - `[in] evt`: The event interface

    - `[out] msg`: The pointer to structure in which event is to be received

    - `[in] wait_time`: Timeout for receiving event

QueueHandle_t `audio_event_iface_get_msg_queue_handle`(audio_event_iface_handle_t evt)

  Get Internal queue handle of Emmitter.

  Return

    Internal QueueHandle_t

  Parameters

    - `[in] evt`: The Internal queue

esp_err_t `audio_event_iface_set_msg_listener`(audio_event_iface_handle_t evt, audio_event_iface_handle_t listener)

  Add audio internal event `evt` to the listener, then we can listen `evt` event from `listen`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `listener`: The event can listen another event

    - `evt`: The event to be added to

###### Structures

struct `audio_event_iface_msg_t`

  Event message

  Public Members

  int `cmd`

    Command id

  void *`data`

    Data pointer

  int `data_len`

    Data length

  void *`source`

    Source event

  int `source_type`

    Source type (To know where it came from)

  bool `need_free_data`

    Need to free data pointer after the event has been processed

struct `audio_event_iface_cfg_t`

  Event interface configurations

  Public Members

  int `internal_queue_size`

    It’s optional, Queue size for event `internal_queue`

  int `external_queue_size`

    It’s optional, Queue size for event `external_queue`

  int `queue_set_size`

    It’s optional, QueueSet size for event `queue_set`

  on_event_iface_func `on_cmd`

    Function callback for listener when any event arrived

  void *`context`

    Context will pass to callback function

  TickType_t `wait_time`

    Timeout to check for event queue

  int `type`

    it will pass to audio_event_iface_msg_t source_type (To know where it came from)

###### Macros

`DEFAULT_AUDIO_EVENT_IFACE_SIZE`

`AUDIO_EVENT_IFACE_DEFAULT_CFG`()

###### Type Definitions

typedef esp_err_t (*`on_event_iface_func`)(audio_event_iface_msg_t *, void *)

typedef struct audio_event_iface *`audio_event_iface_handle_t`

#### Audio Common

Enumerations that define type of Audio Elements, type and format of Codecs and type of Streams.

##### API Reference

###### Header File

- audio_pipeline/include/audio_common.h

###### Macros

`ELEMENT_SUB_TYPE_OFFSET`

`mem_assert`(x)

###### Enumerations

enum `audio_element_type_t`

  Values:

  `AUDIO_ELEMENT_TYPE_UNKNOW` = 0x01 << ELEMENT_SUB_TYPE_OFFSET
  `AUDIO_ELEMENT_TYPE_ELEMENT` = 0x01 << (ELEMENT_SUB_TYPE_OFFSET + 1)
  `AUDIO_ELEMENT_TYPE_PLAYER` = 0x01 << (ELEMENT_SUB_TYPE_OFFSET + 2)
  `AUDIO_ELEMENT_TYPE_SERVICE` = 0x01 << (ELEMENT_SUB_TYPE_OFFSET + 3)
  `AUDIO_ELEMENT_TYPE_PERIPH` = 0x01 << (ELEMENT_SUB_TYPE_OFFSET + 4)

enum `audio_stream_type_t`

  Values:

  `AUDIO_STREAM_NONE` = 0
  `AUDIO_STREAM_READER`
  `AUDIO_STREAM_WRITER`

enum `audio_codec_type_t`

  Values:

  `AUDIO_CODEC_TYPE_NONE` = 0
  `AUDIO_CODEC_TYPE_DECODER`
  `AUDIO_CODEC_TYPE_ENCODER`

#### ESP Audio

This component provides several simple high level APIs. It is intended for quick implementation of audio applications based on typical interconnections of standardized audio elements.

##### API Reference

###### Header File

- esp-adf-libs/esp_audio/include/audio_def.h

###### Structures

struct `esp_audio_state_t`

  esp_audio status information parameters

  Public Members

  esp_audio_status_t `status`

    Status of esp_audio

  audio_err_t `err_msg`

    Status is `AUDIO_STATUS_ERROR`, err_msg will be setup

  media_source_type_t `media_src`

    Media source type

###### Macros

`ESP_ERR_AUDIO_BASE`

  Starting number of ESP audio error codes

###### Type Definitions

typedef void (*`esp_audio_event_callback`)(esp_audio_state_t *audio, void *ctx)

typedef esp_err_t (*`audio_volume_set`)(void *hd, int vol)

typedef esp_err_t (*`audio_volume_get`)(void *hd, int *vol)

###### Enumerations

enum `audio_err_t`

  Values:

  `ESP_ERR_AUDIO_NO_ERROR` = ESP_OK
  `ESP_ERR_AUDIO_FAIL` = ESP_FAIL
  `ESP_ERR_AUDIO_NO_INPUT_STREAM` = ESP_ERR_AUDIO_BASE + 1
  `ESP_ERR_AUDIO_NO_OUTPUT_STREAM` = ESP_ERR_AUDIO_BASE + 2
  `ESP_ERR_AUDIO_NO_CODEC` = ESP_ERR_AUDIO_BASE + 3
  `ESP_ERR_AUDIO_HAL_FAIL` = ESP_ERR_AUDIO_BASE + 4
  `ESP_ERR_AUDIO_MEMORY_LACK` = ESP_ERR_AUDIO_BASE + 5
  `ESP_ERR_AUDIO_INVALID_URI` = ESP_ERR_AUDIO_BASE + 6
  `ESP_ERR_AUDIO_INVALID_PATH` = ESP_ERR_AUDIO_BASE + 7
  `ESP_ERR_AUDIO_INVALID_PARAMETER` = ESP_ERR_AUDIO_BASE + 8
  `ESP_ERR_AUDIO_NOT_READY` = ESP_ERR_AUDIO_BASE + 9
  `ESP_ERR_AUDIO_NOT_SUPPORT` = ESP_ERR_AUDIO_BASE + 10
  `ESP_ERR_AUDIO_TIMEOUT` = ESP_ERR_AUDIO_BASE + 11
  `ESP_ERR_AUDIO_ALREADY_EXISTS` = ESP_ERR_AUDIO_BASE + 12
  `ESP_ERR_AUDIO_LINK_FAIL` = ESP_ERR_AUDIO_BASE + 13
  `ESP_ERR_AUDIO_UNKNOWN` = ESP_ERR_AUDIO_BASE + 14
  `ESP_ERR_AUDIO_OUT_OF_RANGE` = ESP_ERR_AUDIO_BASE + 15
  `ESP_ERR_AUDIO_STOP_BY_USER` = ESP_ERR_AUDIO_BASE + 16
  `ESP_ERR_AUDIO_OPEN` = ESP_ERR_AUDIO_BASE + 0x100
  `ESP_ERR_AUDIO_INPUT` = ESP_ERR_AUDIO_BASE + 0x101
  `ESP_ERR_AUDIO_PROCESS` = ESP_ERR_AUDIO_BASE + 0x102
  `ESP_ERR_AUDIO_OUTPUT` = ESP_ERR_AUDIO_BASE + 0x103
  `ESP_ERR_AUDIO_CLOSE` = ESP_ERR_AUDIO_BASE + 0x104

enum `esp_audio_status_t`

  Values:

  `AUDIO_STATUS_UNKNOWN` = 0
  `AUDIO_STATUS_RUNNING` = 1
  `AUDIO_STATUS_PAUSED` = 2
  `AUDIO_STATUS_STOPPED` = 3
  `AUDIO_STATUS_FINISHED` = 4
  `AUDIO_STATUS_ERROR` = 5

enum `audio_termination_type_t`

  Values:

  `TERMINATION_TYPE_NOW` = 0

    Audio operation will be terminated immediately

  `TERMINATION_TYPE_DONE` = 1

    Audio operation will be stopped when finished

  `TERMINATION_TYPE_MAX`

enum `esp_audio_prefer_t`

  Values:

  `ESP_AUDIO_PREFER_MEM` = 0
  `ESP_AUDIO_PREFER_SPEED` = 1

enum `media_source_type_t`

  Values:

  `MEDIA_SRC_TYPE_NULL` = 0
  `MEDIA_SRC_TYPE_MUSIC_BASE` = 0x100
  `MEDIA_SRC_TYPE_MUSIC_SD` = MEDIA_SRC_TYPE_MUSIC_BASE + 1
  `MEDIA_SRC_TYPE_MUSIC_HTTP` = MEDIA_SRC_TYPE_MUSIC_BASE + 2
  `MEDIA_SRC_TYPE_MUSIC_FLASH` = MEDIA_SRC_TYPE_MUSIC_BASE + 3
  `MEDIA_SRC_TYPE_MUSIC_A2DP` = MEDIA_SRC_TYPE_MUSIC_BASE + 4
  `MEDIA_SRC_TYPE_MUSIC_DLNA` = MEDIA_SRC_TYPE_MUSIC_BASE + 5
  `MEDIA_SRC_TYPE_MUSIC_RAW` = MEDIA_SRC_TYPE_MUSIC_BASE + 6
  `MEDIA_SRC_TYPE_MUSIC_MAX` = 0x1FF
  `MEDIA_SRC_TYPE_TONE_BASE` = 0x200
  `MEDIA_SRC_TYPE_TONE_SD` = MEDIA_SRC_TYPE_TONE_BASE + 1
  `MEDIA_SRC_TYPE_TONE_HTTP` = MEDIA_SRC_TYPE_TONE_BASE + 2
  `MEDIA_SRC_TYPE_TONE_FLASH` = MEDIA_SRC_TYPE_TONE_BASE + 3
  `MEDIA_SRC_TYPE_TONE_MAX` = 0x2FF
  `MEDIA_SRC_TYPE_RESERVE_BASE` = 0x800
  `MEDIA_SRC_TYPE_RESERVE_MAX` = 0xFFF

###### Header File

- esp-adf-libs/esp_audio/include/esp_audio.h

###### Functions

esp_audio_handle_t `esp_audio_create`(const esp_audio_cfg_t *cfg)

  Create esp_audio instance according to ‘cfg’ parameter.

  This function create an esp_audio instance, at the specified configuration.

  Return

    - NULL: Error

    - Others: esp_audio instance fully certifying

  Parameters

    - `[in] cfg`: Provide esp_audio initialization configuration

audio_err_t `esp_audio_destroy`(esp_audio_handle_t handle)

  Specific esp_audio instance will be destroyed.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no instance to free, call esp_audio_init first

  Parameters

    - `[in] handle`: The esp_audio instance

audio_err_t `esp_audio_input_stream_add`(esp_audio_handle_t handle, audio_element_handle_t in_stream)

  Add audio input stream to specific esp_audio instance.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

    - ESP_ERR_AUDIO_MEMORY_LACK: allocate memory fail

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] in_stream`: Audio stream instance

audio_err_t `esp_audio_output_stream_add`(esp_audio_handle_t handle, audio_element_handle_t out_stream)

  Add audio output stream to specific esp_audio instance.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

    - ESP_ERR_AUDIO_MEMORY_LACK: allocate memory fail

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] out_stream`: The audio stream element instance

audio_err_t `esp_audio_codec_lib_add`(esp_audio_handle_t handle, audio_codec_type_t type, audio_element_handle_t lib)

  Add a new codec lib that can decode or encode a music file.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

    - ESP_ERR_AUDIO_MEMORY_LACK: allocate memory fail

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] type`: The audio codec type(encoder or decoder)

    - `[in] lib`: To provide audio stream element

audio_err_t `esp_audio_codec_lib_query`(esp_audio_handle_t handle, audio_codec_type_t type, const char *extension)

  Check if this kind of music extension is supported or not.

  Note

    This function just query the codec which has already add by esp_audio_codec_lib_add. The max length of extension is 6.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: supported

    - ESP_ERR_AUDIO_NOT_SUPPORT: not support

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] type`: The CODEC_ENCODER or CODEC_DECODER

    - `[in] extension`: Such as “mp3”, “wav”, “aac”

audio_err_t `esp_audio_play`(esp_audio_handle_t handle, audio_codec_type_t type, const char *uri, int pos)

  Play the given uri.

  The esp_audio_play have follow activity, setup inputstream, outputstream and codec by uri, start all of them. There is a rule that esp_audio will select input stream, codec and output stream by URI field.

  Rule of URI field are as follow.

  - `UF_SCHEMA` field of URI for choose input stream from existing streams. e.g:”http”,”file”

  - `UF_PATH` field of URI for choose codec from existing codecs. e.g:”/audio/mp3_music.mp3”

  - `UF_FRAGMENT` field of URI for choose output stream from existing streams, output stream is I2S by default.

  - `UF_USERINFO` field of URI for specific sample rate and channels at encode mode.

  The format “user:password” in the userinfo field, “user” is sample rate, “password” is channels.

  Now esp_audio_play support follow URIs.

  - ”https://dl.espressif.com/dl/audio/mp3_music.mp3”

  - ”http://media-ice.musicradio.com/ClassicFMMP3”

  - ”file://sdcard/test.mp3”

  - ”iis://16000:2@from.pcm/rec.wav#file”

  - ”iis://16000:1@record.pcm/record.wav#raw”

  - ”aadp://44100:2@bt/sink/stream.pcm”

  - ”hfp://8000:1@bt/hfp/stream.pcm”

  Note

    - The URI parse by `http_parser_parse_url`,any illegal string will be return `ESP_ERR_AUDIO_INVALID_URI`.

    - If the esp_decoder codec is added to `handle`, then the `handle` of esp_decoder will be set as the default decoder, even if other decoders are added.

    - Enabled `CONFIG_FATFS_API_ENCODING_UTF_8`, the URI can be support Chinese characters.

    - Asynchronous interface

    - The maximum of block time can be modify by `esp_audio_play_timeout_set`, default value is 25 seconds.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_TIMEOUT: timeout the play activity

    - ESP_ERR_AUDIO_NOT_SUPPORT: Currently status is AUDIO_STATUS_RUNNING

    - ESP_ERR_AUDIO_INVALID_URI: URI is illegal

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

    - ESP_ERR_AUDIO_STOP_BY_USER: Exit without play due to esp_audio_stop has been called.

  Parameters

    - `handle`: The esp_audio_handle_t instance

    - `uri`: Such as “file://sdcard/test.wav” or “http://iot.espressif.com/file/example.mp3”. If NULL to be set, the uri setup by`esp_audio_setup` will used.

    - `type`: Specific handle type decoder or encoder

    - `pos`: Specific starting position by bytes

audio_err_t `esp_audio_sync_play`(esp_audio_handle_t handle, const char *uri, int pos)

  Play the given uri until music finished or error occured.

  Note

    - All features are same with `esp_audio_play`

    - Synchronous interface

    - Support decoder mode only

    - No any events post during playing

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_TIMEOUT: timeout the play activity

    - ESP_ERR_AUDIO_NOT_SUPPORT: Currently status is AUDIO_STATUS_RUNNING

    - ESP_ERR_AUDIO_INVALID_URI: URI is illegal

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `handle`: The esp_audio_handle_t instance

    - `uri`: Such as “file://sdcard/test.wav” or “http://iot.espressif.com/file/example.mp3”,

    - `pos`: Specific starting position by bytes

audio_err_t `esp_audio_stop`(esp_audio_handle_t handle, audio_termination_type_t type)

  A synchronous interface for stop the esp_audio. The maximum of block time is 8000ms.

  Note

    1. If user queue has been registered by evt_que, AUDIO_STATUS_STOPPED event for success or AUDIO_STATUS_ERROR event for error will be received.

    1. `TERMINATION_TYPE_DONE` only works with input stream which can’t stopped by itself, e.g. `raw read/write stream`, others streams are no effect.

    2. The synchronous interface is used to ensure that working pipeline is stopped.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

    - ESP_ERR_AUDIO_NOT_READY: The status is not AUDIO_STATUS_RUNNING or AUDIO_STATUS_PAUSED or element has not created

    - ESP_ERR_AUDIO_TIMEOUT: timeout(8000ms) the stop activity.

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] type`: Stop immediately or done

audio_err_t `esp_audio_pause`(esp_audio_handle_t handle)

  Pause the esp_audio.

  Note

    1. Only support music and without live stream. If user queue has been registered by evt_que, AUDIO_STATUS_PAUSED event for success or AUDIO_STATUS_ERROR event for error will be received.

    1. The Paused music must be stoped by `esp_audio_stop` before new playing, otherwise got block on new play.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

    - ESP_ERR_AUDIO_NOT_READY: the status is not running

    - ESP_ERR_AUDIO_TIMEOUT: timeout the pause activity.

  Parameters

    - `[in] handle`: The esp_audio instance

audio_err_t `esp_audio_resume`(esp_audio_handle_t handle)

  Resume the music paused.

  Note

    Only support music and without live stream. If user queue has been registered by evt_que, AUDIO_STATUS_RUNNING event for success or AUDIO_STATUS_ERROR event for error will be received.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

    - ESP_ERR_AUDIO_TIMEOUT: timeout the resume activity.

  Parameters

    - `[in] handle`: The esp_audio instance

audio_err_t `esp_audio_eq_gain_set`(esp_audio_handle_t handle, int band_index, int nch, int eq_gain)

  Set the audio gain to be processed by the equalizer.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] band_index`: The position of center frequencies of equalizer. The range of eq band index is [0 - 9].

    - `[in] nch`: The number of channel. As for mono, the nch can only set to 1. As for dual, thc nch can set to 1 and 2.

    - `[in] eq_gain`: The value of audio gain which in `band_index`.

audio_err_t `esp_audio_eq_gain_get`(esp_audio_handle_t handle, int band_index, int nch, int *eq_gain)

  Get the audio gain to be processed by the equalizer.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: Audio element handle

    - `[in] band_index`: The position of center frequencies of equalizer. The range of eq band index is [0 - 9].

    - `[in] nch`: The number of channel. As for mono, the nch can only set to 1. As for dual, thc nch can set to 1 and 2.

    - `[out] eq_gain`: The pointer of the gain processed by equalizer

audio_err_t `esp_audio_speed_get`(esp_audio_handle_t handle, esp_audio_play_speed_t *speed_index)

  Getting esp_audio play speed index, index value is from “esp_audio_speed_t” enum.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] speed_index`: Current audio play speed index.

audio_err_t `esp_audio_speed_set`(esp_audio_handle_t handle, esp_audio_play_speed_t speed_index)

  Use speed_index which is from “esp_audio_speed_t” enum to set esp_audio play speed.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] speed_index`: Value from “esp_audio_speed_t” enum.

audio_err_t `esp_audio_speed_idx_to_float`(esp_audio_handle_t handle, esp_audio_play_speed_t speed_index, float *speed)

  Use speed_index which is from “esp_audio_speed_t” enum to get esp_audio play speed which is float type.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] speed_index`: Current audio play speed index.

    - `[out] speed`: Current audio play speed.

audio_err_t `esp_audio_vol_set`(esp_audio_handle_t handle, int vol)

  Setting esp_audio volume.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_CTRL_HAL_FAIL: error with hardware.

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] vol`: Specific volume will be set. 0-100 is legal. 0 will be mute.

audio_err_t `esp_audio_vol_get`(esp_audio_handle_t handle, int *vol)

  Get esp_audio volume.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_CTRL_HAL_FAIL: error with hardware.

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] vol`: A pointer to int that indicates esp_audio volume.

audio_err_t `esp_audio_state_get`(esp_audio_handle_t handle, esp_audio_state_t *state)

  Get esp_audio status.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance or esp_audio does not playing

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] state`: A pointer to esp_audio_state_t that indicates esp_audio status.

audio_err_t `esp_audio_pos_get`(esp_audio_handle_t handle, int *pos)

  Get the position in bytes of currently played music.

  Note

    This function works only with decoding music.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance

    - ESP_ERR_AUDIO_NOT_READY: no codec element

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] pos`: A pointer to int that indicates esp_audio decoding position.

audio_err_t `esp_audio_time_get`(esp_audio_handle_t handle, int *time)

  Get the position in microseconds of currently played music.

  Note

    This function works only with decoding music.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance

    - ESP_ERR_AUDIO_NOT_READY: no out stream

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] time`: A pointer to int that indicates esp_audio decoding position.

audio_err_t `esp_audio_setup`(esp_audio_handle_t handle, esp_audio_setup_t *sets)

  Choose the `in_stream`, `codec` and `out_stream` definitely, and set `uri`.

  Note

    This function provide a manual way to select in/out stream and codec, should be called before the `esp_audio_play`, then ignore the `esp_audio_play` URI parameter only one time.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance

    - ESP_ERR_AUDIO_MEMORY_LACK: allocate memory fail

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] sets`: A pointer to esp_audio_setup_t.

audio_err_t `esp_audio_media_type_set`(esp_audio_handle_t handle, media_source_type_t type)

audio_err_t `esp_audio_music_info_get`(esp_audio_handle_t handle, esp_audio_music_info_t *info)

audio_err_t `esp_audio_info_get`(esp_audio_handle_t handle, esp_audio_info_t *info)

audio_err_t `esp_audio_info_set`(esp_audio_handle_t handle, esp_audio_info_t *info)

audio_err_t `esp_audio_callback_set`(esp_audio_handle_t handle, esp_audio_event_callback cb, void *cb_ctx)

audio_err_t `esp_audio_seek`(esp_audio_handle_t handle, int seek_time_sec)

  Seek the position in second of currently played music.

  Note

    This function works only with decoding music.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_FAIL: codec or allocation fail

    - ESP_ERR_AUDIO_TIMEOUT: timeout for sync the element status

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance

    - ESP_ERR_AUDIO_NOT_SUPPORT: codec has finished

    - ESP_ERR_AUDIO_OUT_OF_RANGE: the seek_time_ms is out of the range

    - ESP_ERR_AUDIO_NOT_READY: the status is neither running nor paused

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] seek_time_sec`: A pointer to int that indicates esp_audio decoding position.

audio_err_t `esp_audio_duration_get`(esp_audio_handle_t handle, int *duration)

  Get the duration in microseconds of playing music.

  Note

    This function works only with decoding music.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance

    - ESP_ERR_AUDIO_NOT_READY: no codec element or no in element

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] duration`: A pointer to int that indicates decoding total time.

audio_err_t `esp_audio_play_timeout_set`(esp_audio_handle_t handle, int time_ms)

  Setting the maximum amount of time to waiting for `esp_audio_play` only.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[in] time_ms`: The maximum amount of time

audio_err_t `esp_audio_prefer_type_get`(esp_audio_handle_t handle, esp_audio_prefer_t *type)

  Get the type of `esp_audio_prefer_t`

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] type`: A pointer to esp_audio_prefer_t

audio_err_t `esp_audio_event_que_set`(esp_audio_handle_t handle, QueueHandle_t que)

  Set event queue to notify the esp_audio status.

  Return

    - ESP_ERR_AUDIO_NO_ERROR: on success

    - ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance

  Parameters

    - `[in] handle`: The esp_audio instance

    - `[out] que`: A pointer to QueueHandle_t

###### Structures

struct `esp_audio_cfg_t`

  esp_audio configuration parameters

  Public Members

  int `in_stream_buf_size`

    Input buffer size

  int `out_stream_buf_size`

    Output buffer size

  int `resample_rate`

    Destination sample rate, 0: disable resample; others: 44.1K, 48K, 32K, 16K, 8K has supported It should be make sure same with I2S stream `sample_rate`

  int `component_select`

    The select of audio forge component. eg. To choose equalizer and ALC together, please enter ESP_AUDIO_COMPONENT_SELECT_ALC | ESP_AUDIO_COMPONENT_SELECT_EQUALIZER.

  QueueHandle_t `evt_que`

    For received esp_audio events (optional)

  esp_audio_event_callback `cb_func`

    esp_audio events callback (optional)

  void *`cb_ctx`

    esp_audio callback context (optional)

  esp_audio_prefer_t `prefer_type`

    esp_audio works on sepcific type, default memory is preferred.

    - `ESP_AUDIO_PREFER_MEM` mode stopped the previous linked elements before the new pipeline starting, except out stream element.

    - `ESP_AUDIO_PREFER_SPEED` mode kept the previous linked elements before the new pipeline starting, except out stream element.

  void *`vol_handle`

    Volume change instance

  audio_volume_set `vol_set`

    Set volume callback

  audio_volume_get `vol_get`

    Get volume callback

  int `task_prio`

    esp_audio task priority

  int `task_stack`

    Size of esp_audio task stack

struct `esp_audio_setup_t`

  esp_audio setup parameters by manual

  Public Members

  audio_codec_type_t `set_type`

    Set codec type

  int `set_sample_rate`

    Set music sample rate

  int `set_channel`

    Set music channels

  int `set_pos`

    Set starting position

  int `set_time`

    Set starting position of the microseconds time (optional)

  char *`set_uri`

    Set URI

  char *`set_in_stream`

    Tag of in_stream

  char *`set_codec`

    Tag of the codec

  char *`set_out_stream`

    Tag of out_stream

struct `esp_audio_info_t`

  esp_audio information

  Public Members

  audio_element_info_t `codec_info`

    Codec information

  audio_element_handle_t `in_el`

    Handle of the in stream

  audio_element_handle_t `out_el`

    Handle of the out stream

  audio_element_handle_t `codec_el`

    Handle of the codec

  audio_element_handle_t `filter_el`

    Handle of the filter

  esp_audio_state_t `st`

    The state of esp_audio

  int `time_pos`

    Position of the microseconds time

  float `audio_speed`

    Play speed of audio

  int64_t `in_stream_total_size`

    Total size of in stream

struct `esp_audio_music_info_t`

  The music informations.

  Public Members

  int `sample_rates`

    Sample rates in Hz

  int `channels`

    Number of audio channel, mono is 1, stereo is 2

  int `bits`

    Bit wide (8, 16, 24, 32 bits)

  int `bps`

    Bit per second

  esp_codec_type_t `codec_fmt`

    Music format

###### Macros

`ESP_AUDIO_COMPONENT_SELECT_DEFAULT`

  Default selected

`ESP_AUDIO_COMPONENT_SELECT_ALC`

  ALC selected

`ESP_AUDIO_COMPONENT_SELECT_EQUALIZER`

  Equalizer selected

`DEFAULT_ESP_AUDIO_CONFIG`()

###### Type Definitions

typedef void *`esp_audio_handle_t`

###### Enumerations

enum `esp_audio_play_speed_t`

  esp_audio play speed

  Values:

  `ESP_AUDIO_PLAY_SPEED_UNKNOW` = -1
  `ESP_AUDIO_PLAY_SPEED_0_50` = 0
  `ESP_AUDIO_PLAY_SPEED_0_75` = 1
  `ESP_AUDIO_PLAY_SPEED_1_00` = 2
  `ESP_AUDIO_PLAY_SPEED_1_25` = 3
  `ESP_AUDIO_PLAY_SPEED_1_50` = 4
  `ESP_AUDIO_PLAY_SPEED_1_75` = 5
  `ESP_AUDIO_PLAY_SPEED_2_00` = 6
  `ESP_AUDIO_PLAY_SPEED_MAX` = 7

### Audio Streams

[中文]

The Audio Stream refers to an Audio Element that is responsible for acquiring of audio data and then sending the data out after processing.

The following stream types are supported:

- Algorithm Stream

- FatFs Stream

- HTTP Stream

- I2S Stream

- PWM Stream

- Raw Stream

- SPIFFS Stream

- TCP Client Stream

- Tone Stream

- Flash-Embedding Stream

- TTS Stream

Each stream is initialized with a structure as an input, and the returned `audio_element_handle_t` handle is used to call the functions in `audio_element.h`. Most streams have two types, `AUDIO_STREAM_READER` (reader) and `AUDIO_STREAM_WRITER` (writer). For example, to set the I2S stream type, use `i2s_stream_init()` and `i2s_stream_cfg_t`.

See description below for the API details.

#### Algorithm Stream

The algorithm stream integrates front-end algorithms such as acoustic echo cancellation (AEC), automatic gain control (AGC), and noise suppression (NS) to process the received audio. It is often used in audio preprocessing scenarios, including VoIP, speech recognition, and keyword wake-up. The stream calls esp-sr and thus occupies large memory. The stream only supports the `AUDIO_STREAM_READER` type.

##### Application Example

- advanced_examples/algorithm/main/algorithm_examples.c

- protocols/voip/main/voip_app.c

##### Header File

- audio_stream/include/algorithm_stream.h

##### Functions

audio_element_handle_t `algo_stream_init`(algorithm_stream_cfg_t *config)

  Initialize algorithm stream.

  Return

    The audio element handle

  Parameters

    - `config`: The algorithm Stream configuration

audio_element_err_t `algo_stream_set_delay`(audio_element_handle_t el, ringbuf_handle_t ringbuf, int delay_ms)

  Set playback signal or recording signal delay when use type2.

  Note

    The AEC internal buffering mechanism requires that the recording signal is delayed by around 0 - 10 ms compared to the corresponding reference (playback) signal.

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `el`: Handle of element

    - `ringbuf`: Handle of ringbuf

    - `delay_ms`: The delay between playback and recording in ms This delay_ms can be debugged by yourself, you can set the configuration debug_input to true, then get the original input data (left channel is the signal captured from the microphone, right channel is the signal played to the speaker), and check the delay with an audio analysis tool.

esp_err_t `algorithm_mono_fix`(uint8_t *sbuff, uint32_t len)

  Fix I2S mono noise issue.

  Note

    This API only for ESP32 with I2S 16bits

  Return

    ESP_OK

  Parameters

    - `sbuff`: I2S data buffer

    - `len`: I2S data len

##### Structures

struct `algorithm_stream_cfg_t`

  Algorithm stream configurations.

  Public Members

  algorithm_stream_input_type_t `input_type`

    Input type of stream

  int `task_stack`

    Task stack size

  int `task_prio`

    Task peroid

  int `task_core`

    The core that task to be created

  int `out_rb_size`

    Size of output ringbuffer

  bool `stack_in_ext`

    Try to allocate stack in external memory

  int `rec_linear_factor`

    The linear amplication factor of record signal

  int `ref_linear_factor`

    The linear amplication factor of reference signal

  bool `debug_input`

    debug algorithm input data

  bool `swap_ch`

    Swap left and right channels

  int8_t `algo_mask`

    Choose algorithm to use

  int `sample_rate`

    The sampling rate of the input PCM (in Hz)

  int `mic_ch`

    MIC channel num

  int `agc_gain`

    AGC gain(dB) for voice communication

  bool `aec_low_cost`

    AEC uses less cpu and ram resources, but has poor suppression of nonlinear distortion

  char *`partition_label`

    Partition label which stored the model data

##### Macros

`ALGORITHM_STREAM_PINNED_TO_CORE`

`ALGORITHM_STREAM_TASK_PERIOD`

`ALGORITHM_STREAM_RINGBUFFER_SIZE`

`ALGORITHM_STREAM_TASK_STACK_SIZE`

`ALGORITHM_STREAM_DEFAULT_SAMPLE_RATE_HZ`

`ALGORITHM_STREAM_DEFAULT_SAMPLE_BIT`

`ALGORITHM_STREAM_DEFAULT_MIC_CHANNELS`

`ALGORITHM_STREAM_DEFAULT_AGC_GAIN_DB`

`ALGORITHM_STREAM_DEFAULT_MASK`

`ALGORITHM_STREAM_CFG_DEFAULT`()

##### Enumerations

enum `algorithm_stream_input_type_t`

  Two types of algorithm stream input method.

  Values:

  `ALGORITHM_STREAM_INPUT_TYPE1` = 0

    Type 1 is default used by mini-board, the reference signal and the recording signal are respectively read in from the left channel and the right channel of the same I2S

  `ALGORITHM_STREAM_INPUT_TYPE2` = 1

    As the simple diagram above shows, when type2 is choosen, the recording signal and reference signal should be input by users.

enum `algorithm_stream_mask_t`

  Choose the algorithm to be used.

  Values:

  `ALGORITHM_STREAM_USE_AEC` = (0x1 << 0)

    Use AEC

  `ALGORITHM_STREAM_USE_AGC` = (0x1 << 1)

    Use AGC

  `ALGORITHM_STREAM_USE_NS` = (0x1 << 2)

    Use NS

  `ALGORITHM_STREAM_USE_VAD` = (0x1 << 3)

    Use VAD

#### FatFs Stream

The FatFs stream reads and writes data from FatFs. It has two types: “reader” and “writer”. The type is defined by `audio_stream_type_t`.

##### Application Example

- Reader example: player/pipeline_play_sdcard_music

- Writer example: recorder/pipeline_recording_to_sdcard

##### Header File

- audio_stream/include/fatfs_stream.h

##### Functions

audio_element_handle_t `fatfs_stream_init`(fatfs_stream_cfg_t *config)

  Create a handle to an Audio Element to stream data from FatFs to another Element or get data from other elements written to FatFs, depending on the configuration the stream type, either AUDIO_STREAM_READER or AUDIO_STREAM_WRITER.

  Return

    The Audio Element handle

  Parameters

    - `config`: The configuration

##### Structures

struct `fatfs_stream_cfg_t`

  FATFS Stream configurations, if any entry is zero then the configuration will be set to default values.

  Public Members

  audio_stream_type_t `type`

    Stream type

  int `buf_sz`

    Audio Element Buffer size

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `ext_stack`

    Allocate stack on extern ram

  bool `write_header`

    Choose to write amrnb/amrwb header in fatfs whether or not (true or false, true means choose to write amrnb header)

##### Macros

`FATFS_STREAM_BUF_SIZE`

`FATFS_STREAM_TASK_STACK`

`FATFS_STREAM_TASK_CORE`

`FATFS_STREAM_TASK_PRIO`

`FATFS_STREAM_RINGBUFFER_SIZE`

`FATFS_STREAM_CFG_DEFAULT`()

#### HTTP Stream

The HTTP stream obtains and sends data through `esp_http_client()`. The stream has two types: “reader” and “writer”, and the type is defined by `audio_stream_type_t`. `AUDIO_STREAM_READER` supports HTTP, HTTPS, HTTP Live Stream, and other protocols. Make sure the network is connected before using the stream.

##### Application Example

- Reader example

  - player/pipeline_living_stream

  - player/pipeline_http_mp3

- Writer example

  - recorder/pipeline_raw_http

##### Header File

- audio_stream/include/http_stream.h

##### Functions

audio_element_handle_t `http_stream_init`(http_stream_cfg_t *config)

  Create a handle to an Audio Element to stream data from HTTP to another Element or get data from other elements sent to HTTP, depending on the configuration the stream type, either AUDIO_STREAM_READER or AUDIO_STREAM_WRITER.

  Return

    The Audio Element handle

  Parameters

    - `config`: The configuration

esp_err_t `http_stream_next_track`(audio_element_handle_t el)

  Connect to next track in the playlist.

              This function can be used in event_handler of http_stream.
              User can call this function to connect to next track in playlist when he/she gets `HTTP_STREAM_FINISH_TRACK` event

  Return

    - ESP_OK on success

    - ESP_FAIL on errors

  Parameters

    - `el`: The http_stream element handle

esp_err_t `http_stream_restart`(audio_element_handle_t el)

esp_err_t `http_stream_fetch_again`(audio_element_handle_t el)

  Try to fetch the tracks again.

               If this is live stream we will need to keep fetching URIs.

  Return

    - ESP_OK on success

    - ESP_ERR_NOT_SUPPORTED if playlist is finished

  Parameters

    - `el`: The http_stream element handle

esp_err_t `http_stream_set_server_cert`(audio_element_handle_t el, const char *cert)

  Set SSL server certification.

  Note

    EM format as string, if the client requires to verify server

  Return

    - ESP_OK on success

  Parameters

    - `el`: The http_stream element handle

    - `cert`: server certification

##### Structures

struct `http_stream_event_msg_t`

  Stream event message.

  Public Members

  http_stream_event_id_t `event_id`

    Event ID

  void *`http_client`

    Reference to HTTP Client using by this HTTP Stream

  void *`buffer`

    Reference to Buffer using by the Audio Element

  int `buffer_len`

    Length of buffer

  void *`user_data`

    User data context, from `http_stream_cfg_t`

  audio_element_handle_t `el`

    Audio element context

struct `http_stream_cfg_t`

  HTTP Stream configurations Default value will be used if any entry is zero.

  Public Members

  audio_stream_type_t `type`

    Type of stream

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

  http_stream_event_handle_t `event_handle`

    The hook function for HTTP Stream

  void *`user_data`

    User data context

  bool `auto_connect_next_track`

    connect next track without open/close

  bool `enable_playlist_parser`

    Enable playlist parser

  int `multi_out_num`

    The number of multiple output

  const char *`cert_pem`

    SSL server certification, PEM format as string, if the client requires to verify server

  esp_err_t (*`crt_bundle_attach`)(void *conf)

    Function pointer to esp_crt_bundle_attach. Enables the use of certification bundle for server verification, must be enabled in menuconfig

  int `request_size`

    Request data size each time from `http_client` Defaults use DEFAULT_ELEMENT_BUFFER_LENGTH if set to 0 Need care this setting if audio frame size is small and want low latency playback

  int `request_range_size`

    Range size setting for header `Range: bytes=start-end` Request full range of resource if set to 0 Range size bigger than request size is recommended

  const char *`user_agent`

    The User Agent string to send with HTTP requests

##### Macros

`HTTP_STREAM_TASK_STACK`

`HTTP_STREAM_TASK_CORE`

`HTTP_STREAM_TASK_PRIO`

`HTTP_STREAM_RINGBUFFER_SIZE`

`HTTP_STREAM_CFG_DEFAULT`()

##### Type Definitions

typedef int (*`http_stream_event_handle_t`)(http_stream_event_msg_t *msg)

##### Enumerations

enum `http_stream_event_id_t`

  HTTP Stream hook type.

  Values:

  `HTTP_STREAM_PRE_REQUEST` = 0x01

    The event handler will be called before HTTP Client making the connection to the server

  `HTTP_STREAM_ON_REQUEST`

    The event handler will be called when HTTP Client is requesting data, If the fucntion return the value (-1: ESP_FAIL), HTTP Client will be stopped If the fucntion return the value > 0, HTTP Stream will ignore the post_field If the fucntion return the value = 0, HTTP Stream continue send data from post_field (if any)

  `HTTP_STREAM_ON_RESPONSE`

    The event handler will be called when HTTP Client is receiving data If the fucntion return the value (-1: ESP_FAIL), HTTP Client will be stopped If the fucntion return the value > 0, HTTP Stream will ignore the read function If the fucntion return the value = 0, HTTP Stream continue read data from HTTP Server

  `HTTP_STREAM_POST_REQUEST`

    The event handler will be called after HTTP Client send header and body to the server, before fetching the headers

  `HTTP_STREAM_FINISH_REQUEST`

    The event handler will be called after HTTP Client fetch the header and ready to read HTTP body

  `HTTP_STREAM_RESOLVE_ALL_TRACKS`
  `HTTP_STREAM_FINISH_TRACK`
  `HTTP_STREAM_FINISH_PLAYLIST`

#### I2S Stream

The I2S stream receives and transmits audio data through the chip’s I2S, PDM, ADC, and DAC interfaces. To use the ADC and DAC functions, the chip needs to define `SOC_I2S_SUPPORTS_ADC_DAC`. The stream integrates automatic level control (ALC) to adjust volume, multi-channel output, and sending audio data with extended bit width. The relevant control bits are defined in `i2s_stream_cfg_t`.

##### Application Example

- Reader example: recorder/pipeline_wav_amr_sdcard

- Writer example: get-started/play_mp3_control

##### Header File

- audio_stream/include/i2s_stream.h

##### Functions

audio_element_handle_t `i2s_stream_init`(i2s_stream_cfg_t *config)

  Create a handle to an Audio Element to stream data from I2S to another Element or get data from other elements sent to I2S, depending on the configuration of stream type is AUDIO_STREAM_READER or AUDIO_STREAM_WRITER.

  Note

    If I2S stream is enabled with built-in DAC mode, please don’t use I2S_NUM_1. The built-in DAC functions are only supported on I2S0 for the current ESP32 chip.

  Return

    The Audio Element handle

  Parameters

    - `config`: The configuration

esp_err_t `i2s_stream_set_channel_type`(i2s_stream_cfg_t *config, i2s_channel_type_t type)

  Set I2S stream channel format type.

  Note

    : This function only updates i2s_stream_cfg_t, so it needs to be called before i2s_stream_init.

  Return

    - ESP_OK

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] config`: The I2S stream configuration

    - `[in] type`: I2S channel format type

esp_err_t `i2s_stream_set_clk`(audio_element_handle_t i2s_stream, int rate, int bits, int ch)

  Setup clock for I2S Stream, this function is only used with handle created by `i2s_stream_init`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] i2s_stream`: The i2s element handle

    - `[in] rate`: Clock rate (in Hz)

    - `[in] bits`: Audio bit width (8, 16, 24, 32)

    - `[in] ch`: Number of Audio channels (1: Mono, 2: Stereo). But when set to tdm mode, ch is slot mask.(ex: I2S_TDM_SLOT0 | I2S_TDM_SLOT1 | I2S_TDM_SLOT2 | I2S_TDM_SLOT3)

esp_err_t `i2s_alc_volume_set`(audio_element_handle_t i2s_stream, int volume)

  Set the volume of input audio stream with ALC. Positive value indicates an increase in volume, negative value indicates a decrease in volume, 0 indicates the volume level remains unchanged.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] i2s_stream`: The i2s element handle

    - `[in] volume`: The gain of input audio stream:

      - Supported range [-64, 63], unit: dB

esp_err_t `i2s_alc_volume_get`(audio_element_handle_t i2s_stream, int *volume)

  Get volume of stream.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] i2s_stream`: The i2s element handle

    - `[in] volume`: The volume of stream

esp_err_t `i2s_stream_sync_delay`(audio_element_handle_t i2s_stream, int delay_ms)

  Set sync delay of stream.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] i2s_stream`: The i2s element handle

    - `[in] delay_ms`: The delay of stream

##### Structures

struct `i2s_stream_cfg_t`

  I2S Stream configurations Default value will be used if any entry is zero.

  Public Members

  audio_stream_type_t `type`

    Type of stream

  i2s_comm_mode_t `transmit_mode`

    I2S transmit mode

  i2s_chan_config_t `chan_cfg`

    I2S controller channel configuration

  i2s_std_config_t `std_cfg`

    I2S standard mode major configuration that including clock/slot/gpio configuration

  i2s_data_bit_width_t `expand_src_bits`

    The source bits per sample when data expand

  bool `use_alc`

    It is a flag for ALC. If use ALC, the value is true. Or the value is false

  int `volume`

    The volume of audio input data will be set.

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

  int `multi_out_num`

    The number of multiple output

  bool `uninstall_drv`

    whether uninstall the i2s driver when stream destroyed

  bool `need_expand`

    whether to expand i2s data

  int `buffer_len`

    Buffer length use for an Element. Note: when ‘bits_per_sample’ is 24 bit, the buffer length must be a multiple of 3. The recommended value is 3600

##### Macros

`I2S_STREAM_TASK_STACK`

`I2S_STREAM_BUF_SIZE`

`I2S_STREAM_TASK_PRIO`

`I2S_STREAM_TASK_CORE`

`I2S_STREAM_RINGBUFFER_SIZE`

`I2S_STREAM_CFG_DEFAULT`()

`I2S_STREAM_CFG_DEFAULT_WITH_PARA`(port, rate, bits, stream_type)

##### Enumerations

enum `i2s_channel_type_t`

  Values:

  `I2S_CHANNEL_TYPE_RIGHT_LEFT`

    Separated left and right channel

  `I2S_CHANNEL_TYPE_ALL_RIGHT`

    Load right channel data in both two channels

  `I2S_CHANNEL_TYPE_ALL_LEFT`

    Load left channel data in both two channels

  `I2S_CHANNEL_TYPE_ONLY_RIGHT`

    Only load data in right channel (mono mode)

  `I2S_CHANNEL_TYPE_ONLY_LEFT`

    Only load data in left channel (mono mode)

#### PWM Stream

In some cost-sensitive scenarios, the audio signal is not converted by the DAC but is modulated by the PWM (pulse width modulation) and then implemented by a filter circuit. The PWM stream modulates the audio signal with the chip’s PWM and sends out the processed audio. It only has the `AUDIO_STREAM_WRITER` type. Note that the digital-to-analog conversion by PWM has a lower signal-to-noise ratio.

##### Application Example

- Writer example: player/pipeline_play_mp3_with_dac_or_pwm

##### Header File

- audio_stream/include/pwm_stream.h

##### Functions

audio_element_handle_t `pwm_stream_init`(pwm_stream_cfg_t *config)

  Initialize PWM stream Only support AUDIO_STREAM_READER type.

  Return

    The audio element handle

  Parameters

    - `config`: The PWM Stream configuration

esp_err_t `pwm_stream_set_clk`(audio_element_handle_t pwm_stream, int rate, int bits, int ch)

  Setup clock for PWM Stream, this function is only used with handle created by `pwm_stream_init`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] pwm_stream`: The pwm element handle

    - `[in] rate`: Clock rate (in Hz)

    - `[in] bits`: Audio bit width (16, 32)

    - `[in] ch`: Number of Audio channels (1: Mono, 2: Stereo)

##### Structures

struct `audio_pwm_config_t`

  PWM audio configurations.

  Public Members

  timer_group_t `tg_num`

    timer group number (0 - 1)

  timer_idx_t `timer_num`

    timer number (0 - 1)

  int `gpio_num_left`

    the LEDC output gpio_num, Left channel

  int `gpio_num_right`

    the LEDC output gpio_num, Right channel

  ledc_channel_t `ledc_channel_left`

    LEDC channel (0 - 7), Corresponding to left channel

  ledc_channel_t `ledc_channel_right`

    LEDC channel (0 - 7), Corresponding to right channel

  ledc_timer_t `ledc_timer_sel`

    Select the timer source of channel (0 - 3)

  ledc_timer_bit_t `duty_resolution`

    ledc pwm bits

  uint32_t `data_len`

    ringbuffer size

struct `pwm_stream_cfg_t`

  PWM Stream configurations Default value will be used if any entry is zero.

  Public Members

  audio_stream_type_t `type`

    Type of stream

  audio_pwm_config_t `pwm_config`

    driver configurations

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  int `buffer_len`

    pwm_stream buffer length

  bool `ext_stack`

    Allocate stack on extern ram

##### Macros

`PWM_STREAM_GPIO_NUM_LEFT`

`PWM_STREAM_GPIO_NUM_RIGHT`

`PWM_STREAM_TASK_STACK`

`PWM_STREAM_BUF_SIZE`

`PWM_STREAM_TASK_PRIO`

`PWM_STREAM_TASK_CORE`

`PWM_STREAM_RINGBUFFER_SIZE`

`PWM_CONFIG_RINGBUFFER_SIZE`

`PWM_STREAM_CFG_DEFAULT`()

#### Raw Stream

The raw stream is used to obtain the output data of the previous element of the connection or to provide the data for the next element of the connection. It does not create a thread. For `AUDIO_STREAM_READER`, the connection is [i2s] -> [filter] -> [raw] or [i2s] -> [codec-amr] -> [raw]. For `AUDIO_STREAM_WRITER`, the connection is [raw] ->[codec-mp3]->[i2s].

##### Application Example

- Reader example: protocols/voip

- Writer example: advanced_examples/downmix_pipeline

##### Header File

- audio_stream/include/raw_stream.h

##### Functions

audio_element_handle_t `raw_stream_init`(raw_stream_cfg_t *cfg)

  Initialize RAW stream.

  Return

    The audio element handle

  Parameters

    - `cfg`: The RAW Stream configuration

int `raw_stream_read`(audio_element_handle_t pipeline, char *buffer, int buf_size)

  Read data from Stream.

  Return

    Number of bytes actually read.

  Parameters

    - `pipeline`: The audio pipeline handle

    - `buffer`: The buffer

    - `buf_size`: Maximum number of bytes to be read.

int `raw_stream_write`(audio_element_handle_t pipeline, char *buffer, int buf_size)

  Write data to Stream.

  Return

    Number of bytes written

  Parameters

    - `pipeline`: The audio pipeline handle

    - `buffer`: The buffer

    - `buf_size`: Number of bytes to write

##### Structures

struct `raw_stream_cfg_t`

  Raw stream provides APIs to obtain the pipeline data without output stream or fill the pipeline data without input stream. The stream has two types / modes, reader and writer:

  - AUDIO_STREAM_READER, e.g. [i2s]->[filter]->[raw],[i2s]->[codec-amr]->[raw]

  - AUDIO_STREAM_WRITER, e.g. [raw]->[codec-mp3]->[i2s] Raw Stream configurations

  Public Members

  audio_stream_type_t `type`

    Type of stream

  int `out_rb_size`

    Size of output ringbuffer

##### Macros

`RAW_STREAM_RINGBUFFER_SIZE`

`RAW_STREAM_CFG_DEFAULT`()

#### SPIFFS Stream

The SPIFFS stream reads and writes audio data from or into SPIFFS.

##### Application Example

- player/pipeline_spiffs_mp3

##### Header File

- audio_stream/include/spiffs_stream.h

##### Functions

audio_element_handle_t `spiffs_stream_init`(spiffs_stream_cfg_t *config)

  Create a handle to an Audio Element to stream data from SPIFFS to another Element or get data from other elements written to SPIFFS, depending on the configuration the stream type, either AUDIO_STREAM_READER or AUDIO_STREAM_WRITER.

  Return

    The Audio Element handle

  Parameters

    - `config`: The configuration

##### Structures

struct `spiffs_stream_cfg_t`

  SPIFFS Stream configuration, if any entry is zero then the configuration will be set to default values.

  Public Members

  audio_stream_type_t `type`

    Stream type

  int `buf_sz`

    Audio Element Buffer size

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `write_header`

    Choose to write amrnb/armwb header in spiffs whether or not (true or false, true means choose to write amrnb header)

##### Macros

`SPIFFS_STREAM_BUF_SIZE`

`SPIFFS_STREAM_TASK_STACK`

`SPIFFS_STREAM_TASK_CORE`

`SPIFFS_STREAM_TASK_PRIO`

`SPIFFS_STREAM_RINGBUFFER_SIZE`

`SPIFFS_STREAM_CFG_DEFAULT`()

#### TCP Client Stream

The TCP client stream reads and writes server data over TCP.

##### Application Example

- get-started/pipeline_tcp_client

##### Header File

- audio_stream/include/tcp_client_stream.h

##### Functions

audio_element_handle_t `tcp_stream_init`(tcp_stream_cfg_t *config)

  Initialize a TCP stream to/from an audio element This function creates a TCP stream to/from an audio element depending on the stream type configuration (e.g., AUDIO_STREAM_READER or AUDIO_STREAM_WRITER). The handle of the audio element is the returned.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

##### Structures

struct `tcp_stream_event_msg`

  TCP Stream massage configuration.

  Public Members

  void *`source`

    Element handle

  void *`data`

    Data of input/output

  int `data_len`

    Data length of input/output

  esp_transport_handle_t `sock_fd`

    handle of socket

struct `tcp_stream_cfg_t`

  TCP Stream configuration, if any entry is zero then the configuration will be set to default values.

  Public Members

  audio_stream_type_t `type`

    Type of stream

  int `timeout_ms`

    time timeout for read/write

  int `port`

    TCP port>

  char *`host`

    TCP host>

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `ext_stack`

    Allocate stack on extern ram

  tcp_stream_event_handle_cb `event_handler`

    TCP stream event callback

  void *`event_ctx`

    User context

##### Macros

`TCP_STREAM_DEFAULT_PORT`

  TCP stream parameters.

`TCP_STREAM_TASK_STACK`

`TCP_STREAM_BUF_SIZE`

`TCP_STREAM_TASK_PRIO`

`TCP_STREAM_TASK_CORE`

`TCP_SERVER_DEFAULT_RESPONSE_LENGTH`

`TCP_STREAM_CFG_DEFAULT`()

##### Type Definitions

typedef struct tcp_stream_event_msg `tcp_stream_event_msg_t`

  TCP Stream massage configuration.

typedef esp_err_t (*`tcp_stream_event_handle_cb`)(tcp_stream_event_msg_t *msg, tcp_stream_status_t state, void *event_ctx)

##### Enumerations

enum `tcp_stream_status_t`

  Values:

  `TCP_STREAM_STATE_NONE`
  `TCP_STREAM_STATE_CONNECTED`

#### Tone Stream

The tone stream reads the data generated by tools/audio_tone/mk_audio_tone.py. It only supports the `AUDIO_STREAM_READER` type.

##### Application Example

- player/pipeline_flash_tone

##### Header File

- audio_stream/include/tone_stream.h

##### Functions

audio_element_handle_t `tone_stream_init`(tone_stream_cfg_t *config)

  Create an Audio Element handle to stream data from flash to another Element, only support AUDIO_STREAM_READER type.

  Return

    The Audio Element handle

  Parameters

    - `config`: The configuration

##### Structures

struct `tone_stream_cfg_t`

  TONE Stream configurations, if any entry is zero then the configuration will be set to default values.

  Public Members

  audio_stream_type_t `type`

    Stream type

  int `buf_sz`

    Audio Element Buffer size

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  const char *`label`

    Label of tone stored in flash. The default value is `flash_tone`

  bool `extern_stack`

    Task stack allocate on the extern ram

  bool `use_delegate`

    Read tone partition with esp_delegate. If task stack is on extern ram, this MUST be TRUE

##### Macros

`TONE_STREAM_BUF_SIZE`

`TONE_STREAM_TASK_STACK`

`TONE_STREAM_TASK_CORE`

`TONE_STREAM_TASK_PRIO`

`TONE_STREAM_RINGBUFFER_SIZE`

`TONE_STREAM_EXT_STACK`

`TONE_STREAM_USE_DELEGATE`

`TONE_STREAM_CFG_DEFAULT`()

#### Flash-Embedding Stream

The flash-embedding stream reads the data generated by tools/audio_tone/mk_embed_flash.py. It only supports the `AUDIO_STREAM_READER` type.

##### Application Example

- player/pipeline_embed_flash_tone

##### Header File

- audio_stream/include/embed_flash_stream.h

##### Functions

audio_element_handle_t `embed_flash_stream_init`(embed_flash_stream_cfg_t *config)

  Create an Audio Element handle to stream data from flash to another Element, only support AUDIO_STREAM_READER type.

  Return

    The Audio Element handle

  Parameters

    - `config`: The configuration

esp_err_t `embed_flash_stream_set_context`(audio_element_handle_t embed_stream, const embed_item_info_t *context, int max_num)

  Set the embed flash context.

              This function mainly provides information about embed flash data

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] embed_stream`: The embed flash element handle

    - `[in] context`: The embed flash context

    - `[in] max_num`: The number of embed flash context

##### Structures

struct `embed_flash_stream_cfg_t`

  Flash-embedding stream configurations, if any entry is zero then the configuration will be set to default values.

  Public Members

  int `buf_sz`

    Audio Element Buffer size

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `extern_stack`

    At present, task stack can only be placed on `SRAM`, so it should always be set to `false`

struct `embed_item_info`

  Embed tone information in flash.

  Public Members

  const uint8_t *`address`

    The corresponding address in flash

  int `size`

    Size of corresponding data

##### Macros

`EMBED_FLASH_STREAM_BUF_SIZE`

`EMBED_FLASH_STREAM_TASK_STACK`

`EMBED_FLASH_STREAM_TASK_CORE`

`EMBED_FLASH_STREAM_TASK_PRIO`

`EMBED_FLASH_STREAM_RINGBUFFER_SIZE`

`EMBED_FLASH_STREAM_EXT_STACK`

`EMBED_FLASH_STREAM_CFG_DEFAULT`()

##### Type Definitions

typedef struct embed_item_info `embed_item_info_t`

  Embed tone information in flash.

#### TTS Stream

The tex-to-speech stream (TTS stream) obtains the `esp_tts_voice` data of esp-sr. It only supports the `AUDIO_STREAM_READER` type.

##### Application Example

- Reader example: player/pipeline_tts_stream

##### Header File

- audio_stream/include/tts_stream.h

##### Functions

audio_element_handle_t `tts_stream_init`(tts_stream_cfg_t *config)

  Create a handle to an Audio Element to stream data from TTS to another Element, the stream type only support AUDIO_STREAM_READER for now.

  Return

    The Audio Element handle

  Parameters

    - `config`: The configuration

esp_err_t `tts_stream_set_strings`(audio_element_handle_t el, const char *strings)

  Set tts stream strings.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The audio element handle

    - `[in] strings`: The string pointer

esp_err_t `tts_stream_set_speed`(audio_element_handle_t el, tts_voice_speed_t speed)

  Setting tts stream voice speed.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The esp_audio instance

    - `[in] speed`: Speed will be set. 0-5 is legal. 0 is the slowest speed.

esp_err_t `tts_stream_get_speed`(audio_element_handle_t el, tts_voice_speed_t *speed)

  Get tts stream voice speed.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] el`: The esp_audio instance

    - `[in] speed`: Return tts stream Speed will be [0,5]

##### Structures

struct `tts_stream_cfg_t`

  TTS Stream configurations, if any entry is zero then the configuration will be set to default values.

  Public Members

  audio_stream_type_t `type`

    Stream type

  int `buf_sz`

    Audio Element Buffer size

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `ext_stack`

    Allocate stack on extern ram

##### Macros

`TTS_STREAM_BUF_SIZE`

`TTS_STREAM_TASK_STACK`

`TTS_STREAM_TASK_CORE`

`TTS_STREAM_TASK_PRIO`

`TTS_STREAM_RINGBUFFER_SIZE`

`TTS_STREAM_CFG_DEFAULT`()

##### Enumerations

enum `tts_voice_speed_t`

  Values:

  `TTS_VOICE_SPEED_0`
  `TTS_VOICE_SPEED_1`
  `TTS_VOICE_SPEED_2`
  `TTS_VOICE_SPEED_3`
  `TTS_VOICE_SPEED_4`
  `TTS_VOICE_SPEED_5`
  `TTS_VOICE_SPEED_MAX`

### Playlist

[中文]

A playlist is a list of audio files that can be played back either sequentially or in a specified order.

The `sdcard_scan()` function in the playlist/include/sdcard_scan.h scans the audio files in a microSD card and generate a playlist of files. You can specify file depth and filter out file types when scanning. The playlist instances can be saved to a variety of storage media. The following are the supported storage media:

- Saving to MicroSD Card

- Saving to DRAM

- Saving to NVS Partition in Flash

- Saving to DATA_UNDEFINED Partition in Flash

After scanning the audio files, you can use the `playlist_operator_handle_t` handle to call the corresponding functions to create, save, print playlists, and obtain the path corresponding to the audio ID. Currently, most of the storage media mentioned in this document support the above functions.

See the description below for the API details.

#### Scanning MicroSD Card

The `sdcard_scan()` function can scan audio files in a specified path and generate playlists. It supports the scanning of files at a specified depth and filtering of file types. Then, the playlist can be saved to the specified storage medium using a callback function.

##### Application Example

- player/pipeline_sdcard_mp3_control

- cli

##### Header File

- playlist/include/sdcard_scan.h

##### Functions

esp_err_t `sdcard_scan`(sdcard_scan_cb_t cb, const char *path, int depth, const char *file_extension[], int filter_num, void *user_data)

  Scan files in SD card and use callback function to save files that meet filtering conditions.

  Note

    example sdcard_scan(callback, “/sdcard”, 5, const char *[]{“mp3”, “aac”}, 2, user_data); Scan 5 levels folder in sdcard and save mp3 files and aac files.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `cb`: The callback function

    - `path`: The path to be scanned

    - `depth`: The depth of file scanning // .e.g. if you only want to save files in “/test” , depth = 0. // if you want to save files in “/test/scan_test/”, depth = 1

    - `file_extension`: File extension of files that are supposed to be saved // .e.g. const char *[]{“mp3”, “aac”}

    - `filter_num`: Number of filters

    - `user_data`: The data to be used by callback function

##### Type Definitions

typedef void (*`sdcard_scan_cb_t`)(void *user_data, char *url)

#### Saving Playlist

##### Saving to MicroSD Card

The playlist can be stored in the microSD card. Functions, such as those to save and display the playlist, can be called through the `playlist_operator_handle_t` handle.

###### Application Example

- player/pipeline_sdcard_mp3_control

- cli

##### Header File

- playlist/include/sdcard_list.h

##### Functions

esp_err_t `sdcard_list_create`(playlist_operator_handle_t *handle)

  Create a playlist in sdcard by list id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `[out] handle`: The playlist handle from application layer

esp_err_t `sdcard_list_show`(playlist_operator_handle_t handle)

  Show all the URLs in sdcard playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `sdcard_list_next`(playlist_operator_handle_t handle, int step, char **url_buff)

  The following URLs in sdcard playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `sdcard_list_prev`(playlist_operator_handle_t handle, int step, char **url_buff)

  The previous URLs in sdcard playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

bool `sdcard_list_exist`(playlist_operator_handle_t handle, const char *url)

  Judge whether the url exists in sdcard playlist.

  Return

    - true existence

    - false Non-existent

  Parameters

    - `handle`: Playlist handle

    - `url`: The url to be checked

esp_err_t `sdcard_list_reset`(playlist_operator_handle_t handle)

  Reset sdcard playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `sdcard_list_current`(playlist_operator_handle_t handle, char **url_buff)

  Get current URL in sdcard playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `sdcard_list_choose`(playlist_operator_handle_t handle, int url_id, char **url_buff)

  Choose a url by url id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url_id`: The id of url in sdcard list

    - `[out] url_buff`: A second rank pointer to get a address of URL

int `sdcard_list_get_url_num`(playlist_operator_handle_t handle)

  Get URLs number in sdcard playlist.

  Return

    - URLs number in sdcard playlist

    - ESP_FAIL Fail to get number of urls

  Parameters

    - `handle`: Playlist handle

int `sdcard_list_get_url_id`(playlist_operator_handle_t handle)

  Get current url id in the sdcard playlist.

  Return

    - Current url id in partition playlist

    - ESP_FAIL Fail to get url id

  Parameters

    - `handle`: Playlist handle

esp_err_t `sdcard_list_destroy`(playlist_operator_handle_t handle)

  Destroy sdcard playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `sdcard_list_save`(playlist_operator_handle_t handle, const char *url)

  Save URL to sdcard playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url`: URL to be saved

##### Saving to DRAM

The playlist can be stored in DRAM. Functions, such as those to save and display the playlist, can be called through the `playlist_operator_handle_t` handle.

##### Header File

- playlist/include/dram_list.h

##### Functions

esp_err_t `dram_list_create`(playlist_operator_handle_t *handle)

  Create a playlist in dram.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `[out] handle`: The playlist handle from application layer

esp_err_t `dram_list_save`(playlist_operator_handle_t handle, const char *url)

  Save URL to dram playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url`: URL to be saved

esp_err_t `dram_list_next`(playlist_operator_handle_t handle, int step, char **url_buff)

  The following URLs in dram playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `dram_list_prev`(playlist_operator_handle_t handle, int step, char **url_buff)

  The previous URLs in dram playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

bool `dram_list_exist`(playlist_operator_handle_t handle, const char *url)

  Judge whether the url exists in dram playlist.

  Return

    - true existence

    - false Non-existent

  Parameters

    - `handle`: Playlist handle

    - `url`: The url to be checked

esp_err_t `dram_list_reset`(playlist_operator_handle_t handle)

  Reset dram playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `dram_list_current`(playlist_operator_handle_t handle, char **url_buff)

  The current URL in current playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `dram_list_choose`(playlist_operator_handle_t handle, int url_id, char **url_buff)

  Choose a url by url id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url_id`: The id of url in dram list

    - `[out] url_buff`: A second rank pointer to get a address of URL

int `dram_list_get_url_num`(playlist_operator_handle_t handle)

  Get URLs number in the dram playlist.

  Return

    - URLs number in dram playlist

    - ESP_FAIL Fail to get number of urls

  Parameters

    - `handle`: Playlist handle

int `dram_list_get_url_id`(playlist_operator_handle_t handle)

  Get current url id in the dram playlist.

  Return

    - Current url id in dram playlist

    - ESP_FAIL Fail to get url id

  Parameters

    - `handle`: Playlist handle

esp_err_t `dram_list_show`(playlist_operator_handle_t handle)

  Show all the URLs in the dram playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `dram_list_remove_by_url`(playlist_operator_handle_t handle, const char *url)

  Remove corrsponding url in dram list.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url`: The url to be removed

esp_err_t `dram_list_remove_by_url_id`(playlist_operator_handle_t handle, uint16_t url_id)

  Remove url by id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url_id`: The url id to be removed

esp_err_t `dram_list_destroy`(playlist_operator_handle_t handle)

  Destroy the dram playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

##### Saving to NVS Partition in Flash

The playlist can be stored in the NVS partition in flash. Functions, such as those to save and display the playlist, can be called through the `playlist_operator_handle_t` handle.

##### Header File

- playlist/include/flash_list.h

##### Functions

esp_err_t `flash_list_create`(playlist_operator_handle_t *handle)

  Create a playlist in nvs flash.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `[out] handle`: Playlist handle

esp_err_t `flash_list_save`(playlist_operator_handle_t handle, const char *url)

  Save URL to nvs flash list.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url`: URL to be saved

esp_err_t `flash_list_show`(playlist_operator_handle_t handle)

  Show all the URLs in nvs flash list.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `flash_list_next`(playlist_operator_handle_t handle, int step, char **url_buff)

  The following URLs in nvs flash playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `flash_list_prev`(playlist_operator_handle_t handle, int step, char **url_buff)

  The previous URLs in nvs flash playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `flash_list_current`(playlist_operator_handle_t handle, char **url_buff)

  The current URL in nvs flash playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `[out] url_buff`: A second rank pointer to get a address of URL

bool `flash_list_exist`(playlist_operator_handle_t handle, const char *url)

  Judge whether the url exists in flash playlist.

  Return

    - true existence

    - false Non-existent

  Parameters

    - `handle`: Playlist handle

    - `url`: The url to be checked

esp_err_t `flash_list_reset`(playlist_operator_handle_t handle)

  Reset flash playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `flash_list_choose`(playlist_operator_handle_t handle, int url_id, char **url_buff)

  Choose a url by url id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url_id`: The id of url in flash list

    - `[out] url_buff`: A second rank pointer to get a address of URL

int `flash_list_get_url_num`(playlist_operator_handle_t handle)

  Get URLs number in the flash playlist.

  Return

    - URLs number in flash playlist

    - ESP_FAIL Fail to get number of urls

  Parameters

    - `handle`: Playlist handle

int `flash_list_get_url_id`(playlist_operator_handle_t handle)

  Get current url id in the flash playlist.

  Return

    - Curernt url id in flash playlist

    - ESP_FAIL Fail to get url id

  Parameters

    - `handle`: Playlist handle

esp_err_t `flash_list_destroy`(playlist_operator_handle_t handle)

  Destroy the nvs flash playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

##### Saving to `DATA_UNDEFINED` Partition in Flash

The playlist can be stored in the `DATA_UNDEFINED` partition (see Partition Tables for details) in flash. Functions, such as those to save and display the playlist, can be called through the `playlist_operator_handle_t` handle. Please add the two partitions whose subtypes are 0x06 and 0x07 to the flash partition table first.

##### Header File

- playlist/include/partition_list.h

##### Functions

esp_err_t `partition_list_create`(playlist_operator_handle_t *handle)

  Create a playlist in flash partition by list id.

  Note

    Please add 2 partitions to partition table whose subtype are 0x06 and 0x07 first

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `[out] handle`: The playlist handle from application layer

esp_err_t `partition_list_save`(playlist_operator_handle_t handle, const char *url)

  Save URL to partition playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url`: URL to be saved

esp_err_t `partition_list_next`(playlist_operator_handle_t handle, int step, char **url_buff)

  The following URLs in partition playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `partition_list_prev`(playlist_operator_handle_t handle, int step, char **url_buff)

  The previous URLs in partition playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: The offset of URL from current URL

    - `[out] url_buff`: A second rank pointer to get a address of URL

bool `partition_list_exist`(playlist_operator_handle_t handle, const char *url)

  Judge whether the url exists in partition playlist.

  Return

    - true existence

    - false Non-existent

  Parameters

    - `handle`: Playlist handle

    - `url`: The url to be checked

esp_err_t `partition_list_reset`(playlist_operator_handle_t handle)

  Reset partition playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `partition_list_current`(playlist_operator_handle_t handle, char **url_buff)

  Get current URL in the partition playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `partition_list_choose`(playlist_operator_handle_t handle, int url_id, char **url_buff)

  Choose a url by url id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url_id`: The id of url in partition list

    - `[out] url_buff`: A second rank pointer to get a address of URL

int `partition_list_get_url_num`(playlist_operator_handle_t handle)

  Get URLs number in the partition playlist.

  Return

    - URLs number in partition playlist

    - ESP_FAIL Fail to get number of urls

  Parameters

    - `handle`: Playlist handle

int `partition_list_get_url_id`(playlist_operator_handle_t handle)

  Get curernt url id in the partition playlist.

  Return

    - Current url id in partition playlist

    - ESP_FAIL Fail to get url id

  Parameters

    - `handle`: Playlist handle

esp_err_t `partition_list_show`(playlist_operator_handle_t handle)

  Show all the URLs in the partition playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `partition_list_destroy`(playlist_operator_handle_t handle)

  Destroy the partition playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

#### Playlist Manager

Playlist Manager manages the above playlists and can add multiple playlist instances to the `playlist_handle_t` handle.

##### Header File

- playlist/include/playlist.h

##### Functions

playlist_handle_t `playlist_create`(void)

  Create a playlist manager handle.

  Return

    - playlist handle success

    - NULL failed

esp_err_t `playlist_add`(playlist_handle_t handle, playlist_operator_handle_t list_handle, uint8_t list_id)

  Create a playlist manager and add playlist handle to it.

  Note

    The partition playlist can only be added once, or it will be overwrited by the newest partiiton playlist

  Note

    Different lists must use different IDs, because even if they are in different handles, list_id is the only indicator that distinguishes them.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist manager handle

    - `list_handle`: The playlist handle to be added

    - `list_id`: The playlist id to be registered

esp_err_t `playlist_checkout_by_id`(playlist_handle_t handle, uint8_t id)

  Playlist checkout by list id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `id`: Specified list id

int `playlist_get_list_num`(playlist_handle_t handle)

  Get number of playlists in the handle.

  Return

    - success Number of playlists in handle

    - failed -1

  Parameters

    - `handle`: Playlist handle

playlist_type_t `playlist_get_current_list_type`(playlist_handle_t handle)

  Get current playlist type.

  Return

    - success Type of current playlist

    - failed -1

  Parameters

    - `handle`: Playlist handle

int `playlist_get_current_list_id`(playlist_handle_t handle)

  Get current playlist id.

  Return

    - success Current playlist id

    - failed -1

  Parameters

    - `handle`: Playlist handle

esp_err_t `playlist_get_current_list_url`(playlist_handle_t handle, char **url_buff)

  Get current URL in current playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `[out] url_buff`: A second rank pointer to get a address of URL

int `playlist_get_current_list_url_num`(playlist_handle_t handle)

  Get number of URLs in current playlist.

  Return

    Number of URLS in current playlsit

  Parameters

    - `handle`: Playlist handle

int `playlist_get_current_list_url_id`(playlist_handle_t handle)

  Get current url id in current playlist.

  Return

    Current url’s id in current playlsit

  Parameters

    - `handle`: Playlist handle

esp_err_t `playlist_save`(playlist_handle_t handle, const char *url)

  Save a URL to the current playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url`: The URL to be saved ot sdcard

esp_err_t `playlist_next`(playlist_handle_t handle, int step, char **url_buff)

  Next URl in current playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: Next steps from current position

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `playlist_prev`(playlist_handle_t handle, int step, char **url_buff)

  Previous URL in current playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `step`: Previous steps from current position

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `playlist_choose`(playlist_handle_t handle, int url_id, char **url_buff)

  Choose a url by url id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url_id`: The id of url in current list

    - `[out] url_buff`: A second rank pointer to get a address of URL

esp_err_t `playlist_show`(playlist_handle_t handle)

  Show URLs in current playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `playlist_reset`(playlist_handle_t handle)

  Reset current playlist.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

esp_err_t `playlist_remove_by_url`(playlist_handle_t handle, const char *url)

  Remove corresponding url.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url`: The url to be removed

esp_err_t `playlist_remove_by_url_id`(playlist_handle_t handle, uint16_t url_id)

  Remove url by url id.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

    - `url_id`: The id of url to be removed

bool `playlist_exist`(playlist_handle_t handle, const char *url)

  Judge whether the url exists in current playlist.

  Return

    - true existence

    - false Non-existent

  Parameters

    - `handle`: Playlist handle

    - `url`: The url to be checked

esp_err_t `playlist_destroy`(playlist_handle_t handle)

  Destroy all playlists in the handle.

  Return

    - ESP_OK success

    - ESP_FAIL failed

  Parameters

    - `handle`: Playlist handle

##### Structures

struct `playlist_operation_t`

  All types of Playlists’ operation.

  Public Members

  esp_err_t (*`show`)(void *playlist)

    Show all the URLs in playlist

  esp_err_t (*`save`)(void *playlist, const char *url)

    Save URLs to playlist

  esp_err_t (*`next`)(void *playlist, int step, char **url_buff)

    Get next URL in playlist

  esp_err_t (*`prev`)(void *playlist, int step, char **url_buff)

    Get previous URL in playlist

  esp_err_t (*`reset`)(void *playlist)

    Reset the playlist

  esp_err_t (*`choose`)(void *playlist, int url_id, char **url_buff)

    Get url by url id

  esp_err_t (*`current`)(void *playlist, char **url_buff)

    Get current URL in playlist

  esp_err_t (*`destroy`)(void *playlist)

    Destroy playlist

  bool (*`exist`)(void *playlist, const char *url)

    Judge whether the url exists

  int (*`get_url_num`)(void *playlist)

    Get number of URLS in current playlist

  int (*`get_url_id`)(void *playlist)

    Get current url id in playlist

  playlist_type_t `type`

    Type of playlist

  esp_err_t (*`remove_by_url`)(void *playlist, const char *url)

    Remove the corresponding url

  esp_err_t (*`remove_by_id`)(void *playlist, uint16_t url_id)

    Remove url by id

struct `playlist_operator_t`

  Information of playlist manager node.

  Public Members

  void *`playlist`

    Specific playlist’s pointer

  esp_err_t (*`get_operation`)(playlist_operation_t *operation)

    Function pointer to get playlists’ handle

##### Type Definitions

typedef playlist_operator_t *`playlist_operator_handle_t`

typedef struct playlist_handle *`playlist_handle_t`

##### Enumerations

enum `playlist_type_t`

  Type of playlist.

  Values:

  `PLAYLIST_UNKNOWN` = -1

    Unknown type

  `PLAYLIST_SDCARD`

    Playlist in sdcard

  `PLAYLIST_FLASH`

    Playlist in nvs

  `PLAYLIST_DRAM`

    Playlist in ram

  `PLAYLIST_PARTITION`

    Playlist in partition

### Codecs

#### AAC Decoder

Decode an audio data stream provided in AAC format.

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/aac_decoder.h

###### Functions

audio_element_handle_t `aac_decoder_init`(aac_decoder_cfg_t *config)

  Create an Audio Element handle to decode incoming AAC data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `aac_decoder_cfg_t`

  AAC Decoder configuration.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    CPU core number (0 or 1) where decoder task in running

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

  bool `plus_enable`

    Dynamically enable HE-AAC (v1 v2) decoding

###### Macros

`AAC_DECODER_TASK_STACK_SIZE`

`AAC_DECODER_TASK_CORE`

`AAC_DECODER_TASK_PRIO`

`AAC_DECODER_RINGBUFFER_SIZE`

`DEFAULT_AAC_DECODER_CONFIG`()

#### AMR Decoder and Encoder

Decode and encode an audio data stream from / to AMR format. Encoders cover both AMR-NB and AMR-WB formats.

##### Application Examples

Implementation of this API is demonstrated in the following examples:

- player/pipeline_play_sdcard_music

- recorder/pipeline_wav_amr_sdcard

##### API Reference - Decoder

###### Header File

- esp-adf-libs/esp_codec/include/codec/amr_decoder.h

###### Functions

audio_element_handle_t `amr_decoder_init`(amr_decoder_cfg_t *config)

  Create an Audio Element handle to decode incoming AMR data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `amr_decoder_cfg_t`

  AMR Decoder configuration.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    CPU core number (0 or 1) where decoder task in running

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`AMR_DECODER_TASK_STACK_SIZE`

`AMR_DECODER_TASK_CORE`

`AMR_DECODER_TASK_PRIO`

`AMR_DECODER_RINGBUFFER_SIZE`

`DEFAULT_AMR_DECODER_CONFIG`()

##### API Reference - AMR-NB Encoder

###### Header File

- esp-adf-libs/esp_codec/include/codec/amrnb_encoder.h

###### Functions

esp_err_t `amrnb_encoder_set_bitrate`(audio_element_handle_t self, amrnb_encoder_bitrate_t bitrate_mode)

  Set AMRNB encoder bitrate.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `self`: Audio element handle

    - `bitrate_mode`: Bitrate choose, value from amrnb_encoder_bitrate_t

audio_element_handle_t `amrnb_encoder_init`(amrnb_encoder_cfg_t *config)

  Create an Audio Element handle to encode incoming AMRNB data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `amrnb_encoder_cfg_t`

  AMRNB Encoder configurations.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  amrnb_encoder_bitrate_t `bitrate_mode`

    AMRNB Encoder bitrate choose

  bool `contain_amrnb_header`

    Choose to contain amrnb header in amrnb encoder whether or not (true or false, true means choose to contain amrnb header)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`AMRNB_ENCODER_TASK_STACK`

`AMRNB_ENCODER_TASK_CORE`

`AMRNB_ENCODER_TASK_PRIO`

`AMRNB_ENCODER_RINGBUFFER_SIZE`

`DEFAULT_AMRNB_ENCODER_CONFIG`()

###### Enumerations

enum `amrnb_encoder_bitrate_t`

  Enum of AMRNB Encoder bitrate choose.

  Values:

  `AMRNB_ENC_BITRATE_UNKNOW` = -1

    Invalid mode

  `AMRNB_ENC_BITRATE_MR475` = 0
  `AMRNB_ENC_BITRATE_MR515` = 1
  `AMRNB_ENC_BITRATE_MR59` = 2
  `AMRNB_ENC_BITRATE_MR67` = 3
  `AMRNB_ENC_BITRATE_MR74` = 4
  `AMRNB_ENC_BITRATE_MR795` = 5
  `AMRNB_ENC_BITRATE_MR102` = 6
  `AMRNB_ENC_BITRATE_MR122` = 7
  `AMRNB_ENC_BITRATE_MRDTX` = 8
  `AMRNB_ENC_BITRATE_N_MODES` = 9

##### API Reference - AMR-WB Encoder

###### Header File

- esp-adf-libs/esp_codec/include/codec/amrwb_encoder.h

###### Functions

esp_err_t `amrwb_encoder_set_bitrate`(audio_element_handle_t self, amrwb_encoder_bitrate_t bitrate_mode)

  Set AMRWB encoder bitrate.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `self`: Audio element handle

    - `bitrate_mode`: Bitrate choose, value from amrwb_encoder_bitrate_t

audio_element_handle_t `amrwb_encoder_init`(amrwb_encoder_cfg_t *config)

  Create an Audio Element handle to encode incoming amrwb data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `amrwb_encoder_cfg_t`

  AMRWB Encoder configurations.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  amrwb_encoder_bitrate_t `bitrate_mode`

    AMRWB Encoder bitrate choose

  bool `contain_amrwb_header`

    Choose to contain amrwb header in amrwb encoder whether or not (true or false, true means choose to contain amrwb header)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`AMRWB_ENCODER_TASK_STACK`

`AMRWB_ENCODER_TASK_CORE`

`AMRWB_ENCODER_TASK_PRIO`

`AMRWB_ENCODER_RINGBUFFER_SIZE`

`DEFAULT_AMRWB_ENCODER_CONFIG`()

###### Enumerations

enum `amrwb_encoder_bitrate_t`

  Enum of AMRWB Encoder bitrate choose.

  Values:

  `AMRWB_ENC_BITRATE_MDNONE` = -1

    Invalid mode

  `AMRWB_ENC_BITRATE_MD66` = 0

    6.60kbps

  `AMRWB_ENC_BITRATE_MD885` = 1

    8.85kbps

  `AMRWB_ENC_BITRATE_MD1265` = 2

    12.65kbps

  `AMRWB_ENC_BITRATE_MD1425` = 3

    14.25kbps

  `AMRWB_ENC_BITRATE_MD1585` = 4

    15.85bps

  `AMRWB_ENC_BITRATE_MD1825` = 5

    18.25bps

  `AMRWB_ENC_BITRATE_MD1985` = 6

    19.85kbps

  `AMRWB_ENC_BITRATE_MD2305` = 7

    23.05kbps

  `AMRWB_ENC_BITRATE_MD2385` = 8

    23.85kbps>

  `AMRWB_ENC_BITRATE_N_MODES` = 9

    Invalid mode

#### FLAC Decoder

Decode an audio data stream provided in FLAC format.

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/flac_decoder.h

###### Functions

audio_element_handle_t `flac_decoder_init`(flac_decoder_cfg_t *config)

  Create an Audio Element handle to decode incoming FLAC data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `flac_decoder_cfg_t`

  FLAC Decoder configuration.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    CPU core number (0 or 1) where decoder task in running

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`FLAC_DECODER_TASK_STACK_SIZE`

`FLAC_DECODER_TASK_CORE`

`FLAC_DECODER_TASK_PRIO`

`FLAC_DECODER_RINGBUFFER_SIZE`

`DEFAULT_FLAC_DECODER_CONFIG`()

#### MP3 Decoder

Decode an audio data stream provided in MP3 format.

##### Application Examples

Implementation of this API is demonstrated in the following examples:

- get-started/play_mp3_control

- player/pipeline_play_sdcard_music

- player/pipeline_play_mp3_with_dac_or_pwm

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/mp3_decoder.h

###### Functions

audio_element_handle_t `mp3_decoder_init`(mp3_decoder_cfg_t *config)

  Create an Audio Element handle to decode incoming MP3 data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

const esp_id3_info_t *`mp3_decoder_get_id3_info`(audio_element_handle_t self)

  Get ID3 information.

  Return

    esp_id3_info_t: success NULL: ID3 is not exist or memory aloocation failed.

  Parameters

    - `self`: The audio element handle

###### Structures

struct `mp3_decoder_cfg_t`

  Mp3 Decoder configuration.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    CPU core number (0 or 1) where decoder task in running

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

  bool `id3_parse_enable`

    True: parse ID3. False: Don’t parse ID3

###### Macros

`MP3_DECODER_TASK_STACK_SIZE`

`MP3_DECODER_TASK_CORE`

`MP3_DECODER_TASK_PRIO`

`MP3_DECODER_RINGBUFFER_SIZE`

`DEFAULT_MP3_DECODER_CONFIG`()

#### OGG Decoder

Decode an audio data stream provided in OGG format.

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/ogg_decoder.h

###### Functions

audio_element_handle_t `ogg_decoder_init`(ogg_decoder_cfg_t *config)

  Create an Audio Element handle to decode incoming OGG data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `ogg_decoder_cfg_t`

  OGG Decoder configuration.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    CPU core number (0 or 1) where decoder task in running

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`OGG_DECODER_TASK_STACK_SIZE`

`OGG_DECODER_TASK_CORE`

`OGG_DECODER_TASK_PRIO`

`OGG_DECODER_RINGBUFFER_SIZE`

`DEFAULT_OGG_DECODER_CONFIG`()

#### OPUS Decoder

Decode an audio data stream provided in OPUS format.

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/opus_decoder.h

###### Functions

audio_element_handle_t `decoder_opus_init`(opus_decoder_cfg_t *config)

  Create an Audio Element handle to decode incoming OPUS data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `opus_decoder_cfg_t`

  OPUS Decoder configuration.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    CPU core number (0 or 1) where decoder task in running

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`OPUS_DECODER_TASK_STACK_SIZE`

`OPUS_DECODER_TASK_CORE`

`OPUS_DECODER_TASK_PRIO`

`OPUS_DECODER_RINGBUFFER_SIZE`

`DEFAULT_OPUS_DECODER_CONFIG`()

#### WAV Decoder and Encoder

Decode and encode an audio data stream from / to WAV format.

##### Application Examples

Implementation of this API is demonstrated in the following examples:

- player/pipeline_play_sdcard_music

- recorder/pipeline_wav_amr_sdcard

##### API Reference - Decoder

###### Header File

- esp-adf-libs/esp_codec/include/codec/wav_decoder.h

###### Functions

audio_element_handle_t `wav_decoder_init`(wav_decoder_cfg_t *config)

  Create an Audio Element handle to decode incoming WAV data.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `wav_decoder_cfg_t`

  brief WAV Decoder configurations

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`WAV_DECODER_TASK_STACK`

`WAV_DECODER_TASK_CORE`

`WAV_DECODER_TASK_PRIO`

`WAV_DECODER_RINGBUFFER_SIZE`

`DEFAULT_WAV_DECODER_CONFIG`()

##### API Reference - Encoder

###### Header File

- esp-adf-libs/esp_codec/include/codec/wav_encoder.h

###### Functions

audio_element_handle_t `wav_encoder_init`(wav_encoder_cfg_t *config)

  Create a handle to an Audio Element to encode incoming data using WAV format.

  Return

    The audio element handle

  Parameters

    - `config`: The configuration

###### Structures

struct `wav_encoder_cfg_t`

  WAV Encoder configurations.

  Public Members

  int `out_rb_size`

    Size of output ringbuffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core (0 or 1)

  int `task_prio`

    Task priority (based on freeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`WAV_ENCODER_TASK_STACK`

`WAV_ENCODER_TASK_CORE`

`WAV_ENCODER_TASK_PRIO`

`WAV_ENCODER_RINGBUFFER_SIZE`

`DEFAULT_WAV_ENCODER_CONFIG`()

### Audio Processing

There are couple of options implemented in the ESP-ADF to modify contents of an audio stream:

- Combine contents of two audio streams using Downmix

- Apply ten band Equalizer

- Change audio sampling frequency and convert between single and two channel with Resample Filter

- Modify pitch and speed of the stream using Sonic

Please refer to description of respective APIs below.

#### Downmix

This API is intended for mixing of two audio files (streams), defined as the base audio file and the newcome audio file, into one output audio file.

The newcome audio file will be downmixed into the base audio file with individual gains applied to each file.

Illustration of Downmixing Process

The number of channel(s) of the output audio file will be the same with that of the base audio file. The number of channel(s) of the newcome audio file will also be changed to the same with the base audio file, if it is different from that of the base audio file.

The downmix process has 3 states:

> - Bypass Downmixing – Only the base audio file will be processed;

> - Switch on Downmixing – The base audio file and the target audio file will first enter the transition period, during which the gains of these two files will be changed from the original level to the target level; then enter the stable period, sharing a same target gain;

> - Switch off Downmixing – The base audio file and the target audio file will first enter the transition period, during which the gains of these two files will be changed back to their original levels; then enter the stable period, with their original gains, respectively. After that, the downmix process enters the bypass state.

Note that, the sample rates of the base audio file and the newcome audio file must be the same, otherwise an error occurs.

##### Application Example

Implementation of this API is demonstrated in advanced_examples/downmix_pipeline example.

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/downmix.h

###### Functions

void `downmix_set_input_rb_timeout`(audio_element_handle_t self, int ticks_to_wait, int index)

  Sets the downmix timeout.

  Parameters

    - `self`: Audio element handle

    - `ticks_to_wait`: Input ringbuffer timeout

    - `index`: The index of multi input ringbuffer

void `downmix_set_input_rb`(audio_element_handle_t self, ringbuf_handle_t rb, int index)

  Sets the downmix input ringbuffer. refer to `ringbuf.h`

  Parameters

    - `self`: Audio element handle

    - `rb`: Handle of ringbuffer

    - `index`: The index of multi input ringbuffer.

esp_err_t `downmix_set_output_type`(audio_element_handle_t self, esp_downmix_output_type_t output_type)

  Set channel mode of output data. Only supported mono and dual.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `output_type`: Down-mixer output type.

esp_err_t `downmix_set_work_mode`(audio_element_handle_t self, esp_downmix_work_mode_t mode)

  Sets BYPASS, ON or OFF status of down-mixer.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `mode`: Down-mixer work mode.

esp_err_t `downmix_set_out_ctx_info`(audio_element_handle_t self, esp_downmix_out_ctx_type_t out_ctx)

  Passes content of per channel output stream by down-mixer.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `out_ctx`: Content of output stream.

esp_err_t `downmix_set_source_stream_info`(audio_element_handle_t self, int rate, int ch, int index)

  Sets the sample rate and the number of channels of input stream to be processed.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `rate`: Sample rate of the input stream

    - `ch`: Channel number of the input stream. Only supported mono and dual.

    - `index`: The index of input stream. The index must be in [0, SOURCE_NUM_MAX - 1] range.

esp_err_t `downmix_set_gain_info`(audio_element_handle_t self, float *gain, int index)

  Sets the audio gain to be processed.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `gain`: The gain array of downmix which the array size is 2 and the gain data range is [-100, 100], unit: dB.

    - `index`: The index of input stream. The index must be in [0, SOURCE_NUM_MAX - 1] range.

esp_err_t `downmix_set_transit_time_info`(audio_element_handle_t self, int transit_time, int index)

  Sets the audio `transit_time` to be processed.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `transit_time`: The reset value of `transit_time`

    - `index`: The index of input stream. The index must be in [0, SOURCE_NUM_MAX - 1] range

esp_err_t `source_info_init`(audio_element_handle_t self, esp_downmix_input_info_t *source_info)

  Initializes information of the source streams for downmixing.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `source_info`: The information array of source streams

audio_element_handle_t `downmix_init`(downmix_cfg_t *config)

  Initializes the Audio Element handle for downmixing.

  Return

    The audio element handler

  Parameters

    - `config`: the configuration

###### Structures

struct `downmix_cfg_t`

  Downmix configuration.

  Public Members

  esp_downmix_info_t `downmix_info`

    Downmix information

  int `max_sample`

    The number of samples per downmix processing

  int `out_rb_size`

    Size of ring buffer

  int `task_stack`

    Size of task stack

  int `task_core`

    Task running in core…

  int `task_prio`

    Task priority (based on the FreeRTOS priority)

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`DOWNMIX_TASK_STACK`

`DOWNMIX_TASK_CORE`

`DOWNMIX_TASK_PRIO`

`DOWNMIX_RINGBUFFER_SIZE`

`DM_BUF_SIZE`

`DEFAULT_DOWNMIX_CONFIG`()

#### Equalizer

Provided in this API equalizer supports:

- fixed number of ten (10) bands;

- four sample rates: 11025 Hz, 22050 Hz, 44100 Hz and 48000 Hz.

The center frequencies of bands are shown in table below.

Band Index | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Frequency | 31 Hz | 62 Hz | 125 Hz | 250 Hz | 500 Hz | 1 kHz | 2 kHz | 4 kHz | 8 kHz | 16 kHz

Default gain of each band is -13 dB. To set the gains of all bands use structure `equalizer_cfg`. To set the gain of individual band use function `equalizer_set_gain_info()`.

##### Application Example

Implementation of this API is demonstrated in the audio_processing/pipeline_equalizer example.

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/equalizer.h

###### Functions

esp_err_t `equalizer_set_info`(audio_element_handle_t self, int rate, int ch)

  Set the audio sample rate and the number of channels to be processed by the equalizer.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `rate`: Audio sample rate

    - `ch`: Audio channel

esp_err_t `equalizer_set_gain_info`(audio_element_handle_t self, int index, int value_gain, bool is_channels_gain_equal)

  Set the audio gain to be processed by the equalizer.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `index`: The position of center frequencies of equalizer. If channel is mono, the index range is [0, 9]; If channel is stereo and `is_channels_gain_equal` is true, the index range is [0, 9]; If channel is stereo and `is_channels_gain_equal` is false, the index range is [0, 19];

    - `value_gain`: The value of audio gain which in `index`

    - `is_channels_gain_equal`: If audio channel is stereo, the audio gain values of two channels are equal when `is_channels_gain_equal` is `true`, otherwise it means unequal.

audio_element_handle_t `equalizer_init`(equalizer_cfg_t *config)

  Create an Audio Element handle that equalizes incoming data.

  Return

    The audio element handler

  Parameters

    - `config`: The configuration

###### Structures

struct `equalizer_cfg`

  Equalizer Configuration.

  +——————————————————–

  + | MONO | +——————————————————–+ | Only Left channel/Only Right channel | +——————————————————–+ |band0|band1|band2|band3|band4|band5|band6|band7|band8|band9| +——————————————————–+ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | +——————————————————–+
  Note

    1) This figure indicate the default eq gain of every band in current equalizer. 2) Every channel have 10 band to set.

  +——————————————————–+——————————————————–+ | DUAL | +——————————————————–+——————————————————–+ | Left channel | Right channel | +——————————————————–+——————————————————–+ |band0|band1|band2|band3|band4|band5|band6|band7|band8|band9|band0|band1|band2|band3|band4|band5|band6|band7|band8|band9| +——————————————————–+——————————————————–+ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | +——————————————————–+——————————————————–+

  3) Different sample rates support different EQ frequency bands. 11025: {31, 62, 125, 250, 500, 1000, 2000, 3000, 4000, 5500} 22050: {31, 62, 125, 250, 500, 1000, 2000, 4000, 8000, 11000} 44100/48000: {31, 62, 125, 250, 500, 1000, 2000, 4000, 8000, 16000}

  Public Members

  int `samplerate`

    Audio sample rate. Supported samplerate: 11025, 22050, 44100, 48000, unit: Hz

  int `channel`

    Number of audio channels. Supported channel: mono, stereo

  int *`set_gain`

    Equalizer gain

  int `out_rb_size`

    Size of output ring buffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core…

  int `task_prio`

    Task priority

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`EQUALIZER_TASK_STACK`

`EQUALIZER_TASK_CORE`

`EQUALIZER_TASK_PRIO`

`EQUALIZER_RINGBUFFER_SIZE`

`DEFAULT_EQUALIZER_CONFIG`()

###### Type Definitions

typedef struct equalizer_cfg `equalizer_cfg_t`

  Equalizer Configuration.

  +——————————————————–

  + | MONO | +——————————————————–+ | Only Left channel/Only Right channel | +——————————————————–+ |band0|band1|band2|band3|band4|band5|band6|band7|band8|band9| +——————————————————–+ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | +——————————————————–+
  Note

    1) This figure indicate the default eq gain of every band in current equalizer. 2) Every channel have 10 band to set.

  +——————————————————–+——————————————————–+ | DUAL | +——————————————————–+——————————————————–+ | Left channel | Right channel | +——————————————————–+——————————————————–+ |band0|band1|band2|band3|band4|band5|band6|band7|band8|band9|band0|band1|band2|band3|band4|band5|band6|band7|band8|band9| +——————————————————–+——————————————————–+ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | +——————————————————–+——————————————————–+

  3) Different sample rates support different EQ frequency bands. 11025: {31, 62, 125, 250, 500, 1000, 2000, 3000, 4000, 5500} 22050: {31, 62, 125, 250, 500, 1000, 2000, 4000, 8000, 11000} 44100/48000: {31, 62, 125, 250, 500, 1000, 2000, 4000, 8000, 16000}

#### Resample Filter

The Resample Filter is an Audio Element designed to downsample or upsample the incoming data stream as well as to convert the data between stereo and mono.

##### Application Example

Implementation of this API is demonstrated in the following examples:

- audio_processing/pipeline_resample

- audio_processing/pipeline_spiffs_amr_resample

- get-started/play_mp3_control

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/filter_resample.h

###### Functions

esp_err_t `rsp_filter_set_src_info`(audio_element_handle_t self, int src_rate, int src_ch)

  Set the source audio sample rate and the number of channels to be processed by the resample. If need change bits or not ensure source data infomation, please use rsp_filter_change_src_info to instead this function.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `src_rate`: The sample rate of stream data

    - `src_ch`: The number channels of stream data

esp_err_t `rsp_filter_change_src_info`(audio_element_handle_t self, int src_rate, int src_ch, int src_bit)

  Set the source audio sample rate, the number of channels and bits per sample to be processed by the resample.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `src_rate`: The sample rate of stream data

    - `src_ch`: The number channels of stream data

    - `src_bit`: The bit per sample of stream data

audio_element_handle_t `rsp_filter_init`(rsp_filter_cfg_t *config)

  Create an Audio Element handle to resample incoming data.

          Depending on configuration, there are upsampling, downsampling, as well as
          converting data between mono and dual.

          - If the esp_resample_mode_t is `RESAMPLE_DECODE_MODE`, `src_rate` and `src_ch` will be fetched from `audio_element_getinfo`.
          - If the esp_resample_mode_t is `RESAMPLE_ENCODE_MODE`, `src_rate`, `src_ch`, `dest_rate` and `dest_ch` must be configured.

  Return

    The audio element handler

  Parameters

    - `config`: The configuration

###### Structures

struct `rsp_filter_cfg_t`

  Resample Filter Configuration.

  Public Members

  int `src_rate`

    The sampling rate of the source PCM file (in Hz)

  int `src_ch`

    The number of channel(s) of the source PCM file (Mono=1, Dual=2)

  int `dest_rate`

    The sampling rate of the destination PCM file (in Hz)

  int `dest_bits`

    The bit for sample of the destination PCM data. Currently, supported bit width :16 bits.

  int `dest_ch`

    The number of channel(s) of the destination PCM file (Mono=1, Dual=2)

  int `src_bits`

    The bit for sample of the source PCM data. Currently, supported bit width :8bits 16 bits 24bits 32bits.

  esp_resample_mode_t `mode`

    The resampling mode (the encoding mode or the decoding mode). For decoding mode, input PCM length is constant; for encoding mode, output PCM length is constant.

  int `max_indata_bytes`

    The maximum buffer size of the input PCM (in bytes)

  int `out_len_bytes`

    The buffer length of the output stream data. This parameter must be configured in encoding mode.

  esp_resample_type_t `type`

    The resampling type (Automatic, Upsampling and Downsampling)

  int `complexity`

    Indicates the complexity of the resampling. This parameter is only valid when a FIR filter is used. Range:[1, 5]; 1 indicates the lowest complexity, which means the accuracy is the lowest and the speed is the fastest; Meanwhile, 5 indicates the highest complexity, which means the accuracy is the highest and the speed is the slowest.If user set `complexity` less than 1, `complexity` can be set 1. If user set `complexity` more than 5, `complexity` can be set 5.

  int `down_ch_idx`

    Indicates the channel that is selected (the right channel or the left channel). This parameter is only valid when the complexity parameter is set to 0 and the number of channel(s) of the input file has changed from dual to mono.

  esp_rsp_prefer_type_t `prefer_flag`

    The select flag about lesser CPU usage or lower INRAM usage, refer to esp_resample.h

  int `out_rb_size`

    Output ringbuffer size

  int `task_stack`

    Task stack size

  int `task_core`

    Task running on core

  int `task_prio`

    Task priority

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`RSP_FILTER_BUFFER_BYTE`

`RSP_FILTER_TASK_STACK`

`RSP_FILTER_TASK_CORE`

`RSP_FILTER_TASK_PRIO`

`RSP_FILTER_RINGBUFFER_SIZE`

`DEFAULT_RESAMPLE_FILTER_CONFIG`()

#### Sonic

The Sonic component acts as a multidimensional filter that lets you adjust audio parameters of a WAV stream. This functionality may be useful to e.g. increase playback speed of an audio recording by a user selectable rate.

The following parameters can be adjusted:

> - speed

> - pitch

> - interpolation type

The adjustments of the first two parameters are represented by float values that provide the rate of adjustment. For example, to increase the speed of an audio sample by 2 times, call `sonic_set_pitch_and_speed_info(el, 1.0, 2.0)`. To keep the speed as it is, call `sonic_set_pitch_and_speed_info(el, 1.0, 1.0)`.

For the interpolation type you may select either faster but less accurate linear interpolation, or slower but more accurate FIR interpolation.

##### Application Example

Implementation of this API is demonstrated in audio_processing/pipeline_sonic example.

##### API Reference

###### Header File

- esp-adf-libs/esp_codec/include/codec/audio_sonic.h

###### Functions

esp_err_t `sonic_set_info`(audio_element_handle_t self, int rate, int ch)

  Sets the audio sample rate and the number of channels to be processed by the sonic.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `rate`: The sample rate of stream data

    - `ch`: The channel numbers of stream data

esp_err_t `sonic_set_pitch_and_speed_info`(audio_element_handle_t self, float pitch, float speed)

  Sets the audio pitch and speed to be processed by the sonic.

  Return

    - ESP_OK on success

    - ESP_ERR_INVALID_ARG invalid arguments

  Parameters

    - `self`: Audio element handle

    - `pitch`: Scale factor of pitch of audio file. 0 means the original pitch. The range is [0.2 4.0].

    - `speed`: Scale factor of speed of audio file. 0 means the original speed. The range is [0.1 8.0].

audio_element_handle_t `sonic_init`(sonic_cfg_t *config)

  Creates an Audio Element handle for sonic.

  Return

    The audio element handler

  Parameters

    - `config`: The sonic configuration

###### Structures

struct `sonic_info_t`

  Information on audio file and configuration parameters required by sonic to process the file.

  Public Members

  int `samplerate`

    Audio file sample rate (in Hz)

  int `channel`

    Number of audio file channels (Mono=1, Dual=2)

  int `resample_linear_interpolate`

    Flag of using simple linear interpolation. 1 indicates using simple linear interpolation. 0 indicates not using simple linear interpolation.

  float `pitch`

    Scale factor of pitch of audio file. If the value of ‘pitch’ is 0.3, the pitch of audio file processed by sonic islower than the original. If the value of ‘pitch’ is 1.3, the pitch of audio file processed by sonic is 30% higher than the original.

  float `speed`

    Scale factor of speed of audio file. If the value of ‘speed’ is 0.3, the speed of audio file processed by sonic is 70% slower than the original. If the value of ‘speed’ is 1.3, the speed of audio file processed by sonic is 30% faster than the original.

struct `sonic_cfg_t`

  Sonic configuration.

  Public Members

  sonic_info_t `sonic_info`

    Information of sonic

  int `out_rb_size`

    Size of output ring buffer

  int `task_stack`

    Task stack size

  int `task_core`

    Task running in core

  int `task_prio`

    Task priority

  bool `stack_in_ext`

    Try to allocate stack in external memory

###### Macros

`SONIC_SET_VALUE_FOR_INITIALIZATION`

`SONIC_TASK_STACK`

`SONIC_TASK_CORE`

`SONIC_TASK_PRIO`

`SONIC_RINGBUFFER_SIZE`

`DEFAULT_SONIC_CONFIG`()

### Services

[中文]

A service is a software implementation of specific product functions, such as input keys, network configuration management, and battery check. Each service is also an abstraction of hardware. For example, the input key service supports ADC keys and GPIO keys. Services can be reused on different products, and high-level APIs and events allow easy and convenient product development.

For details please refer to descriptions listed below.

#### Bluetooth Service

[中文]

The Bluetooth service is dedicated to interface with Bluetooth devices and provides support for the following protocols:

- HFP (Hands-Free Profile): remotely controlling the mobile phone by the Hands-Free device and the voice connections between them

- A2DP (Advanced Audio Distribution Profile): implementing streaming of multimedia audio using a Bluetooth connection

- AVRCP (Audio Video Remote Control Profile): used together with A2DP for remote control of devices such as headphones, car audio systems, or speakers

##### Application Example

Implementation of this API is demonstrated in the following example:

- player/pipeline_bt_sink

###### Header File

- bluetooth_service/include/bluetooth_service.h

###### Functions

esp_err_t `bluetooth_service_start`(bluetooth_service_cfg_t *config)

  Initialize and start the Bluetooth service. This function can only be called for one time, and `bluetooth_service_destroy` must be called after use.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `config`: The configuration

audio_element_handle_t `bluetooth_service_create_stream`()

  Create Bluetooth stream, it is valid when Bluetooth service has started. The returned audio stream compatible with existing audio streams and can be used with the Audio Pipeline.

  Return

    The Audio Element handle

esp_periph_handle_t `bluetooth_service_create_periph`()

  Create Bluetooth peripheral, it is valid when Bluetooth service has started. The returned bluetooth peripheral compatible with existing peripherals and can be used with the ESP Peripherals.

  Return

    The Peripheral handle

esp_err_t `periph_bluetooth_play`(esp_periph_handle_t periph)

  Send the AVRC passthrough command (PLAY) to the Bluetooth device.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_pause`(esp_periph_handle_t periph)

  Send the AVRC passthrough command (PAUSE) to the Bluetooth device.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_stop`(esp_periph_handle_t periph)

  Send the AVRC passthrough command (STOP) to the Bluetooth device.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_next`(esp_periph_handle_t periph)

  Send the AVRC passthrough command (NEXT) to the Bluetooth device.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_prev`(esp_periph_handle_t periph)

  Send the AVRC passthrough command (PREV) to the Bluetooth device.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_rewind`(esp_periph_handle_t periph)

  Send the AVRC passthrough command (REWIND) to the Bluetooth device.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_fast_forward`(esp_periph_handle_t periph)

  Send the AVRC passthrough command (FAST FORWARD) to the Bluetooth device.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_discover`(esp_periph_handle_t periph)

  Start device discovery.

  Return

    - ESP_OK : Succeed

    - ESP_ERR_INVALID_STATE: if bluetooth stack is not yet enabled

    - ESP_ERR_INVALID_ARG: if invalid parameters are provided

    - ESP_FAIL: others

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_cancel_discover`(esp_periph_handle_t periph)

  Cancel device discovery.

  Return

    - ESP_OK : Succeed

    - ESP_ERR_INVALID_STATE: if bluetooth stack is not yet enabled

    - ESP_FAIL: others

  Parameters

    - `[in] periph`: The periph

esp_err_t `periph_bluetooth_connect`(esp_periph_handle_t periph, bluetooth_addr_t remote_bda)

  Connect remote Device.

  Return

    - ESP_OK : Succeed

    - ESP_ERR_INVALID_STATE: if bluetooth stack is not yet enabled

    - ESP_FAIL: others

  Parameters

    - `[in] periph`: The periph

    - `[in] remote_bda`: remote Bluetooth device address

esp_err_t `bluetooth_service_destroy`()

  Destroy and cleanup bluetooth service, this function must be called after destroying the Bluetoth Stream and Bluetooth Peripheral created by `bluetooth_service_create_stream` and `bluetooth_service_create_periph`

  Return

    - ESP_OK

    - ESP_FAIL

int `periph_bluetooth_get_a2dp_sample_rate`()

  Get a2dp sample rate.

  Return

    - sample rate

###### Structures

struct `bluetooth_service_user_cb_t`

  brief Bluetooth service user callback

  Public Members

  esp_a2d_cb_t `user_a2d_cb`

    callback for a2dp

  esp_a2d_sink_data_cb_t `user_a2d_sink_data_cb`

    callback for a2dp sink data

  esp_a2d_source_data_cb_t `user_a2d_source_data_cb`

    callback for a2dp source data

  esp_avrc_ct_cb_t `user_avrc_ct_cb`

    callback for avrc ct

struct `bluetooth_service_cfg_t`

  brief Bluetooth service configuration

  Public Members

  const char *`device_name`

    Bluetooth local device name

  const char *`remote_name`

    Bluetooth remote device name

  bluetooth_service_mode_t `mode`

    Bluetooth working mode

  bluetooth_service_user_cb_t `user_callback`

    Bluetooth user callback

###### Macros

`ESP_A2DP_SAMPLE_RATE`

`BLUETOOTH_ADDR_LEN`

  brief Bluetooth address length

###### Type Definitions

typedef uint8_t `bluetooth_addr_t`[`BLUETOOTH_ADDR_LEN`]

  brief Bluetooth device address

###### Enumerations

enum `bluetooth_service_mode_t`

  brief Bluetooth service working mode

  Values:

  `BLUETOOTH_A2DP_SINK`

    A2DP Bluetooth sink audio, ESP32 will receive audio data from other bluetooth devices

  `BLUETOOTH_A2DP_SOURCE`

    A2DP Bluetooth source audio, ESP32 can send audio data to other bluetooth devices

###### Header File

- bluetooth_service/include/bt_keycontrol.h

###### Header File

- bluetooth_service/include/hfp_stream.h

###### Header File

- bluetooth_service/include/a2dp_stream.h

#### Input Key Service

[中文]

The input key service provides GPIO input interrupts and ADC key functions in the form of events. For what common key functions are defined by the events for audio products, see `input_key_user_id_t`.

##### Application Example

Implementation of this API is demonstrated in the following example:

- checks/check_board_buttons

- player/pipeline_sdcard_mp3_control

- protocols/voip

###### Header File

- input_key_service/include/input_key_service.h

###### Functions

periph_service_handle_t `input_key_service_create`(input_key_service_cfg_t *input_key_config)

  Initialize and start the input key service.

  Return

    NULL failed others input key service handle

  Parameters

    - `input_key_config`: Configuration of input key service

periph_service_state_t `get_input_key_service_state`(periph_service_handle_t input_handle)

  Get the state of input key service.

  Return

    state of input key service

  Parameters

    - `input_handle`: The handle of input key service

esp_err_t `input_key_service_add_key`(periph_service_handle_t input_key_handle, input_key_service_info_t *input_key_info, int add_key_num)

  Add input key’s information to service list.

  Return

    ESP_OK success ESP_FAIL failed

  Parameters

    - `input_key_handle`: handle of service

    - `input_key_info`: input key’s information

    - `add_key_num`: number of keys

###### Structures

struct `input_key_service_info_t`

  input key’s infomation

  Public Members

  esp_periph_id_t `type`

    ID of peripherals

  int `user_id`

    The key’s user id

  int `act_id`

    The key’s action id

struct `input_key_service_cfg_t`

  input key’s configuration

  Public Members

  periph_service_config_t `based_cfg`

    Peripheral service configuration

  esp_periph_set_handle_t `handle`

    Peripheral set handle

###### Macros

`INPUT_KEY_SERVICE_TASK_STACK_SIZE`

`INPUT_KEY_SERVICE_TASK_PRIORITY`

`INPUT_KEY_SERVICE_TASK_ON_CORE`

`INPUT_KEY_SERVICE_DEFAULT_CONFIG`()

###### Enumerations

enum `input_key_service_action_id_t`

  input key action id

  Values:

  `INPUT_KEY_SERVICE_ACTION_UNKNOWN` = 0

    unknown action id

  `INPUT_KEY_SERVICE_ACTION_CLICK`

    click action id

  `INPUT_KEY_SERVICE_ACTION_CLICK_RELEASE`

    click release action id

  `INPUT_KEY_SERVICE_ACTION_PRESS`

    long press action id

  `INPUT_KEY_SERVICE_ACTION_PRESS_RELEASE`

    long press release id

###### Header File

- input_key_service/include/input_key_com_user_id.h

###### Enumerations

enum `input_key_user_id_t`

  input key user user-defined id

  Values:

  `INPUT_KEY_USER_ID_UNKNOWN` = -1

    unknown user id

  `INPUT_KEY_USER_ID_REC` = 0x01

    user id for recording

  `INPUT_KEY_USER_ID_SET` = 0x02

    user id for settings

  `INPUT_KEY_USER_ID_PLAY` = 0x03

    user id for playing

  `INPUT_KEY_USER_ID_MODE` = 0x04

    user id for mode

  `INPUT_KEY_USER_ID_VOLDOWN` = 0x05

    user id for volume down

  `INPUT_KEY_USER_ID_VOLUP` = 0x06

    user id for volume up

  `INPUT_KEY_USER_ID_MUTE` = 0x07

    user id for mute

  `INPUT_KEY_USER_ID_CAPTURE` = 0x08

    user id for capture photo

  `INPUT_KEY_USER_ID_MSG` = 0x09

    user id for message

  `INPUT_KEY_USER_ID_BATTERY_CHARGING` = 0x0A

    user id for battery charging

  `INPUT_KEY_USER_ID_WAKEUP` = 0x0B

    user id for GPIO wakeup

  `INPUT_KEY_USER_ID_COLOR` = 0x0C

    user id for color

  `INPUT_KEY_USER_ID_MAX` = 0x101

#### Wi-Fi Service

[中文]

The Wi-Fi service can configure and manage the network. SmartConfig, BluFi, and AirKiss are supported for network configuration.

##### Application Example

Implementation of this API is demonstrated in the following example:

- dueros

###### Header File

- wifi_service/include/wifi_service.h

###### Functions

periph_service_handle_t `wifi_service_create`(wifi_service_config_t *config)

esp_err_t `wifi_service_destroy`(periph_service_handle_t handle)

esp_err_t `wifi_service_register_setting_handle`(periph_service_handle_t handle, esp_wifi_setting_handle_t setting, int *out_index)

esp_err_t `wifi_service_setting_start`(periph_service_handle_t handle, int index)

esp_err_t `wifi_service_update_sta_info`(periph_service_handle_t handle, wifi_config_t *wifi_conf)

esp_err_t `wifi_service_setting_stop`(periph_service_handle_t handle, int index)

esp_err_t `wifi_service_connect`(periph_service_handle_t handle)

esp_err_t `wifi_service_disconnect`(periph_service_handle_t handle)

esp_err_t `wifi_service_set_sta_info`(periph_service_handle_t handle, wifi_config_t *info)

periph_service_state_t `wifi_service_state_get`(periph_service_handle_t handle)

wifi_service_disconnect_reason_t `wifi_service_disconnect_reason_get`(periph_service_handle_t handle)

esp_err_t `wifi_service_erase_ssid_manager_info`(periph_service_handle_t handle)

esp_err_t `wifi_service_get_last_ssid_cfg`(periph_service_handle_t handle, wifi_config_t *wifi_cfg)

###### Structures

struct `wifi_service_config_t`

  WiFi service configurations.

  Public Members

  int `task_stack`

    >0 Service task stack; =0 with out task created

  int `task_prio`

    Service task priority (based on freeRTOS priority)

  int `task_core`

    Service task running in core (0 or 1)

  bool `extern_stack`

    Task stack allocate on the extern ram

  periph_service_cb `evt_cb`

    Service callback function

  void *`cb_ctx`

    Callback context

  char *`user_data`

    User data

  int `setting_timeout_s`

    Timeout of setting WiFi

  int `max_retry_time`

    Maximum times of reconnection

  int `max_prov_retry_time`

    Maximum times of reconnection after wifi provision

  uint8_t `max_ssid_num`

    Maximum ssid that can be stored

###### Macros

`WIFI_SERVICE_DEFAULT_CONFIG`()

###### Enumerations

enum `wifi_service_event_t`

  WiFi STA service status.

  Values:

  `WIFI_SERV_EVENT_UNKNOWN`
  `WIFI_SERV_EVENT_CONNECTING`
  `WIFI_SERV_EVENT_CONNECTED`
  `WIFI_SERV_EVENT_DISCONNECTED`
  `WIFI_SERV_EVENT_SETTING_TIMEOUT`
  `WIFI_SERV_EVENT_SETTING_FAILED`
  `WIFI_SERV_EVENT_SETTING_FINISHED`

enum `wifi_service_disconnect_reason_t`

  WiFi STA disconnection reasons.

  Values:

  `WIFI_SERV_STA_UNKNOWN`
  `WIFI_SERV_STA_COM_ERROR`
  `WIFI_SERV_STA_AUTH_ERROR`
  `WIFI_SERV_STA_AP_NOT_FOUND`
  `WIFI_SERV_STA_BY_USER`
  `WIFI_SERV_STA_SET_INFO`

###### Header File

- wifi_service/include/esp_wifi_setting.h

###### Functions

esp_wifi_setting_handle_t `esp_wifi_setting_create`(const char *tag)

  brief Create wifi setting handle instance

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `tag`: Tag of the wifi setting handle

esp_err_t `esp_wifi_setting_destroy`(esp_wifi_setting_handle_t handle)

  brief Destroy wifi setting handle instance

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: The wifi setting handle instance

esp_err_t `esp_wifi_setting_register_function`(esp_wifi_setting_handle_t handle, wifi_setting_func start, wifi_setting_func stop, wifi_setting_teardown_func teardown)

  Register the wifi setting execute functions.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: The wifi setting handle instance

    - `start`: The start wifi setting

    - `stop`: The stop

    - `teardown`: The destroy

esp_err_t `esp_wifi_setting_register_notify_handle`(esp_wifi_setting_handle_t handle, void *on_handle)

  Register the notify execute handle.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: The peripheral handle

    - `on_handle`: The notify execute handle

esp_err_t `esp_wifi_setting_info_notify`(esp_wifi_setting_handle_t handle, wifi_config_t *info)

  Call this to notify the `wifi_config_t` to `on_handle`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: The wifi setting handle instance

    - `info`: The `wifi_config_t`

esp_err_t `esp_wifi_setting_set_data`(esp_wifi_setting_handle_t handle, void *data)

  Set the user data.

  Note

    Make sure the `data` lifetime is sufficient, this function does not copy all data, it only stores the data pointer

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] handle`: The wifi setting handle instance

    - `data`: The user data

void *`esp_wifi_setting_get_data`(esp_wifi_setting_handle_t handle)

  Get the user data stored on `handle`

  Return

    user data pointer

  Parameters

    - `[in] handle`: The wifi setting handle instance

esp_err_t `esp_wifi_setting_start`(esp_wifi_setting_handle_t handle)

  Call this to execute `start` function of wifi setting instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: The wifi setting handle instance

esp_err_t `esp_wifi_setting_stop`(esp_wifi_setting_handle_t handle)

  Call this to execute `stop` function of wifi setting instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: The wifi setting handle instance

esp_err_t `esp_wifi_setting_teardown`(esp_wifi_setting_handle_t handle, wifi_config_t *info)

  Call this to execute `teardown` function of wifi setting instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: The wifi setting handle instance

    - `info`: The `wifi_config_t`

###### Type Definitions

typedef struct esp_wifi_setting *`esp_wifi_setting_handle_t`

typedef esp_err_t (*`wifi_setting_func`)(esp_wifi_setting_handle_t handle)

typedef esp_err_t (*`wifi_setting_teardown_func`)(esp_wifi_setting_handle_t handle, wifi_config_t *info)

###### Header File

- wifi_service/include/smart_config.h

###### Functions

esp_wifi_setting_handle_t `smart_config_create`(smart_config_info_t *info)

  brief Create smartconfig setting handle instance

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `info`: Configuration of the smartconfig

###### Structures

struct `smart_config_info_t`

  esp smartconfig configuration

  Public Members

  smartconfig_type_t `type`

    Type of smartconfig

###### Macros

`SMART_CONFIG_INFO_DEFAULT`()

###### Header File

- wifi_service/include/blufi_config.h

###### Functions

esp_wifi_setting_handle_t `blufi_config_create`(void *info)

  Create blufi setting handle instance.

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `[in] info`: A pointer to void

esp_err_t `blufi_set_sta_connected_flag`(esp_wifi_setting_handle_t handle, bool flag)

  Set flag to judge whether the station has connected to the AP.

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `[in] handle`: Wifi setting handle

    - `[in] flag`: bool type of station connection state

esp_err_t `blufi_set_customized_data`(esp_wifi_setting_handle_t handle, char *data, int data_len)

  Set customized data to be sent after configurate wifi successfully.

  Return

    - ESP_FAIL, Fail

    - ESP_OK, Success

  Parameters

    - `[in] handle`: Wifi setting handle

    - `[in] data`: Customized data

    - `[in] data_len`: Customized data length

esp_err_t `blufi_send_customized_data`(esp_wifi_setting_handle_t handle)

  Send customized data that be set before.

  Return

    - ESP_FAIL, Fail

    - ESP_OK, Success

  Parameters

    - `[in] handle`: Wifi setting handle

###### Header File

- wifi_service/include/airkiss_config.h

###### Functions

esp_wifi_setting_handle_t `airkiss_config_create`(airkiss_config_info_t *info)

  brief Create airkiss setting handle instance

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `info`: Configuration of the airkiss

###### Structures

struct `airkiss_lan_pack_param_t`

  airkiss lan data pack

  Public Members

  void *`appid`

    APP identifer data

  void *`deviceid`

    Device identifer data

struct `airkiss_config_info_t`

  airkiss configurations

  Public Members

  airkiss_lan_pack_param_t `lan_pack`

    User lan pack parameter

  bool `ssdp_notify_enable`

    Notify enable flag

  char *`aes_key`

    Airkiss aes key data

###### Macros

`AIRKISS_CONFIG_INFO_DEFAULT`()

###### Header File

- wifi_service/include/wifi_ssid_manager.h

###### Functions

wifi_ssid_manager_handle_t `wifi_ssid_manager_create`(uint8_t max_ssid_num)

esp_err_t `wifi_ssid_manager_get_latest_config`(wifi_ssid_manager_handle_t handle, wifi_config_t *config)

esp_err_t `wifi_ssid_manager_save`(wifi_ssid_manager_handle_t handle, const char *ssid, const char *pwd)

esp_err_t `wifi_ssid_manager_get_best_config`(wifi_ssid_manager_handle_t handle, wifi_config_t *config)

int `wifi_ssid_manager_get_ssid_num`(wifi_ssid_manager_handle_t handle)

esp_err_t `wifi_ssid_manager_list_show`(wifi_ssid_manager_handle_t handle)

esp_err_t `wifi_ssid_manager_erase_all`(wifi_ssid_manager_handle_t handle)

esp_err_t `wifi_ssid_manager_destroy`(wifi_ssid_manager_handle_t handle)

###### Type Definitions

typedef struct wifi_ssid_manager *`wifi_ssid_manager_handle_t`

#### OTA Service

[中文]

OTA service can upgrade firmware over the air (OTA). The firmware can be fetched from local files or the network.

##### Application Example

Implementation of this API is demonstrated in the following example:

- ota

###### Header File

- ota_service/include/ota_service.h

###### Functions

periph_service_handle_t `ota_service_create`(ota_service_config_t *config)

  Create the OTA service instance.

  Return

    - NULL: Failed

    - Others: Success

  Parameters

    - `config`: configuration of the OTA service

esp_err_t `ota_service_set_upgrade_param`(periph_service_handle_t handle, ota_upgrade_ops_t *list, int list_len)

  Configure the upgrade parameter This function is not thread safe.

  This function will set the parameter table to ota service, and the ota service will upgrade the partitions defined in the table one by one,

  Return

    - ESP_OK: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to ‘periph_service_handle_t’ structure

    - `[in] list`: pointer to ‘ota_upgrade_ops_t’ structure

    - `[in] list_len`: length of the ‘list’

###### Structures

struct `ota_service_config_t`

  The OTA service configuration.

  Public Members

  int `task_stack`

    >0 Service task stack; =0 with out task created

  int `task_prio`

    Service task priority (based on freeRTOS priority)

  int `task_core`

    Service task running in core (0 or 1)

  periph_service_cb `evt_cb`

    Service callback function

  void *`cb_ctx`

    Callback context

struct `ota_node_attr_t`

  The OTA node attributions.

  Public Members

  esp_partition_type_t `type`

    Partition type

  char *`label`

    Partition label

  char *`uri`

    The upgrade URL

  char *`cert_pem`

    SSL server certification, PEM format as string, if the client requires to verify server

struct `ota_upgrade_ops_t`

  The upgrade operation.

  Public Members

  ota_node_attr_t `node`

    The OTA node

  ota_service_err_reason_t (*`prepare`)(void **handle, ota_node_attr_t *node)

    Functions ready for upgrade

  ota_service_err_reason_t (*`need_upgrade`)(void *handle, ota_node_attr_t *node)

    Detect whether an upgrade is required

  ota_service_err_reason_t (*`execute_upgrade`)(void *handle, ota_node_attr_t *node)

    For execute upgrade

  ota_service_err_reason_t (*`finished_check`)(void *handle, ota_node_attr_t *node, ota_service_err_reason_t result)

    Check result of upgrade

  bool `reboot_flag`

    Reboot or not after upgrade

  bool `break_after_fail`

    Abort upgrade when got failed

struct `ota_result_t`

  The result of the OTA upgrade.

  Public Members

  uint8_t `id`

    The result ID

  ota_service_err_reason_t `result`

    The error reason

###### Macros

`OTA_SERVICE_ERR_REASON_BASE`

`OTA_SERVICE_DEFAULT_CONFIG`()

###### Enumerations

enum `ota_service_event_type_t`

  The OTA service event type.

  Values:

  `OTA_SERV_EVENT_TYPE_RESULT`
  `OTA_SERV_EVENT_TYPE_FINISH`

enum `ota_service_err_reason_t`

  The OTA service error reasons.

  Values:

  `OTA_SERV_ERR_REASON_UNKNOWN` = ESP_FAIL
  `OTA_SERV_ERR_REASON_SUCCESS` = ESP_OK
  `OTA_SERV_ERR_REASON_NULL_POINTER` = OTA_SERVICE_ERR_REASON_BASE + 1
  `OTA_SERV_ERR_REASON_URL_PARSE_FAIL` = OTA_SERVICE_ERR_REASON_BASE + 2
  `OTA_SERV_ERR_REASON_ERROR_VERSION` = OTA_SERVICE_ERR_REASON_BASE + 3
  `OTA_SERV_ERR_REASON_NO_HIGHER_VERSION` = OTA_SERVICE_ERR_REASON_BASE + 4
  `OTA_SERV_ERR_REASON_ERROR_MAGIC_WORD` = OTA_SERVICE_ERR_REASON_BASE + 5
  `OTA_SERV_ERR_REASON_ERROR_PROJECT_NAME` = OTA_SERVICE_ERR_REASON_BASE + 6
  `OTA_SERV_ERR_REASON_FILE_NOT_FOUND` = OTA_SERVICE_ERR_REASON_BASE + 7
  `OTA_SERV_ERR_REASON_PARTITION_NOT_FOUND` = OTA_SERVICE_ERR_REASON_BASE + 8
  `OTA_SERV_ERR_REASON_PARTITION_WT_FAIL` = OTA_SERVICE_ERR_REASON_BASE + 9
  `OTA_SERV_ERR_REASON_PARTITION_RD_FAIL` = OTA_SERVICE_ERR_REASON_BASE + 10
  `OTA_SERV_ERR_REASON_STREAM_INIT_FAIL` = OTA_SERVICE_ERR_REASON_BASE + 11
  `OTA_SERV_ERR_REASON_STREAM_RD_FAIL` = OTA_SERVICE_ERR_REASON_BASE + 12
  `OTA_SERV_ERR_REASON_GET_NEW_APP_DESC_FAIL` = OTA_SERVICE_ERR_REASON_BASE + 13

###### Header File

- ota_service/include/ota_proc_default.h

###### Functions

void `ota_app_get_default_proc`(ota_upgrade_ops_t *ops)

  get the default process of `app partition` upgrade

  Return

    - void

  Parameters

    - `[in] ops`: pointer to `ota_upgrade_ops_t` structure

void `ota_data_get_default_proc`(ota_upgrade_ops_t *ops)

  get the default process of `data partition` upgrade

  Return

    - void

  Parameters

    - `[in] ops`: pointer to `ota_upgrade_ops_t` structure

ota_service_err_reason_t `ota_data_image_stream_read`(void *handle, char *buf, int wanted_size)

  read from the stream of upgrading

  Return

    - OTA_SERV_ERR_REASON_SUCCESS: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to upgrade handle

    - `[in] buf`: pointer to receive buffer

    - `[in] wanted_size`: bytes to read

ota_service_err_reason_t `ota_data_partition_write`(void *handle, char *buf, int size)

  write to the data partition under upgrading

  Return

    - OTA_SERV_ERR_REASON_SUCCESS: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to upgrade handle

    - `[in] buf`: pointer to data buffer

    - `[in] size`: bytes to write

void `ota_data_partition_erase_mark`(void *handle)

  Indicates that the ota partition has been erased By default, this part of flash will be erased during ota. If the behavior of erasing is called in applition, this API needs to be called.

  Return

    - void

  Parameters

    - `[in] handle`: pointer to upgrade handle

int `ota_get_version_number`(char *version)

  Convert string of version to integer The version should be (V0.0.0 - V255.255.255)

  Return

    - -1: Failed

    - Others: version number

  Parameters

    - `[in] version`: pointer to the string of version

###### Header File

- ota_service/include/esp_fs_ota.h

###### Functions

esp_err_t `esp_fs_ota`(esp_fs_ota_config_t *ota_config)

  Upgrade the firmware from filesystem.

  Note

    This API handles the entire OTA operation, so if this API is being used then no other APIs from `esp_fs_ota` component should be called. If more information and control is needed during the FS OTA process, then one can use `esp_fs_ota_begin` and subsequent APIs. If this API returns successfully, esp_restart() must be called to boot from the new firmware image.

  Return

    - ESP_OK: OTA data updated, next reboot will use specified partition.

    - ESP_FAIL: For generic failure.

    - ESP_ERR_INVALID_ARG: Invalid argument

    - ESP_ERR_OTA_VALIDATE_FAILED: Invalid app image

    - ESP_ERR_NO_MEM: Cannot allocate memory for OTA operation.

    - ESP_ERR_FLASH_OP_TIMEOUT or ESP_ERR_FLASH_OP_FAIL: Flash write failed.

    - For other return codes, refer OTA documentation in esp-idf’s app_update component.

  Parameters

    - `[in] ota_config`: pointer to esp_fs_ota_config_t structure.

esp_err_t `esp_fs_ota_begin`(esp_fs_ota_config_t *ota_config, esp_fs_ota_handle_t *handle)

  Start FS OTA Firmware upgrade.

  This function initializes ESP FS OTA context and open the firmware file. This function must be invoked first. If this function returns successfully, then `esp_fs_ota_perform` should be called to continue with the OTA process and there should be a call to `esp_fs_ota_finish` on completion of OTA operation or on failure in subsequent operations.

  Return

    - ESP_OK: FS OTA Firmware upgrade context initialised and file opened successful

    - ESP_FAIL: For generic failure.

    - ESP_ERR_INVALID_ARG: Invalid argument (missing/incorrect config, etc.)

    - For other return codes, refer documentation in app_update component and esp_http_client component in esp-idf.

  Parameters

    - `[in] ota_config`: pointer to esp_fs_ota_config_t structure

    - `[out] handle`: pointer to an allocated data of type `esp_fs_ota_handle_t` which will be initialised in this function

esp_err_t `esp_fs_ota_perform`(esp_fs_ota_handle_t fs_ota_handle)

  Read image data from file stream and write it to OTA partition.

  This function reads image data from file stream and writes it to OTA partition. This function must be called only if esp_fs_ota_begin() returns successfully. This function must be called in a loop since it returns after every file read operation thus giving you the flexibility to stop OTA operation midway.

  Return

    - ESP_ERR_FS_OTA_IN_PROGRESS: OTA update is in progress, call this API again to continue.

    - ESP_OK: OTA update was successful

    - ESP_FAIL: OTA update failed

    - ESP_ERR_INVALID_ARG: Invalid argument

    - ESP_ERR_OTA_VALIDATE_FAILED: Invalid app image

    - ESP_ERR_NO_MEM: Cannot allocate memory for OTA operation.

    - ESP_ERR_FLASH_OP_TIMEOUT or ESP_ERR_FLASH_OP_FAIL: Flash write failed.

    - For other return codes, refer OTA documentation in esp-idf’s app_update component.

  Parameters

    - `[in] fs_ota_handle`: pointer to esp_fs_ota_handle_t structure

esp_err_t `esp_fs_ota_finish`(esp_fs_ota_handle_t fs_ota_handle)

  Clean-up FS OTA Firmware upgrade and close the file stream.

  This function closes the file stream and frees the ESP FS OTA context. This function switches the boot partition to the OTA partition containing the new firmware image.

  Note

    If this API returns successfully, esp_restart() must be called to boot from the new firmware image

  Return

    - ESP_OK: Clean-up successful

    - ESP_ERR_INVALID_STATE

    - ESP_ERR_INVALID_ARG: Invalid argument

    - ESP_ERR_OTA_VALIDATE_FAILED: Invalid app image

  Parameters

    - `[in] fs_ota_handle`: pointer to esp_fs_ota_handle_t structure

esp_err_t `esp_fs_ota_get_img_desc`(esp_fs_ota_handle_t fs_ota_handle, esp_app_desc_t *new_app_info)

  Reads app description from image header. The app description provides information like the “Firmware version” of the image.

  Note

    This API can be called only after esp_fs_ota_begin() and before esp_fs_ota_perform(). Calling this API is not mandatory.

  Return

    - ESP_ERR_INVALID_ARG: Invalid arguments

    - ESP_FAIL: Failed to read image descriptor

    - ESP_OK: Successfully read image descriptor

  Parameters

    - `[in] fs_ota_handle`: pointer to esp_fs_ota_handle_t structure

    - `[out] new_app_info`: pointer to an allocated esp_app_desc_t structure

int `esp_fs_ota_get_image_len_read`(esp_fs_ota_handle_t fs_ota_handle)

###### Structures

struct `esp_fs_ota_config_t`

  ESP FS OTA configuration.

  Public Members

  const char *`path`

    file path

  const int `buffer_size`

    Size of buffer

###### Macros

`ESP_ERR_FS_OTA_BASE`

`ESP_ERR_FS_OTA_IN_PROGRESS`

###### Type Definitions

typedef void *`esp_fs_ota_handle_t`

#### DuerOS Service

[中文]

The DuerOS service allows voice interaction with DuerOS.

##### Application Example

Implementation of this API is demonstrated in the following example:

- dueros

###### Header File

- dueros_service/include/dueros_service.h

###### Functions

audio_service_handle_t `dueros_service_create`()

  Create the dueros service.

  Return

    - NULL, Fail

    - Others, Success

service_state_t `dueros_service_state_get`()

  Get dueros service state.

  Return

    The state of service

esp_err_t `dueros_voice_upload`(audio_service_handle_t handle, void *buf, int len)

  Upload voice to backend server.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: dueros service handle

    - `buf`: Data buffer

    - `len`: Size of buffer

esp_err_t `dueros_voice_cancel`(audio_service_handle_t handle)

  Cancel the current session.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: dueros service handle

esp_err_t `dueros_start_wifi_cfg`(audio_service_handle_t handle, duer_wifi_cfg_t *cfg)

  Start the wifi configure process.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Dueros service handle

    - `cfg`: Configuration

esp_err_t `dueros_stop_wifi_cfg`(audio_service_handle_t handle)

  Stop the wifi configure process.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Dueros service handle

esp_err_t `dueros_wifi_status_report`(audio_service_handle_t handle, dueros_wifi_st_t *st)

  Report the wifi status to dipb.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Dueros service handle

    - `st`: WiFi status and error code

###### Structures

struct `dueros_wifi_st_t`

  Status of WiFi connection.

  Public Members

  int `status`

    Please refer to: `enum duer_dipb_client_status_e`

  int `err`

    Please refer to: `enum duer_wifi_connect_error_code_e`

#### Display Service

[中文]

The display service defines enumeration values for some common display patterns in `display_pattern_t`, with which you can set the corresponding patterns of LEDs or LED bars.

The currently supported LED drivers are AW2013, WS2812, and IS31x.

##### Application Example

Implementation of this API is demonstrated in the following example:

- checks/check_display_led

###### Header File

- display_service/include/display_service.h

###### Functions

display_service_handle_t `display_service_create`(display_service_config_t *cfg)

esp_err_t `display_service_set_pattern`(void *handle, int disp_pattern, int value)

esp_err_t `display_destroy`(display_service_handle_t handle)

###### Structures

struct `display_service_config_t`

  Display service configurations.

  Public Members

  periph_service_config_t `based_cfg`

    Peripheral service configuration

  void *`instance`

    Sub-instance

###### Type Definitions

typedef struct display_service_impl *`display_service_handle_t`

###### Enumerations

enum `display_pattern_t`

  Values:

  `DISPLAY_PATTERN_UNKNOWN` = 0
  `DISPLAY_PATTERN_WIFI_SETTING` = 1
  `DISPLAY_PATTERN_WIFI_CONNECTTING` = 2
  `DISPLAY_PATTERN_WIFI_CONNECTED` = 3
  `DISPLAY_PATTERN_WIFI_DISCONNECTED` = 4
  `DISPLAY_PATTERN_WIFI_SETTING_FINISHED` = 5
  `DISPLAY_PATTERN_BT_CONNECTTING` = 6
  `DISPLAY_PATTERN_BT_CONNECTED` = 7
  `DISPLAY_PATTERN_BT_DISCONNECTED` = 8
  `DISPLAY_PATTERN_RECORDING_START` = 9
  `DISPLAY_PATTERN_RECORDING_STOP` = 10
  `DISPLAY_PATTERN_RECOGNITION_START` = 11
  `DISPLAY_PATTERN_RECOGNITION_STOP` = 12
  `DISPLAY_PATTERN_WAKEUP_ON` = 13
  `DISPLAY_PATTERN_WAKEUP_FINISHED` = 14
  `DISPLAY_PATTERN_MUSIC_ON` = 15
  `DISPLAY_PATTERN_MUSIC_FINISHED` = 16
  `DISPLAY_PATTERN_VOLUME` = 17
  `DISPLAY_PATTERN_MUTE_ON` = 18
  `DISPLAY_PATTERN_MUTE_OFF` = 19
  `DISPLAY_PATTERN_TURN_ON` = 20
  `DISPLAY_PATTERN_TURN_OFF` = 21
  `DISPLAY_PATTERN_BATTERY_LOW` = 22
  `DISPLAY_PATTERN_BATTERY_CHARGING` = 23
  `DISPLAY_PATTERN_BATTERY_FULL` = 24
  `DISPLAY_PATTERN_POWERON_INIT` = 25
  `DISPLAY_PATTERN_WIFI_NO_CFG` = 26
  `DISPLAY_PATTERN_SPEECH_BEGIN` = 27
  `DISPLAY_PATTERN_SPEECH_OVER` = 28
  `DISPLAY_PATTERN_MAX`

###### Header File

- display_service/led_bar/include/led_bar_aw2013.h

###### Functions

void `aw2013_led_bar_task`(void *parameters)

esp_periph_handle_t `led_bar_aw2013_init`(void)

  Initialize led bar instance.

  Return

    - NULL Error

    - others Success

esp_err_t `led_bar_aw2013_pattern`(void *handle, int pat, int value)

  Set led bar display pattern.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: led bar instance

    - `pat`: display pattern

    - `value`: value of pattern

esp_err_t `led_bar_aw2013_set_blink_time`(void *handle, uint8_t time, int period)

  Set blinking period and times.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: led bar instance

    - `time`: times of blink

    - `period`: period of blink

void `led_bar_aw2013_deinit`(esp_periph_handle_t handle)

  Destroy esp_periph_handle_t instance.

  Parameters

    - `handle`: led bar instance

###### Header File

- display_service/led_bar/include/led_bar_is31x.h

###### Functions

esp_periph_handle_t `led_bar_is31x_init`()

  Initialize esp_periph_handle_t instance.

  Return

    - NULL, Fail

    - Others, Success

esp_err_t `led_bar_is31x_pattern`(void *handle, int pat, int value)

  Set led bar display pattern.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: led bar instance

    - `pat`: display pattern

    - `value`: value of pattern

void `led_bar_is31x_deinit`(esp_periph_handle_t handle)

  Destroy esp_periph_handle_t instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: led bar instance

###### Header File

- display_service/led_bar/include/led_bar_ws2812.h

###### Functions

led_bar_ws2812_handle_t `led_bar_ws2812_init`(gpio_num_t gpio_num, int led_num)

  Initialize led_bar_ws2812_handle_t instance.

  Return

    - led_bar_ws2812_handle_t

  Parameters

    - `gpio_num`: The GPIO number of ws2812

    - `led_num`: The number of all ws2812

esp_err_t `led_bar_ws2812_pattern`(void *handle, int pat, int value)

  Set ws2812 pattern.

  Return

    - ESP_OK, success

    - Others, fail

  Parameters

    - `handle`: ws2812 indicator instance

    - `pat`: display pattern

    - `value`: value of pattern

esp_err_t `led_bar_ws2812_deinit`(led_bar_ws2812_handle_t handle)

  Destroy led_bar_ws2812_handle_t instance.

  Return

  Return

    - ESP_OK, success

    - Others, fail

  Parameters

    - `handle`: ws2812 indicator instance

###### Type Definitions

typedef struct led_bar_ws2812_impl *`led_bar_ws2812_handle_t`

###### Header File

- display_service/led_indicator/include/led_indicator.h

###### Functions

led_indicator_handle_t `led_indicator_init`(gpio_num_t num)

  Initialize led_indicator_handle_t instance.

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `num`: led gpio number

esp_err_t `led_indicator_pattern`(void *handle, int pat, int value)

  Set led indicator display pattern.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: led indicator instance

    - `pat`: display pattern

    - `value`: value of pattern

void `led_indicator_deinit`(led_indicator_handle_t handle)

  Destroy led_indicator_handle_t instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `handle`: led indicator instance

###### Type Definitions

typedef struct led_indicator_impl *`led_indicator_handle_t`

#### Battery Service

[中文]

The battery service can monitor and manage battery voltage. You can access battery voltage and the events defined by `battery_service_event_t` through callback functions.

##### Application Example

Implementation of this API is demonstrated in the following example:

- system/battery

###### Header File

- battery_service/include/battery_service.h

###### Functions

periph_service_handle_t `battery_service_create`(battery_service_config_t *config)

  Create the battery service instance.

  Return

    - NULL: Failed

    - Others: Success

  Parameters

    - `config`: configuration of the battery service

esp_err_t `battery_service_vol_report_switch`(periph_service_handle_t handle, bool on_off)

  Start or stop the battery voltage report.

  Return

    - ESP_OK: Success

    - ESP_ERR_INVALID_ARG： handle is NULL

  Parameters

    - `[in] handle`: pointer to ‘periph_service_handle_t’ structure

    - `[in] on_off`: ‘true’ to start, ‘false’ to stop

esp_err_t `battery_service_set_vol_report_freq`(periph_service_handle_t handle, int freq)

  Set voltage report freqency.

  Return

    - ESP_OK: Success

    - ESP_ERR_INVALID_ARG： handle is NULL

  Parameters

    - `[in] handle`: pointer to ‘periph_service_handle_t’ structure

    - `[in] freq`: voltage report freqency

###### Structures

struct `battery_service_config_t`

  Battery service configure.

  Public Members

  int `task_stack`

    >0 Service task stack; =0 with out task created

  int `task_prio`

    Service task priority (based on freeRTOS priority)

  int `task_core`

    Service task running in core (0 or 1)

  bool `extern_stack`

    Task stack allocate on the extern ram

  periph_service_cb `evt_cb`

    Service callback function

  void *`cb_ctx`

    Callback context

  vol_monitor_handle_t `vol_monitor`

    Battery monitor

  void *`charger_monitor`

    Charger monitor. Not supported yet

###### Macros

`BATTERY_SERVICE_DEFAULT_CONFIG`()

###### Enumerations

enum `battery_service_event_t`

  Battery service event.

  Values:

  `BAT_SERV_EVENT_UNKNOWN`
  `BAT_SERV_EVENT_VOL_REPORT` = 1
  `BAT_SERV_EVENT_BAT_FULL`
  `BAT_SERV_EVENT_BAT_LOW`
  `BAT_SERV_EVENT_CHARGING_BEGIN` = 100
  `BAT_SERV_EVENT_CHARGING_STOP`

###### Header File

- battery_service/monitors/include/voltage_monitor.h

###### Functions

vol_monitor_handle_t `vol_monitor_create`(vol_monitor_param_t *config)

  Create the voltage monitor instance.

  Return

    - NULL: Failed

    - Others: Success

  Parameters

    - `[in] config`: pointer to ‘vol_monitor_param_t’ structure

esp_err_t `vol_monitor_destroy`(vol_monitor_handle_t handle)

  Destroy the voltage monitor.

  Return

    - ESP_OK: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to ‘vol_monitor_handle_t’ structure

esp_err_t `vol_monitor_set_event_cb`(vol_monitor_handle_t handle, vol_monitor_event_cb event_cb, void *user_ctx)

  Set the event callback.

  Return

    - ESP_OK: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to ‘vol_monitor_handle_t’ structure

    - `[in] event_cb`: callback used to handle the events of voltage monitor

    - `[in] user_ctx`: user’s data

esp_err_t `vol_monitor_start_freq_report`(vol_monitor_handle_t handle)

  Start the voltage report with the configured frequency.

  Return

    - ESP_OK: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to ‘vol_monitor_handle_t’ structure

esp_err_t `vol_monitor_stop_freq_report`(vol_monitor_handle_t handle)

  Stop the voltage frequency report.

  Return

    - ESP_OK: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to ‘vol_monitor_handle_t’ structure

esp_err_t `vol_monitor_set_report_freq`(vol_monitor_handle_t handle, int freq)

  Set the voltage report frequency.

  Return

    - ESP_OK: Success

    - Others: Failed

  Parameters

    - `[in] handle`: pointer to ‘vol_monitor_handle_t’ structure

    - `[in] freq`: voltage report freqency

###### Structures

struct `vol_monitor_param_t`

  Battery adc configure.

  Public Members

  bool (*`init`)(void *)

    Voltage read init

  bool (*`deinit`)(void *)

    Voltage read deinit

  int (*`vol_get`)(void *)

    Voltage read interface

  void *`user_data`

    Parameters for callbacks

  int `read_freq`

    Voltage read frequency, unit: s

  int `report_freq`

    Voltage report frequency, voltage will be report with a interval calculate by （`read_freq` * `report_freq`）

  int `vol_full_threshold`

    Voltage threshold to report, unit: mV

  int `vol_low_threshold`

    Voltage threshold to report, unit: mV

###### Type Definitions

typedef void *`vol_monitor_handle_t`

  voltage monitor handle

typedef void (*`vol_monitor_event_cb`)(int msg_id, void *data, void *user_ctx)

  callback define

###### Enumerations

enum `vol_monitor_event_t`

  Battery adc configure.

  Values:

  `VOL_MONITOR_EVENT_FREQ_REPORT`
  `VOL_MONITOR_EVENT_BAT_FULL`
  `VOL_MONITOR_EVENT_BAT_LOW`

#### Core Dump Upload Service

[中文]

To investigate crashes in some sold devices, the backtrace is needed for analysis. The core dump upload service transmits the backtrace stored in the device partition over HTTP. To enable this feature, select `ESP_COREDUMP_ENABLE_TO_FLASH`.

##### Application Example

Implementation of this API is demonstrated in the following example:

- system/coredump

###### Header File

- coredump_upload_service/include/coredump_upload_service.h

###### Functions

bool `coredump_need_upload`()

  This function will check the reset code and determine whether to upload the coredump.

  Return

    - true: last reboot is a abnormal reset.

    - false

esp_err_t `coredump_upload`(periph_service_handle_t handle, char *url)

  Upload the core dump image to the url. This function will block the current task until the upload process finished.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] handle`: the ‘periph_service_handle_t’

    - `[in] url`: server addr

periph_service_handle_t `coredump_upload_service_create`(coredump_upload_service_config_t *config)

  Create the core dump upload service instance.

  Return

    - NULL: Failed

    - Others: Success

  Parameters

    - `config`: configuration of the OTA service

###### Structures

struct `coredump_upload_service_config_t`

  coredump service configuration parameters

  Public Members

  int `task_stack`

    >0 Service task stack; =0 with out task created

  int `task_prio`

    Service task priority (based on freeRTOS priority)

  int `task_core`

    Service task running in core (0 or 1)

  periph_service_cb `evt_cb`

    Service callback function

  void *`cb_ctx`

    Callback context

  bool (*`do_post`)(char *url, uint8_t *data, size_t len)

    POST interface, users can override this to customize the http client. if left NULL, the service will use the default one

###### Macros

`COREDUMP_UPLOAD_SERVICE_DEFAULT_CONFIG`()

#### Header File

- esp_dispatcher/include/periph_service.h

#### Functions

periph_service_handle_t `periph_service_create`(periph_service_config_t *config)

  brief Create peripheral service instance

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `[in] config`: Configuration of the peripheral service instance

esp_err_t `periph_service_destroy`(periph_service_handle_t handle)

  brief Destroy peripheral service instance

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The peripheral service instance

esp_err_t `periph_service_start`(periph_service_handle_t handle)

  brief Start the specific peripheral service

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The peripheral service instance

esp_err_t `periph_service_stop`(periph_service_handle_t handle)

  brief Stop the specific peripheral service

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The peripheral service instance

esp_err_t `periph_service_set_callback`(periph_service_handle_t handle, periph_service_cb cb, void *ctx)

  brief Set the specific peripheral service callback function

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The peripheral service instance

    - `[in] cb`: A pointer to service_callback

    - `[in] ctx`: A pointer to user context

esp_err_t `periph_service_callback`(periph_service_handle_t handle, periph_service_event_t *evt)

  brief Called peripheral service by configurations

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The peripheral service instance

    - `[in] evt`: A pointer to periph_service_event_t

esp_err_t `periph_service_set_data`(periph_service_handle_t handle, void *data)

  brief Set user data to specific peripheral service instance

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The peripheral service instance

    - `[in] data`: A pointer to user data

void *`periph_service_get_data`(periph_service_handle_t handle)

  brief Get user data by specific peripheral service instance

  Return

    A pointer to user data

  Parameters

    - `[in] handle`: The peripheral service instance

esp_err_t `periph_service_ioctl`(periph_service_handle_t handle, void *ioctl_handle, int cmd, int value)

  brief In/out control by peripheral service instance

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The peripheral service instance

    - `[in] ioctl_handle`: Sub-instance handle

    - `[in] cmd`: Command of value

    - `[in] value`: Data of the command

#### Structures

struct `periph_service_event_t`

  Peripheral service event informations.

  Public Members

  int `type`

    Type of event

  void *`source`

    Event source

  void *`data`

    Event data

  int `len`

    Length of data

struct `periph_service_config_t`

  Peripheral service configurations.

  Public Members

  int `task_stack`

    >0 Service task stack; =0 with out task created

  int `task_prio`

    Service task priority (based on freeRTOS priority)

  int `task_core`

    Service task running in core (0 or 1)

  TaskFunction_t `task_func`

    Service task function

  bool `extern_stack`

    Task stack allocate on the extern ram

  periph_service_ctrl `service_start`

    Start function

  periph_service_ctrl `service_stop`

    Stop function

  periph_service_ctrl `service_destroy`

    Destroy function

  periph_service_io `service_ioctl`

    In out control function

  char *`service_name`

    Name of peripheral service

  void *`user_data`

    User data

#### Type Definitions

typedef struct periph_service_impl *`periph_service_handle_t`

typedef esp_err_t (*`periph_service_ctrl`)(periph_service_handle_t handle)

typedef esp_err_t (*`periph_service_io`)(void *ioctl_handle, int cmd, int value)

typedef esp_err_t (*`periph_service_cb`)(periph_service_handle_t handle, periph_service_event_t *evt, void *ctx)

#### Enumerations

enum `periph_service_state_t`

  Peripheral service state.

  Values:

  `PERIPH_SERVICE_STATE_UNKNOWN`
  `PERIPH_SERVICE_STATE_IDLE`
  `PERIPH_SERVICE_STATE_RUNNING`
  `PERIPH_SERVICE_STATE_STOPPED`

#### Header File

- esp_dispatcher/include/audio_service.h

#### Functions

audio_service_handle_t `audio_service_create`(audio_service_config_t *config)

  brief Create audio service instance

  Return

    - NULL, Fail

    - Others, Success

  Parameters

    - `[in] config`: Configuration of the audio service instance

esp_err_t `audio_service_destroy`(audio_service_handle_t handle)

  brief Destroy audio service instance

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

esp_err_t `audio_service_start`(audio_service_handle_t handle)

  brief Start the specific audio service

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

esp_err_t `audio_service_stop`(audio_service_handle_t handle)

  brief Stop the specific audio service

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

esp_err_t `audio_service_set_callback`(audio_service_handle_t handle, service_callback cb, void *ctx)

  brief Set the specific audio service callback function.

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

    - `[in] cb`: A pointer to service_callback

    - `[in] ctx`: A pointer to user context

esp_err_t `audio_service_callback`(audio_service_handle_t handle, service_event_t *evt)

  brief Called audio service by configurations

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

    - `[in] evt`: A pointer to service_event_t

esp_err_t `audio_service_connect`(audio_service_handle_t handle)

  brief Connect the specific audio service

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

esp_err_t `audio_service_disconnect`(audio_service_handle_t handle)

  brief Disconnect the specific audio service

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

esp_err_t `audio_service_set_data`(audio_service_handle_t handle, void *data)

  brief Set user data to specific audio service instance

  Return

    - ESP_OK

    - ESP_FAIL

    - ESP_ERR_INVALID_ARG

  Parameters

    - `[in] handle`: The audio service instance

    - `[in] data`: A pointer to user data

void *`audio_service_get_data`(audio_service_handle_t handle)

  brief Get user data by specific audio service instance

  Return

    A pointer to user data

  Parameters

    - `[in] handle`: The audio service instance

#### Structures

struct `service_event_t`

  Audio service event informations.

  Public Members

  int `type`

    Type of event

  void *`source`

    Event source

  void *`data`

    Event data

  int `len`

    Length of data

struct `audio_service_config_t`

  Audio service configurations.

  Public Members

  int `task_stack`

    >0 Service task stack; =0 with out task created

  int `task_prio`

    Service task priority (based on freeRTOS priority)

  int `task_core`

    Service task running in core (0 or 1)

  TaskFunction_t `task_func`

    A pointer to TaskFunction_t for service task function

  service_ctrl `service_start`

    Start function

  service_ctrl `service_stop`

    Stop function

  service_ctrl `service_connect`

    Connect function

  service_ctrl `service_disconnect`

    Disconnect function

  service_ctrl `service_destroy`

    Destroy function

  const char *`service_name`

    Name of audio service

  void *`user_data`

    User context

#### Type Definitions

typedef struct audio_service_impl *`audio_service_handle_t`

typedef esp_err_t (*`service_ctrl`)(audio_service_handle_t handle)

typedef esp_err_t (*`service_callback`)(audio_service_handle_t handle, service_event_t *evt, void *ctx)

#### Enumerations

enum `service_state_t`

  Audio service state.

  Values:

  `SERVICE_STATE_UNKNOWN`
  `SERVICE_STATE_IDLE`
  `SERVICE_STATE_CONNECTING`
  `SERVICE_STATE_CONNECTED`
  `SERVICE_STATE_RUNNING`
  `SERVICE_STATE_STOPPED`

### Speech Recognition

ESP-ADF offers a comprehensive range of speech recognition processing functions, such as front-end speech processing, TTS, voice wake-up, and command word recognition. ESP-ADF’s Element-based audio recorder integrates speech recognition and audio signal processing into an event-driven High-level API. This approach enables users to maintain flexibility in their configurations while making it easier to use.

#### Voice Activity Detection

Voice activity detection (VAD) is a technique used in speech processing to detect the presence (or absence) of human speech. Detection of somebody speaking may be used to activate some processes, e.g. automatically switch on voice recording. It may be also used to deactivate processes, e.g. stop coding and transmission of silence packets to save on computation and network bandwidth.

Provided in this section API implements VAD functionality together with couple of options to configure sensitivity of speech detection, set sample rate or duration of audio samples.

##### Application Example

Implementation of the voice activity detection API is demonstrated in speech_recognition/vad example.

##### API Reference

For the latest API reference please refer to Espressif Speech recognition repository.

#### WakeNet Interface

Setting up the speech recognition application to detect a wakeup word may be done using series of Audio Elements linked into a pipeline shown below.

Sample Speech Recognition Pipeline

Configuration and use of particular elements is demonstrated in several examples linked to elsewhere in this documentation. What may need clarification is use of the Filter and the RAW stream. The filter is used to adjust the sample rate of the I2S stream to match the sample rate of the speech recognition model. The RAW stream is the way to feed the audio input to the model.

The above introduction is the primary guidance. ESP-ADF offers users a more flexible and convenient module, namely the audio recorder, which is strongly recommended for use.

##### API Reference

For the latest speech recognition API reference, please refer to ESP-SR Speech Recognition Framework.

#### Audio Recorder

The Audio Recorder API is a set of functions to facilitate voice recording. It combines two important functions, namely Audio Front End (AFE) and audio encoding. This allows users to customize AFE’s Voice Activity Detection (VAD), Automatic Gain Control (AGC), and Acoustic Echo Cancellation (AEC) settings. The encoding function is used by users to establish the encoding audio element, which supports various formats such as AAC, AMR-NB, AMR-WB, ADPCM, WAV, OPUS, and G711. The audio_rec_evt_t event makes it easy for users to interact with the Audio Recorder software.

The data path of the Audio recorder is presented in the diagram below.

Audio recorder data path

The area represented by the parallelogram is configurable by the user according to their needs, such as sampling frequency, whether to encode, and encoding format.

##### Application Example

The speech_recognition/wwe/ example demonstrates how to initialize the speech recognition model, determine the number of samples and the sample rate of voice data to feed to the model, detect the wake-up word and command words, and encode voice to specific audio format.

##### API Reference

###### Header File

- audio_recorder/include/audio_recorder.h

###### Functions

audio_rec_handle_t `audio_recorder_create`(audio_rec_cfg_t *cfg)

  Initialize and start up audio recorder.

  Return

    NULL failed Others audio recorder handle

  Parameters

    - `cfg`: Configuration of audio recorder

esp_err_t `audio_recorder_trigger_start`(audio_rec_handle_t handle)

  Start recording by force.

  Note

    If there need to read from recorder without wake word detected or read from recorder while the wake word detection is disabled, this interface can be use to force start the recorder process.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Audio recorder handle

esp_err_t `audio_recorder_trigger_stop`(audio_rec_handle_t handle)

  Stop recording by force.

  Note

    No matter the recorder process is triggered by wake word detected or triggered by `audio_recorder_trigger_start`, this function can be used to force stop the recorder. And if the VAD detection is disabeled, this must be invoked to stop recording after `audio_recorder_trigger_start`.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Audio recorder handle

esp_err_t `audio_recorder_wakenet_enable`(audio_rec_handle_t handle, bool enable)

  Enable or suspend wake word detection.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Audio recorder handle

    - `enable`: true: enable wake word detection false: disable wake word detection

esp_err_t `audio_recorder_multinet_enable`(audio_rec_handle_t handle, bool enable)

  Enable or suspend speech command recognition.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Audio recorder handle

    - `enable`: true: enable speech command recognition false: disable speech command recognition

esp_err_t `audio_recorder_vad_check_enable`(audio_rec_handle_t handle, bool enable)

  Enable or suspend voice duration check.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Audio recorder handle

    - `enable`: true: enable voice duration check false: disable voice duration check

int `audio_recorder_data_read`(audio_rec_handle_t handle, void *buffer, int length, TickType_t ticks)

  Read data from audio recorder.

  Return

    Length of data actually read ESP_ERR_INVALID_ARG

  Parameters

    - `handle`: Audio recorder handle

    - `buffer`: Buffer to save data

    - `length`: Size of buffer

    - `ticks`: Timeout for reading

esp_err_t `audio_recorder_destroy`(audio_rec_handle_t handle)

  Destroy audio recorder and recycle all resource.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Audio recorder handle

bool `audio_recorder_get_wakeup_state`(audio_rec_handle_t handle)

  Get the wake up state of audio recorder.

  Return

    true false

  Parameters

    - `handle`: Audio recorder handle

###### Structures

struct `audio_rec_evt_t`

  Recorder event.

  Public Types

  enum [anonymous]

    Audio recorder event type.

    Values:

    `AUDIO_REC_WAKEUP_START` = -100

      Wakeup start

    `AUDIO_REC_WAKEUP_END`

      Wakeup stop

    `AUDIO_REC_VAD_START`

      Vad start

    `AUDIO_REC_VAD_END`

      Vad stop

    `AUDIO_REC_COMMAND_DECT` = 0

      Form 0 is the id of the voice commands detected by Multinet

  Public Members

  audio_rec_evt_t::[anonymous] `type`

    Audio recorder event type.

    Event type

  void *`event_data`

    Event data: For `AUDIO_REC_WAKEUP_START`, event data is `recorder_sr_wakeup_result_t` For `AUDIO_REC_COMMAND_DECT` or higher, event data is `recorder_sr_mn_result_t` For other events, event data is NULL

  size_t `data_len`

    Length of event data

struct `audio_rec_cfg_t`

  Audio recorder configuration.

  Public Members

  int `pinned_core`

    Audio recorder task pinned to core

  int `task_prio`

    Audio recorder task priority

  int `task_size`

    Audio recorder task stack size

  rec_event_cb_t `event_cb`

    Event callback function, event type as audio_rec_evt_t shown above

  void *`user_data`

    Pointer to user data (optional)

  recorder_data_read_t `read`

    Data callback function used feed data to audio recorder

  void *`sr_handle`

    SR handle

  recorder_sr_iface_t *`sr_iface`

    SR interface

  int `wakeup_time`

    Unit:ms. The duration that the wakeup state remains when VAD is not triggered

  int `vad_start`

    Unit:ms. Consecutive speech frame will be judged to vad start

  int `vad_off`

    Unit:ms. When the silence time exceeds this value, it is determined as AUDIO_REC_VAD_END state

  int `wakeup_end`

    Unit:ms. When the silence time after AUDIO_REC_VAD_END state exceeds this value, it is determined as AUDIO_REC_WAKEUP_END

  void *`encoder_handle`

    Encoder handle

  recorder_encoder_iface_t *`encoder_iface`

    Encoder interface

###### Macros

`AUDIO_REC_DEF_TASK_SZ`

  Stack size of recorder task

`AUDIO_REC_DEF_TASK_PRIO`

  Priority of recoder task

`AUDIO_REC_DEF_TASK_CORE`

  Pinned to core

`AUDIO_REC_DEF_WAKEUP_TM`

  Default wake up time (ms)

`AUDIO_REC_DEF_WAKEEND_TM`

  Duration after vad off (ms)

`AUDIO_REC_VAD_START_SPEECH_MS`

  Consecutive speech frame will be judged to vad start (ms)

`AUDIO_REC_DEF_VAD_OFF_TM`

  Default vad off time (ms)

`AUDIO_RECORDER_DEFAULT_CFG`()

###### Type Definitions

typedef esp_err_t (*`rec_event_cb_t`)(audio_rec_evt_t *event, void *user_data)

  Event Notification.

typedef struct __audio_recorder *`audio_rec_handle_t`

  Audio recorder handle.

###### Header File

- audio_recorder/include/recorder_sr.h

###### Functions

recorder_sr_handle_t `recorder_sr_create`(recorder_sr_cfg_t *cfg, recorder_sr_iface_t **iface)

  Initialize sr processor, and the sr is disabled as default.

  Return

    NULL failed Others SR handle

  Parameters

    - `cfg`: Configuration of sr

    - `iface`: User interface provide by recorder sr

esp_err_t `recorder_sr_destroy`(recorder_sr_handle_t handle)

  Destroy SR processor and recycle all resource.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: SR processor handle

esp_err_t `recorder_sr_reset_speech_cmd`(recorder_sr_handle_t handle, char *command_str, char *err_phrase_id)

  Reset the speech commands.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: SR processor handle

    - `command_str`: String of the commands. more details on `#2reset-api-on-the-fly`

    - `err_phrase_id`: error string output

###### Structures

struct `recorder_sr_cfg_t`

  SR processor configuration.

  Note

    Since the detection of command words requires a clear starting point, the moment the wake word is detected is taken as the default start of detection. Therefore, if the wake word detection is disabled, the detection will use the `vad_state` detected by `esp-sr` as the start of detection. However, due to the fluctuation of this `vad_state`, the effectiveness of command word detection will be limited.

  Public Members

  afe_config_t `afe_cfg`

    Configuration of AFE

  int8_t `input_order`[`DAT_CH_MAX`]

    Channel order of the input data

  bool `multinet_init`

    Enable of speech command recognition

  int `feed_task_core`

    Core id of feed task

  int `feed_task_prio`

    Priority of feed task

  int `feed_task_stack`

    Stack size of feed task

  int `fetch_task_core`

    Core id of fetch task

  int `fetch_task_prio`

    Priority of fetch task

  int `fetch_task_stack`

    Stack size of fetch task

  int `rb_size`

    Ringbuffer size of recorder sr

  char *`partition_label`

    Partition label which stored the model data

  char *`mn_language`

    Command language for multinet to load

  char *`wn_wakeword`

    Wake Word for WakeNet to load. This is useful when multiple Wake Words are selected in sdkconfig. Setting this to NULL will use the first found model.

###### Macros

`FEED_TASK_STACK_SZ`

`FETCH_TASK_STACK_SZ`

`FEED_TASK_PRIO`

`FETCH_TASK_PRIO`

`FEED_TASK_PINNED_CORE`

`FETCH_TASK_PINNED_CORE`

`SR_OUTPUT_RB_SIZE`

`INPUT_ORDER_DEFAULT`()

`DEFAULT_RECORDER_SR_CFG`()

###### Type Definitions

typedef void *`recorder_sr_handle_t`

  SR processor handle.

###### Header File

- audio_recorder/include/recorder_encoder.h

###### Functions

recorder_encoder_handle_t `recorder_encoder_create`(recorder_encoder_cfg_t *cfg, recorder_encoder_iface_t **iface)

  Initialize encoder processor, and the encoder is disabled as default.

  Return

    NULL failed Others encoder handle

  Parameters

    - `cfg`: Configuration of encoder

    - `iface`: User interface provide by recorder encoder

esp_err_t `recorder_encoder_destroy`(recorder_encoder_handle_t handle)

  Destroy encoder processor and recycle all resource.

  Return

    ESP_OK ESP_FAIL

  Parameters

    - `handle`: Encoder processor handle

###### Structures

struct `recorder_encoder_cfg_t`

  recorder encoder configuration parameters

  Public Members

  audio_element_handle_t `resample`

    Handle of resample

  audio_element_handle_t `encoder`

    Handle of encoder

###### Type Definitions

typedef void *`recorder_encoder_handle_t`

  encoder handle

### Peripherals

There are several peripherals available in the ESP-ADF, ranging from buttons and LEDs to SD Card or Wi-Fi. The peripherals are implemented using common API that is then expanded with peripheral specific functionality. The following description covers common functionality.

#### ESP Peripherals

This library simplifies the management of peripherals, by pooling and monitoring in a single task, adding basic functions to send and receive events. And it also provides APIs to easily integrate new peripherals.

Note

Note that if you do not intend to integrate new peripherals into esp_peripherals, you are only interested in simple api `esp_periph_init`, `esp_periph_start`, `esp_periph_stop` and `esp_periph_destroy`. If you want to integrate new peripherals, please refer to Periph Button source code

##### Examples

Please refer to player/pipeline_http_mp3/main/play_http_mp3_example.c.

##### API Reference

###### Header File

- esp_peripherals/include/esp_peripherals.h

###### Functions

esp_periph_set_handle_t `esp_periph_set_init`(esp_periph_config_t *config)

  Initialize esp_peripheral sets, create empty peripherals list. Call this function before starting any peripherals (with `esp_periph_start`). This call will initialize the data needed for esp_peripherals to work, but does not actually create the task. The `event_handle` is optional if you want to receive events from this callback function. The esp_peripherals task will send all events out to event_iface, can be listen by event_iface by `esp_periph_get_event_iface`. The `user_context` will sent `esp_periph_event_handle_t` as *context parameter.

  Return

    The peripheral sets instance

  Parameters

    - `[in] config`: The configurations

esp_err_t `esp_periph_set_destroy`(esp_periph_set_handle_t periph_set_handle)

  This function will stop and kill the monitor task, calling all destroy callback functions of the peripheral (so you do not need to destroy the peripheral object manually). It will also remove all memory allocated to the peripherals list, so you need to call the `esp_periph_set_init` function again if you want to use it.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

esp_err_t `esp_periph_set_stop_all`(esp_periph_set_handle_t periph_set_handle)

  Stop monitoring all peripherals, the peripheral state is still kept. This funciton only temporary disables the peripheral.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

esp_periph_handle_t `esp_periph_set_get_by_id`(esp_periph_set_handle_t periph_set_handle, int periph_id)

  Get the peripheral handle by Peripheral ID.

  Return

    The esp_periph_handle_t

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

    - `[in] periph_id`: as esp_periph_id_t, or any ID you use when calling `esp_periph_create`

audio_event_iface_handle_t `esp_periph_set_get_event_iface`(esp_periph_set_handle_t periph_set_handle)

  Return the event_iface used by this esp_peripherals.

  Return

    The audio event iface handle

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

esp_err_t `esp_periph_set_register_callback`(esp_periph_set_handle_t periph_set_handle, esp_periph_event_handle_t cb, void *user_context)

  Register peripheral sets event callback function.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

    - `cb`: The event handle callback function

    - `user_context`: The user context pointer

QueueHandle_t `esp_periph_set_get_queue`(esp_periph_set_handle_t periph_set_handle)

  Peripheral is using event_iface to control the event, all events are send out to event_iface queue. This function will be useful in case we want to read events directly from the event_iface queue.

  Return

    The queue handle

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

esp_err_t `esp_periph_set_list_init`(esp_periph_set_handle_t periph_set_handle)

  Call this function to initialize all the listed peripherals.

  Note

    Work with no task peripheral set only

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

esp_err_t `esp_periph_set_list_run`(esp_periph_set_handle_t periph_set_handle, audio_event_iface_msg_t msg)

  Call this function to run all the listed peripherals.

  Note

    Work with no task peripheral set only

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

    - `msg`: The audio_event_iface_msg_t handle message

esp_err_t `esp_periph_set_list_destroy`(esp_periph_set_handle_t periph_set_handle)

  Call this function to destroy all the listed peripherals.

  Note

    Work with no task peripheral set only

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

esp_err_t `esp_periph_remove_from_set`(esp_periph_set_handle_t periph_set_handle, esp_periph_handle_t periph)

  Call this function to remove periph from periph_set.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

    - `periph`: The esp_periph_handle_t instance

esp_err_t `esp_periph_alloc_periph_id`(esp_periph_set_handle_t periph_set_handle, int *periph_id)

  Allocated a peripheral ID from the periph_set.

  Note

    This function can apply for a peripheral ID to realize a customized peripheral module. The requested peripheral ID will not be included in `esp_periph_id_t`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph_set_handle`: The esp_periph_set_handle_t instance

    - `[out] periph_id`: The peripheral identifier

esp_err_t `esp_periph_set_change_waiting_time`(esp_periph_set_handle_t periph_set_handle, int time_ms)

  Call this function to change periph_set waiting time.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph_set_handle`: The esp_periph_set_handle_t instance

    - `time_ms`: The waiting time

esp_periph_handle_t `esp_periph_create`(int periph_id, const char *tag)

  Call this function to initialize a new peripheral.

  Return

    The peripheral handle

  Parameters

    - `[in] periph_id`: The periph identifier

    - `[in] tag`: The tag name, we named it easy to get in debug logs

esp_err_t `esp_periph_set_function`(esp_periph_handle_t periph, esp_periph_func init, esp_periph_run_func run, esp_periph_func destroy)

  Each peripheral has a cycle of sequential operations from initialization, execution of commands to destroying the peripheral. These operations are represented by functions passed as call parameters to this function.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

    - `[in] init`: The initialize

    - `[in] run`: The run

    - `[in] destroy`: The destroy

esp_err_t `esp_periph_start`(esp_periph_set_handle_t periph_set_handle, esp_periph_handle_t periph)

  Add the peripheral to peripherals list, enable and start monitor task (if task stack size > 0)

  Note

    This peripheral must be first created by calling `esp_periph_create`

  Return

    - ESP_OK on success

    - ESP_FAIL when any errors

  Parameters

    - `[in] periph_set_handle`: The esp_periph_set_handle_t instance

    - `[in] periph`: The peripheral instance

esp_err_t `esp_periph_stop`(esp_periph_handle_t periph)

  Stop monitoring the peripheral, the peripheral state is still kept. This funciton only temporary disables the peripheral.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

esp_err_t `esp_periph_send_cmd`(esp_periph_handle_t periph, int cmd, void *data, int data_len)

  When this function is called, the command is passed to the event_iface command queue, and the `esp_periph_run_func` of this peripheral will be executed in the main peripheral task. This function can be called from any task, basically it only sends a queue to the main peripheral task.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

    - `[in] cmd`: The command

    - `data`: The data

    - `[in] data_len`: The data length

esp_err_t `esp_periph_send_cmd_from_isr`(esp_periph_handle_t periph, int cmd, void *data, int data_len)

  Similar to `esp_periph_send_cmd`, but it can be called in the hardware interrupt handle.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

    - `[in] cmd`: The command

    - `data`: The data

    - `[in] data_len`: The data length

esp_err_t `esp_periph_send_event`(esp_periph_handle_t periph, int event_id, void *data, int data_len)

  In addition to sending an event via event_iface, this function will dispatch the `event_handle` callback if the event_handle callback is provided at `esp_periph_init`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The peripheral

    - `[in] event_id`: The event identifier

    - `data`: The data

    - `[in] data_len`: The data length

esp_err_t `esp_periph_start_timer`(esp_periph_handle_t periph, TickType_t interval_tick, timer_callback callback)

  Each peripheral can initialize a timer, which is by default NULL. When this function is called, the timer for the peripheral is created and it invokes the callback function every interval tick.

  Note

    - You do not need to stop or destroy the timer, when the `esp_periph_destroy` function is called, it will stop and destroy all

    - This timer using FreeRTOS Timer, with autoreload = true

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The peripheral

    - `[in] interval_tick`: The interval tick

    - `[in] callback`: The callback

esp_err_t `esp_periph_stop_timer`(esp_periph_handle_t periph)

  Stop peripheral timer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The peripheral

esp_err_t `esp_periph_set_data`(esp_periph_handle_t periph, void *data)

  Set the user data.

  Note

    Make sure the `data` lifetime is sufficient, this function does not copy all data, it only stores the data pointer

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The peripheral

    - `data`: The data

void *`esp_periph_get_data`(esp_periph_handle_t periph)

  Get the user data stored in the peripheral.

  Return

    Peripheral data pointer

  Parameters

    - `[in] periph`: The peripheral

esp_periph_state_t `esp_periph_get_state`(esp_periph_handle_t periph)

  Get the current state of peripheral.

  Return

    The peripharal working state

  Parameters

    - `[in] periph`: The handle of peripheral

esp_periph_id_t `esp_periph_get_id`(esp_periph_handle_t periph)

  Get Peripheral identifier.

  Return

    The peripheral identifier

  Parameters

    - `[in] periph`: The peripheral

esp_err_t `esp_periph_set_id`(esp_periph_handle_t periph, esp_periph_id_t periph_id)

  Set Peripheral identifier.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The peripheral

    - `[in] periph_id`: The peripheral identifier

esp_err_t `esp_periph_init`(esp_periph_handle_t periph)

  Call this to execute `init` function of peripheral instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph`: The peripheral handle

esp_err_t `esp_periph_run`(esp_periph_handle_t periph)

  Call this to execute `run` function of peripheral instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph`: The peripheral handle

esp_err_t `esp_periph_destroy`(esp_periph_handle_t periph)

  Call this to execute `destroy` function of peripheral instance.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph`: The peripheral handle

esp_err_t `esp_periph_register_on_events`(esp_periph_handle_t periph, esp_periph_event_t *evts)

  Rigster peripheral on event handle.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `periph`: The peripheral handle

    - `evts`: The esp_periph_event_t handle

###### Structures

struct `esp_periph_config_t`

  Common peripherals configurations.

  Public Members

  int `task_stack`

    >0 Service task stack size; =0 without task created

  int `task_prio`

    Service task priority (based on freeRTOS priority)

  int `task_core`

    Service task running in core (0 or 1)

  bool `extern_stack`

    Service task stack allocate on extern ram

struct `esp_periph_event`

  peripheral events

  Public Members

  void *`user_ctx`

    peripheral context data

  esp_periph_event_handle_t `cb`

    peripheral callback function

  audio_event_iface_handle_t `iface`

    peripheral event

###### Macros

`DEFAULT_ESP_PERIPH_STACK_SIZE`

`DEFAULT_ESP_PERIPH_TASK_PRIO`

`DEFAULT_ESP_PERIPH_TASK_CORE`

`DEFAULT_ESP_PERIPH_SET_CONFIG`()

`periph_tick_get`

###### Type Definitions

typedef struct esp_periph_sets *`esp_periph_set_handle_t`

typedef struct esp_periph *`esp_periph_handle_t`

typedef esp_err_t (*`esp_periph_func`)(esp_periph_handle_t periph)

typedef esp_err_t (*`esp_periph_run_func`)(esp_periph_handle_t periph, audio_event_iface_msg_t *msg)

typedef esp_err_t (*`esp_periph_event_handle_t`)(audio_event_iface_msg_t *event, void *context)

typedef void (*`timer_callback`)(xTimerHandle tmr)

typedef struct esp_periph_event `esp_periph_event_t`

  peripheral events

###### Enumerations

enum `esp_periph_id_t`

  Peripheral Identify, this must be unique for each peripheral added to the peripherals list.

  Values:

  `PERIPH_ID_BUTTON` = AUDIO_ELEMENT_TYPE_PERIPH + 1
  `PERIPH_ID_TOUCH` = AUDIO_ELEMENT_TYPE_PERIPH + 2
  `PERIPH_ID_SDCARD` = AUDIO_ELEMENT_TYPE_PERIPH + 3
  `PERIPH_ID_WIFI` = AUDIO_ELEMENT_TYPE_PERIPH + 4
  `PERIPH_ID_FLASH` = AUDIO_ELEMENT_TYPE_PERIPH + 5
  `PERIPH_ID_AUXIN` = AUDIO_ELEMENT_TYPE_PERIPH + 6
  `PERIPH_ID_ADC` = AUDIO_ELEMENT_TYPE_PERIPH + 7
  `PERIPH_ID_CONSOLE` = AUDIO_ELEMENT_TYPE_PERIPH + 8
  `PERIPH_ID_BLUETOOTH` = AUDIO_ELEMENT_TYPE_PERIPH + 9
  `PERIPH_ID_LED` = AUDIO_ELEMENT_TYPE_PERIPH + 10
  `PERIPH_ID_SPIFFS` = AUDIO_ELEMENT_TYPE_PERIPH + 11
  `PERIPH_ID_ADC_BTN` = AUDIO_ELEMENT_TYPE_PERIPH + 12
  `PERIPH_ID_IS31FL3216` = AUDIO_ELEMENT_TYPE_PERIPH + 13
  `PERIPH_ID_GPIO_ISR` = AUDIO_ELEMENT_TYPE_PERIPH + 14
  `PERIPH_ID_WS2812` = AUDIO_ELEMENT_TYPE_PERIPH + 15
  `PERIPH_ID_AW2013` = AUDIO_ELEMENT_TYPE_PERIPH + 16
  `PERIPH_ID_LCD` = AUDIO_ELEMENT_TYPE_PERIPH + 17
  `PERIPH_ID_CUSTOM_BASE` = AUDIO_ELEMENT_TYPE_PERIPH + 18

enum `esp_periph_state_t`

  Peripheral working state.

  Values:

  `PERIPH_STATE_NULL`
  `PERIPH_STATE_INIT`
  `PERIPH_STATE_RUNNING`
  `PERIPH_STATE_PAUSE`
  `PERIPH_STATE_STOPPING`
  `PERIPH_STATE_ERROR`
  `PERIPH_STATE_STATUS_MAX`

The peripheral specific functionality is available by calling dedicated functions described below. Some peripherals are available on both ESP32-LyraT and ESP32-LyraTD-MSC development boards, some on a specific board only. The following table provides all implemented peripherals broken down by development board.

#### Wi-Fi Peripheral

The Wi-Fi Peripheral is used to configure Wi-Fi connections, provide APIs to control Wi-Fi connection configuration, as well as monitor the status of Wi-Fi networks.

##### Application Example

Implementation of this API is demonstrated in player/pipeline_http_mp3 example.

##### API Reference

###### Header File

- esp_peripherals/include/periph_wifi.h

###### Functions

esp_periph_handle_t `periph_wifi_init`(periph_wifi_cfg_t *config)

  Create the wifi peripheral handle for esp_peripherals.

  Note

    The handle was created by this function automatically destroy when `esp_periph_destroy` is called

  Return

    The esp peripheral handle

  Parameters

    - `config`: The configuration

esp_err_t `periph_wifi_wait_for_connected`(esp_periph_handle_t periph, TickType_t tick_to_wait)

  This function will block current thread (in `tick_to_wait` tick) and wait until ESP32 connected to the Wi-Fi network, and got ip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

    - `[in] tick_to_wait`: The tick to wait

periph_wifi_state_t `periph_wifi_is_connected`(esp_periph_handle_t periph)

  Check the Wi-Fi connection status.

  Return

    Wi-Fi network status

  Parameters

    - `[in] periph`: The periph

esp_err_t `esp_wifi_set_listen_interval`(esp_periph_handle_t periph, int interval)

  Set Wi-Fi listen interval for ESP32 station to receive beacon.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The wifi periph

    - `[in] interval`: listen interval. units: AP beacon intervals(see BcnInt, default: 100ms)

esp_err_t `periph_wifi_config_start`(esp_periph_handle_t periph, periph_wifi_config_mode_t mode)

  Start Wi-Fi network setup in `mode`

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

    - `[in] mode`: The mode

esp_err_t `periph_wifi_config_wait_done`(esp_periph_handle_t periph, TickType_t tick_to_wait)

  Wait for Wi-Fi setup done.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

    - `[in] tick_to_wait`: The tick to wait

###### Structures

struct `periph_wpa2_enterprise_cfg_t`

  The WPA2 enterprise peripheral configuration.

  Public Members

  bool `diasble_wpa2_e`

    Disable wpa2 enterprise

  int `eap_method`

    TLS: 0, PEAP: 1, TTLS: 2

  char *`ca_pem_start`

    binary wpa2 ca pem start

  char *`ca_pem_end`

    binary wpa2 ca pem end

  char *`wpa2_e_cert_start`

    binary wpa2 cert start

  char *`wpa2_e_cert_end`

    binary wpa2 cert end

  char *`wpa2_e_key_start`

    binary wpa2 key start

  char *`wpa2_e_key_end`

    binary wpa2 key end

  const char *`eap_id`

    Identity in phase 1 of EAP procedure

  const char *`eap_username`

    Username for EAP method (PEAP and TTLS)

  const char *`eap_password`

    Password for EAP method (PEAP and TTLS)

struct `periph_wifi_cfg_t`

  The Wi-Fi peripheral configuration.

  Public Members

  bool `disable_auto_reconnect`

    Disable Wi-Fi auto reconnect

  int `reconnect_timeout_ms`

    The reconnect timeout after disconnected from Wi-Fi network

  wifi_config_t `wifi_config`

    Wifi configure

  periph_wpa2_enterprise_cfg_t `wpa2_e_cfg`

    wpa2 enterprise config

###### Enumerations

enum `periph_wifi_state_t`

  Peripheral Wi-Fi event id.

  Values:

  `PERIPH_WIFI_UNCHANGE` = 0
  `PERIPH_WIFI_CONNECTING`
  `PERIPH_WIFI_CONNECTED`
  `PERIPH_WIFI_DISCONNECTED`
  `PERIPH_WIFI_SETTING`
  `PERIPH_WIFI_CONFIG_DONE`
  `PERIPH_WIFI_CONFIG_ERROR`
  `PERIPH_WIFI_ERROR`

enum `periph_wifi_config_mode_t`

  Wi-Fi setup mode type.

  Values:

  `WIFI_CONFIG_ESPTOUCH`

    Using smartconfig with ESPTOUCH protocol

  `WIFI_CONFIG_AIRKISS`

    Using smartconfig with AIRKISS protocol

  `WIFI_CONFIG_ESPTOUCH_AIRKISS`

    Using smartconfig with ESPTOUCH_AIRKISS protocol

  `WIFI_CONFIG_WPS`

    Using WPS (not support)

  `WIFI_CONFIG_BLUEFI`

    Using BLUEFI

  `WIFI_CONFIG_WEB`

    Using HTTP Server (not support)

#### SD Card Peripheral

If your board has a SD card connected, use this API to initialize, mount and unmount the card, see functions `periph_sdcard_init()`, `periph_sdcard_mount()` and `periph_sdcard_unmount()`. The data reading / writing is implemented in a separate API described in FatFs Stream.

##### Application Examples

Implementation of this API is demonstrated in couple of examples:

- player/pipeline_play_sdcard_music

- player/pipeline_sdcard_mp3_control

- recorder/pipeline_recording_to_sdcard

- recorder/pipeline_wav_amr_sdcard

##### API Reference

###### Header File

- esp_peripherals/include/periph_sdcard.h

###### Functions

esp_periph_handle_t `periph_sdcard_init`(periph_sdcard_cfg_t *sdcard_config)

  Create the sdcard peripheral handle for esp_peripherals.

  Note

    The handle was created by this function automatically destroy when `esp_periph_destroy` is called

  Return

    The esp peripheral handle

  Parameters

    - `sdcard_config`: The sdcard configuration

bool `periph_sdcard_is_mounted`(esp_periph_handle_t periph)

  Check the sdcard is mounted or not.

  Return

    SDCARD mounted state

  Parameters

    - `[in] periph`: The periph

###### Structures

struct `periph_sdcard_cfg_t`

  The SD Card Peripheral configuration.

  Public Members

  int `card_detect_pin`

    Card detect gpio number

  const char *`root`

    Base path for vfs

  periph_sdcard_mode_t `mode`

    card mode

###### Enumerations

enum `periph_sdcard_event_id_t`

  Peripheral sdcard event id.

  Values:

  `SDCARD_STATUS_UNKNOWN`

    No event

  `SDCARD_STATUS_CARD_DETECT_CHANGE`

    Detect changes in the card_detect pin

  `SDCARD_STATUS_MOUNTED`

    SDCARD mounted successfully

  `SDCARD_STATUS_UNMOUNTED`

    SDCARD unmounted successfully

  `SDCARD_STATUS_MOUNT_ERROR`

    SDCARD mount error

  `SDCARD_STATUS_UNMOUNT_ERROR`

    SDCARD unmount error

enum `periph_sdcard_mode_t`

  SD card mode, SPI, 1-line SD mode, 4-line SD mode.

  Values:

  `SD_MODE_SPI` = 0x0

    sd_card SPI

  `SD_MODE_1_LINE` = 0x1

    sd_card 1-line SD mode

  `SD_MODE_4_LINE` = 0x4

    sd_card 4-line SD mode

  `SD_MODE_8_LINE` = 0x8

    sd_card 8-line SD mode

  `SD_MODE_MAX`

#### Spiffs Peripheral

Use this API to initialize, mount and unmount spiffs partition, see functions `periph_spiffs_init()`, `periph_spiffs_mount()` and `periph_spiffs_unmount()`. The data reading / writing is implemented in a separate API described in SPIFFS Stream.

##### Application Example

Implementation of this API is demonstrated in audio_processing/pipeline_spiffs_amr_resample example.

##### API Reference

###### Header File

- esp_peripherals/include/periph_spiffs.h

###### Functions

esp_periph_handle_t `periph_spiffs_init`(periph_spiffs_cfg_t *spiffs_config)

  Create the spiffs peripheral handle for esp_peripherals.

  Note

    The handle created by this function will be automatically destroyed when `esp_periph_destroy` is called

  Return

    The esp peripheral handle

  Parameters

    - `spiffs_config`: The spiffs configuration

bool `periph_spiffs_is_mounted`(esp_periph_handle_t periph)

  Check if the SPIFFS is mounted or not.

  Return

    SPIFFS mounted state

  Parameters

    - `[in] periph`: The periph

###### Structures

struct `periph_spiffs_cfg_t`

  The SPIFFS Peripheral configuration.

  Public Members

  const char *`root`

    Base path for vfs

  const char *`partition_label`

    Optional, label of SPIFFS partition to use. If set to NULL, first partition with subtype=spiffs will be used.

  size_t `max_files`

    Maximum number of files that could be open at the same time.

  bool `format_if_mount_failed`

    If true, it will format the file system if it fails to mount.

###### Enumerations

enum `periph_spiffs_event_id_t`

  Peripheral spiffs event id.

  Values:

  `SPIFFS_STATUS_UNKNOWN`

    No event

  `SPIFFS_STATUS_MOUNTED`

    SPIFFS mounted successfully

  `SPIFFS_STATUS_UNMOUNTED`

    SPIFFS unmounted successfully

  `SPIFFS_STATUS_MOUNT_ERROR`

    SPIFFS mount error

  `SPIFFS_STATUS_UNMOUNT_ERROR`

    SPIFFS unmount error

#### Console Peripheral

Console Peripheral is used to control the Audio application from the terminal screen. It provides 2 ways do execute command, one sends an event to esp_peripherals (for a command without parameters), another calls a callback function (need parameters). If there is a callback function, no event will be sent.

Please make sure that the lifetime of `periph_console_cmd_t` must be ensured during console operation, `periph_console_init()` only reference, does not make a copy.

##### Code example

Please refer to cli/main/console_example.c.

##### API Reference

###### Header File

- esp_peripherals/include/periph_console.h

###### Functions

esp_periph_handle_t `periph_console_init`(periph_console_cfg_t *config)

  Initialize Console Peripheral.

  Return

    The esp peripheral handle

  Parameters

    - `config`: The configuration

###### Structures

struct `periph_console_cmd_t`

  Command structure.

  Public Members

  const char *`cmd`

    Name of command, must be unique

  int `id`

    Command ID will be sent together when the command is matched

  const char *`help`

    Explanation of the command

  console_cmd_callback_t `func`

    Function callback for the command

struct `periph_console_cfg_t`

  Console Peripheral configuration.

  Public Members

  int `command_num`

    Total number of commands

  const periph_console_cmd_t *`commands`

    Pointer to array of commands

  int `task_stack`

    Console task stack, using default if the value is zero

  int `task_prio`

    Console task priority (based on freeRTOS priority), using default if the value is zero

  int `buffer_size`

    Size of console input buffer

  const char *`prompt_string`

    Console prompt string, using default CONSOLE_PROMPT_STRING if the pointer is NULL

###### Macros

`CONSOLE_DEFAULT_TASK_PRIO`

`CONSOLE_DEFAULT_TASK_STACK`

`CONSOLE_DEFAULT_BUFFER_SIZE`

`CONSOLE_DEFAULT_PROMPT_STRING`

###### Type Definitions

typedef esp_err_t (*`console_cmd_callback_t`)(esp_periph_handle_t periph, int argc, char *argv[])

#### Touch Peripheral

Initialize ESP32 touchpad peripheral and retrieve information from the touch sensors.

##### Application Example

Implementation of this API is demonstrated in get-started/play_mp3_control example.

##### API Reference

###### Header File

- esp_peripherals/include/periph_touch.h

###### Functions

esp_periph_handle_t `periph_touch_init`(periph_touch_cfg_t *config)

  Create the touch peripheral handle for esp_peripherals.

  Note

    The handle was created by this function automatically destroy when `esp_periph_destroy` is called

  Return

    The esp peripheral handle

  Parameters

    - `config`: The configuration

###### Structures

struct `periph_touch_cfg_t`

  The Touch peripheral configuration.

  Public Members

  int `touch_mask`

    Touch pad mask using for this Touch peripheral, ex: TOUCH_PAD_SEL0 | TOUCH_PAD_SEL1

  int `tap_threshold_percent`

    Tap threshold percent, Tap event will be determined if the percentage value is less than the non-touch value

  int `long_tap_time_ms`

    Long tap duration in milliseconds, default is 2000ms, PERIPH_TOUCH_LONG_TAP will be occurred if TAP and time hold longer than this value

###### Enumerations

enum `esp_touch_pad_sel_t`

  Touch pad selection.

  Values:

  `TOUCH_PAD_SEL0` = BIT(0)
  `TOUCH_PAD_SEL1` = BIT(1)
  `TOUCH_PAD_SEL2` = BIT(2)
  `TOUCH_PAD_SEL3` = BIT(3)
  `TOUCH_PAD_SEL4` = BIT(4)
  `TOUCH_PAD_SEL5` = BIT(5)
  `TOUCH_PAD_SEL6` = BIT(6)
  `TOUCH_PAD_SEL7` = BIT(7)
  `TOUCH_PAD_SEL8` = BIT(8)
  `TOUCH_PAD_SEL9` = BIT(9)

enum `periph_touch_event_id_t`

  Peripheral touch event id.

  Values:

  `PERIPH_TOUCH_UNCHANGE` = 0

    No event

  `PERIPH_TOUCH_TAP`

    When touch pad is tapped

  `PERIPH_TOUCH_RELEASE`

    When touch pad is released after tap

  `PERIPH_TOUCH_LONG_TAP`

    When touch pad is tapped and held after `long_tap_time_ms` time

  `PERIPH_TOUCH_LONG_RELEASE`

    When touch pad is released after long tap

#### Button Peripheral

To control application flow you may use buttons connected and read through the ESP32 GPIOs. This API provides functions to initialize specific GPIOs and obtain information on button events such as when it has been pressed, when released, when pressed for a long time and released after long press. To get information on a particular event, establish a callback function with `button_dev_add_tap_cb()` or `button_dev_add_press_cb()`.

##### Application Example

Implementation of this API is demonstrated in cloud_services/google_translate_device example.

##### API Reference

###### Header File

- esp_peripherals/include/periph_button.h

###### Functions

esp_periph_handle_t `periph_button_init`(periph_button_cfg_t *but_cfg)

  Create the button peripheral handle for esp_peripherals.

  Note

    The handle was created by this function automatically destroy when `esp_periph_destroy` is called

  Return

    The esp peripheral handle

  Parameters

    - `but_cfg`: The but configuration

###### Structures

struct `periph_button_cfg_t`

  The Button peripheral configuration.

  Public Members

  uint64_t `gpio_mask`

    GPIO Mask using for this Button peripheral, it is BIT(GPIO_NUM), ex: GPIO_SEL_36 | GPIO_SEL_36

  int `long_press_time_ms`

    Long press duration in milliseconds, default is 2000ms

###### Enumerations

enum `periph_button_event_id_t`

  Peripheral button event id.

  Values:

  `PERIPH_BUTTON_UNCHANGE` = 0

    No event

  `PERIPH_BUTTON_PRESSED`

    When button is pressed

  `PERIPH_BUTTON_RELEASE`

    When button is released

  `PERIPH_BUTTON_LONG_PRESSED`

    When button is pressed and kept for more than `long_press_time_ms`

  `PERIPH_BUTTON_LONG_RELEASE`

    When button is released and event PERIPH_BUTTON_LONG_PRESSED happened

#### LED Peripheral

Blink or fade a LED connected to a GPIO with configurable On and Off times.

##### Application Examples

Implementation of this API is demonstrated in couple of examples:

- /cloud_services/google_translate_device

- /dueros

##### API Reference

###### Header File

- esp_peripherals/include/periph_led.h

###### Functions

esp_periph_handle_t `periph_led_init`(periph_led_cfg_t *config)

  Create the LED peripheral handle for esp_peripherals.

  Note

    The handle was created by this function automatically destroy when `esp_periph_destroy` is called

  Return

    The esp peripheral handle

  Parameters

    - `config`: The configuration

esp_err_t `periph_led_blink`(esp_periph_handle_t periph, int gpio_num, int time_on_ms, int time_off_ms, bool fade, int loop, periph_led_idle_level_t level)

  Bink LED Peripheral, this function will automatically configure the gpio_num to control the LED, with `time_on_ms` as the time (in milliseconds) switch from OFF to ON (or ON if fade is disabled), and `time_off_ms` as the time (in milliseconds) switch from ON to OFF (or OFF if fade is disabled). When switching from ON -> OFF and vice versa, the loop decreases once, and will turn off the effect when the loop is 0. With a loop value less than 0, the LED effect will loop endlessly. PERIPH_LED_BLINK_FINISH events will be sent at each end of loop.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The LED periph

    - `[in] gpio_num`: The gpio number

    - `[in] time_on_ms`: The time on milliseconds

    - `[in] time_off_ms`: The time off milliseconds

    - `[in] fade`: Fading enabled

    - `[in] loop`: Loop

    - `[in] level`: idle level

esp_err_t `periph_led_stop`(esp_periph_handle_t periph, int gpio_num)

  Stop Blink the LED.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] periph`: The periph

    - `[in] gpio_num`: The gpio number

###### Structures

struct `periph_led_cfg_t`

  The LED peripheral configuration.

  Public Members

  ledc_mode_t `led_speed_mode`

    LEDC speed speed_mode, high-speed mode or low-speed mode

  ledc_timer_bit_t `led_duty_resolution`

    LEDC channel duty resolution

  ledc_timer_t `led_timer_num`

    Select the timer source of channel (0 - 3)

  uint32_t `led_freq_hz`

    LEDC timer frequency (Hz)

  int `gpio_num`

    Optional, < 0 invalid gpio number

###### Enumerations

enum `periph_led_event_id_t`

  Peripheral LED event id.

  Values:

  `PERIPH_LED_UNCHANGE` = 0

    No event

  `PERIPH_LED_BLINK_FINISH`

    When LED blink is finished

enum `periph_led_idle_level_t`

  Peripheral LED idle output level.

  Values:

  `PERIPH_LED_IDLE_LEVEL_LOW`

    Low level output

  `PERIPH_LED_IDLE_LEVEL_HIGH`

    High level output

#### ADC Button Peripheral

Read status of buttons connected to an ADC input using a resistor ladder. Configuration provides for more than a singe ADC input to read several sets of buttons. For an example hardware implementation please refer to schematic of ESP32-LyraTD-MSC V2.2 Upper Board (PDF).

##### Application Examples

Implementation of this API is demonstrated in the following example:

- checks/check_board_buttons

##### API Reference

###### Header File

- esp_peripherals/include/periph_adc_button.h

###### Functions

esp_periph_handle_t `periph_adc_button_init`(periph_adc_button_cfg_t *btn_cfg)

  Create the button peripheral handle for esp_peripherals.

  Note

    The handle created by this function is automatically destroyed when esp_periph_destroy is called.

  Return

    The esp peripheral handle.

  Parameters

    - `btn_cfg`: The button configuration.

###### Structures

struct `periph_adc_button_cfg_t`

  The configuration of ADC Button.

  Public Members

  adc_arr_t *`arr`

    An array with configuration of buttons

  int `arr_size`

    The array size

  adc_btn_task_cfg_t `task_cfg`

    Adc button task configuration

###### Macros

`ADC_BUTTON_STACK_SIZE`

`ADC_BUTTON_TASK_PRIORITY`

`ADC_BUTTON_TASK_CORE_ID`

`PERIPH_ADC_BUTTON_DEFAULT_CONFIG`()

`ADC_DEFAULT_ARR`()

  ESP32 ADC1 channels and GPIO table ADC1_CHANNEL_0 - GPIO36 ADC1_CHANNEL_1 - GPIO37 ADC1_CHANNEL_2 - GPIO38 ADC1_CHANNEL_3 - GPIO39 ADC1_CHANNEL_4 - GPIO32 ADC1_CHANNEL_5 - GPIO33 ADC1_CHANNEL_6 - GPIO34 ADC1_CHANNEL_7 - GPIO35

###### Enumerations

enum `periph_adc_button_event_id_t`

  Values:

  `PERIPH_ADC_BUTTON_IDLE` = 0
  `PERIPH_ADC_BUTTON_PRESSED`
  `PERIPH_ADC_BUTTON_RELEASE`
  `PERIPH_ADC_BUTTON_LONG_PRESSED`
  `PERIPH_ADC_BUTTON_LONG_RELEASE`

#### LED Controller Peripheral

This peripheral is applicable to IS31Fl3216 chip that is a light LED controller with an audio modulation mode. It can store data of 8 Frames with internal RAM to play small animations automatically. You can also use it to control a number of LEDs connected to GPIOs. If you want to use the IS31Fl3216, see functions `periph_is31fl3216_init()`, `periph_is31fl3216_set_blink_pattern()`, `periph_is31fl3216_set_duty()`, `periph_is31fl3216_set_state()`.

##### Application Examples

Implementation of this API is demonstrated in checks/check_display_led example.

##### API Reference

###### Header File

- esp_peripherals/include/periph_is31fl3216.h

###### Functions

esp_periph_handle_t `periph_is31fl3216_init`(periph_is31fl3216_cfg_t *is31fl3216_config)

  Initializate the is31fl3216.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `is31fl3216_config`:

esp_err_t `periph_is31fl3216_set_state`(esp_periph_handle_t periph, periph_is31fl3216_state_t state)

  Set the state of all the channels.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `state`: The state of all channels

esp_err_t `periph_is31fl3216_set_blink_pattern`(esp_periph_handle_t periph, uint16_t blink_pattern)

  Set the current enable channels.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `blink_pattern`: The bit pattern of enabled channels

esp_err_t `periph_is31fl3216_set_duty`(esp_periph_handle_t periph, uint8_t index, uint8_t value)

  Set the duty of the channel.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `index`: The channel number

    - `value`: The value of the channel’s duty to be set

esp_err_t `periph_is31fl3216_set_duty_step`(esp_periph_handle_t periph, uint8_t step)

  Set the duty step of flash.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `step`: The step of flash

esp_err_t `periph_is31fl3216_set_interval`(esp_periph_handle_t periph, uint16_t interval_ms)

  Set the internval time.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `interval_ms`: Time of interval

esp_err_t `periph_is31fl3216_set_shift_mode`(esp_periph_handle_t periph, periph_is31_shift_mode_t mode)

  Set the shift mode.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `mode`: Mode of periph_is31_shift_mode_t

esp_err_t `periph_is31fl3216_set_light_on_num`(esp_periph_handle_t periph, uint16_t light_on_num, uint16_t max_light_num)

  Set the light on numbers.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `light_on_num`: Enabled led number

    - `max_light_num`: Maximum led number

esp_err_t `periph_is31fl3216_set_act_time`(esp_periph_handle_t periph, uint16_t act_ms)

  Set the action time.

  Return

    - ESP_OK Success

    - ESP_FAIL Fail

  Parameters

    - `periph`: The is31fl3216 handle

    - `act_ms`: Action time, unit is millisecond, 0 is infinite

###### Structures

struct `periph_is31fl3216_cfg_t`

  The configuration of is31fl3216.

  Public Members

  uint32_t `duty`[`IS31FL3216_CH_NUM`]

    An array of the is31fl3216’s duty

  uint16_t `is31fl3216_pattern`

    Current enable channel

  periph_is31fl3216_state_t `state`

    The state of all the channels

###### Macros

`IS31FL3216_CH_NUM`

`BLUE_LED_MAX_NUM`

###### Enumerations

enum `periph_is31fl3216_state_t`

  Values:

  `IS31FL3216_STATE_UNKNOWN`
  `IS31FL3216_STATE_OFF`
  `IS31FL3216_STATE_ON`
  `IS31FL3216_STATE_FLASH`
  `IS31FL3216_STATE_BY_AUDIO`
  `IS31FL3216_STATE_SHIFT`

enum `periph_is31_shift_mode_t`

  Values:

  `PERIPH_IS31_SHIFT_MODE_UNKNOWN`
  `PERIPH_IS31_SHIFT_MODE_ACC`

    accumulation mode

  `PERIPH_IS31_SHIFT_MODE_SINGLE`

Name of Peripheral | ESP32-LyraT | ESP32-LyraTD-MSC
--- | --- | ---
Wi-Fi |  |
SD Card |  |
Spiffs |  |
Console |  |
Touch |  |
Button |  |
LED |  |
ADC Button |  |
LED Controller |  |

### Abstraction Layer

#### Ring Buffer

Ringbuffer is designed in addition to use as a data buffer, also used to connect Audio Elements. Each Element that requests data from the Ringbuffer will block the task until the data is available. Or block the task when writing data and the Buffer is full. Of course, we can stop this block at any time.

Ring Buffer used in Audio Pipeline

##### Application Example

In most of ESP-ADF examples connecting of Elements with Ringbuffers is done “behind the scenes” by a function `audio_pipeline_link()`. To see this operation exposed check player/pipeline_sdcard_mp3_control example.

##### API Reference

###### Header File

- audio_pipeline/include/ringbuf.h

###### Functions

ringbuf_handle_t `rb_create`(int block_size, int n_blocks)

  Create ringbuffer with total size = block_size * n_blocks.

  Return

    ringbuf_handle_t

  Parameters

    - `[in] block_size`: Size of each block

    - `[in] n_blocks`: Number of blocks

esp_err_t `rb_destroy`(ringbuf_handle_t rb)

  Cleanup and free all memory created by ringbuf_handle_t.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

esp_err_t `rb_abort`(ringbuf_handle_t rb)

  Abort waiting until there is space for reading or writing of the ringbuffer.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

esp_err_t `rb_reset`(ringbuf_handle_t rb)

  Reset ringbuffer, clear all values as initial state.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

esp_err_t `rb_reset_is_done_write`(ringbuf_handle_t rb)

  Reset is_done_write flag.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

int `rb_bytes_available`(ringbuf_handle_t rb)

  Get total bytes available of Ringbuffer.

  Return

    total bytes available

  Parameters

    - `[in] rb`: The Ringbuffer handle

int `rb_bytes_filled`(ringbuf_handle_t rb)

  Get the number of bytes that have filled the ringbuffer.

  Return

    The number of bytes that have filled the ringbuffer

  Parameters

    - `[in] rb`: The Ringbuffer handle

int `rb_get_size`(ringbuf_handle_t rb)

  Get total size of Ringbuffer (in bytes)

  Return

    total size of Ringbuffer

  Parameters

    - `[in] rb`: The Ringbuffer handle

int `rb_read`(ringbuf_handle_t rb, char *buf, int len, TickType_t ticks_to_wait)

  Read from Ringbuffer to `buf` with len and wait `tick_to_wait` ticks until enough bytes to read if the ringbuffer bytes available is less than `len`. If `buf` argument provided is `NULL`, then ringbuffer do pseudo reads by simply advancing pointers.

  Return

    Number of bytes read

  Parameters

    - `[in] rb`: The Ringbuffer handle

    - `buf`: The buffer pointer to read out data

    - `[in] len`: The length request

    - `[in] ticks_to_wait`: The ticks to wait

int `rb_write`(ringbuf_handle_t rb, char *buf, int len, TickType_t ticks_to_wait)

  Write to Ringbuffer from `buf` with `len` and wait `tick_to_wait` ticks until enough space to write if the ringbuffer space available is less than `len`

  Return

    Number of bytes written

  Parameters

    - `[in] rb`: The Ringbuffer handle

    - `buf`: The buffer

    - `[in] len`: The length

    - `[in] ticks_to_wait`: The ticks to wait

esp_err_t `rb_done_write`(ringbuf_handle_t rb)

  Set status of writing to ringbuffer is done.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

esp_err_t `rb_unblock_reader`(ringbuf_handle_t rb)

  Unblock from rb_read.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

esp_err_t `rb_set_reader_holder`(ringbuf_handle_t rb, void *holder)

  Set the owner of the ‘rb_read’.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

    - `[in] holder`: The owner of the ‘rb_read’

esp_err_t `rb_get_reader_holder`(ringbuf_handle_t rb, void **holder)

  Get the owner of the ‘rb_read’.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

    - `[out] holder`: The owner of the ‘rb_read’

esp_err_t `rb_set_writer_holder`(ringbuf_handle_t rb, void *holder)

  Set the owner of the ‘rb_write’.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

    - `[in] holder`: The owner of the ‘rb_write’

esp_err_t `rb_get_writer_holder`(ringbuf_handle_t rb, void **holder)

  Get the owner of the ‘rb_write’.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[in] rb`: The Ringbuffer handle

    - `[out] holder`: The owner of the ‘rb_write’

###### Macros

`RB_OK`

`RB_FAIL`

`RB_DONE`

`RB_ABORT`

`RB_TIMEOUT`

###### Type Definitions

typedef struct ringbuf *`ringbuf_handle_t`

#### Audio HAL

Abstraction layer for audio board hardware, serves as an interface between the user application and the hardware driver for specific audio board like ESP32 LyraT.

The API provides data structures to configure sampling rates of ADC and DAC signal conversion, data bit widths, I2C stream parameters, and selection of signal channels connected to ADC and DAC. It also contains several specific functions to e.g. initialize the audio board, `audio_hal_init()`, control the volume, `audio_hal_get_volume()` and `audio_hal_set_volume()`.

##### API Reference

###### Header File

- audio_hal/include/audio_hal.h

###### Functions

audio_hal_handle_t `audio_hal_init`(audio_hal_codec_config_t *audio_hal_conf, audio_hal_func_t *audio_hal_func)

  Initialize media codec driver.

  Note

    If selected codec has already been installed, it’ll return the audio_hal handle.

  Return

    int, 0success, othersfail

  Parameters

    - `audio_hal_conf`: Configure structure audio_hal_config_t

    - `audio_hal_func`: Structure containing functions used to operate audio the codec chip

esp_err_t `audio_hal_deinit`(audio_hal_handle_t audio_hal)

  Uninitialize media codec driver.

  Return

    int, 0success, othersfail

  Parameters

    - `audio_hal`: reference function pointer for selected audio codec

esp_err_t `audio_hal_ctrl_codec`(audio_hal_handle_t audio_hal, audio_hal_codec_mode_t mode, audio_hal_ctrl_t audio_hal_ctrl)

  Start/stop codec driver.

  Return

    int, 0success, othersfail

  Parameters

    - `audio_hal`: reference function pointer for selected audio codec

    - `mode`: select media hal codec mode either encode/decode/or both to start from audio_hal_codec_mode_t

    - `audio_hal_ctrl`: select start stop state for specific mode

esp_err_t `audio_hal_codec_iface_config`(audio_hal_handle_t audio_hal, audio_hal_codec_mode_t mode, audio_hal_codec_i2s_iface_t *iface)

  Set codec I2S interface samples rate & bit width and format either I2S or PCM/DSP.

  Return

    - 0 Success

    - -1 Error

  Parameters

    - `audio_hal`: reference function pointer for selected audio codec

    - `mode`: select media hal codec mode either encode/decode/or both to start from audio_hal_codec_mode_t

    - `iface`: I2S sample rate (ex: 16000, 44100), I2S bit width (16, 24, 32),I2s format (I2S, PCM, DSP).

esp_err_t `audio_hal_set_mute`(audio_hal_handle_t audio_hal, bool mute)

  Set voice mute. Enables or disables DAC mute of a codec.

  Note

    `audio_hal_get_volume` will still give a non-zero number in mute state. It will be set to that number when speaker is unmuted.

  Return

    int, 0success, othersfail

  Parameters

    - `audio_hal`: reference function pointer for selected audio codec

    - `mute`: true/false. If true speaker will be muted and if false speaker will be unmuted.

esp_err_t `audio_hal_set_volume`(audio_hal_handle_t audio_hal, int volume)

  Set voice volume.

  Note

    if volume is 0, mute is enabled,range is 0-100.

  Return

    int, 0success, othersfail

  Parameters

    - `audio_hal`: reference function pointer for selected audio codec

    - `volume`: value of volume in percent(%)

esp_err_t `audio_hal_get_volume`(audio_hal_handle_t audio_hal, int *volume)

  get voice volume.

  Note

    if volume is 0, mute is enabled, range is 0-100.

  Return

    int, 0success, othersfail

  Parameters

    - `audio_hal`: reference function pointer for selected audio codec

    - `volume`: value of volume in percent returned(%)

esp_err_t `audio_hal_enable_pa`(audio_hal_handle_t audio_hal, bool enable)

  Enables or disables PA.

  Return

    int, 0success, othersfail

  Parameters

    - `audio_hal`: reference function pointer for selected audio codec

    - `enable`: true/false.

###### Structures

struct `audio_hal_codec_i2s_iface_t`

  I2s interface configuration for audio codec chip.

  Public Members

  audio_hal_iface_mode_t `mode`

    audio codec chip mode

  audio_hal_iface_format_t `fmt`

    I2S interface format

  audio_hal_iface_samples_t `samples`

    I2S interface samples per second

  audio_hal_iface_bits_t `bits`

    i2s interface number of bits per sample

struct `audio_hal_codec_config_t`

  Configure media hal for initialization of audio codec chip.

  Public Members

  audio_hal_adc_input_t `adc_input`

    set adc channel

  audio_hal_dac_output_t `dac_output`

    set dac channel

  audio_hal_codec_mode_t `codec_mode`

    select codec mode: adc, dac or both

  audio_hal_codec_i2s_iface_t `i2s_iface`

    set I2S interface configuration

struct `audio_hal`

  Configuration of functions and variables used to operate audio codec chip.

  Public Members

  esp_err_t (*`audio_codec_initialize`)(audio_hal_codec_config_t *codec_cfg)

    initialize codec

  esp_err_t (*`audio_codec_deinitialize`)(void)

    deinitialize codec

  esp_err_t (*`audio_codec_ctrl`)(audio_hal_codec_mode_t mode, audio_hal_ctrl_t ctrl_state)

    control codec mode and state

  esp_err_t (*`audio_codec_config_iface`)(audio_hal_codec_mode_t mode, audio_hal_codec_i2s_iface_t *iface)

    configure i2s interface

  esp_err_t (*`audio_codec_set_mute`)(bool mute)

    set codec mute

  esp_err_t (*`audio_codec_set_volume`)(int volume)

    set codec volume

  esp_err_t (*`audio_codec_get_volume`)(int *volume)

    get codec volume

  esp_err_t (*`audio_codec_enable_pa`)(bool enable)

    enable pa

  xSemaphoreHandle `audio_hal_lock`

    semaphore of codec

  void *`handle`

    handle of audio codec

###### Macros

`AUDIO_HAL_VOL_DEFAULT`

###### Type Definitions

typedef struct audio_hal *`audio_hal_handle_t`

typedef struct audio_hal `audio_hal_func_t`

  Configuration of functions and variables used to operate audio codec chip.

###### Enumerations

enum `audio_hal_codec_mode_t`

  Select media hal codec mode.

  Values:

  `AUDIO_HAL_CODEC_MODE_ENCODE` = 1

    select adc

  `AUDIO_HAL_CODEC_MODE_DECODE`

    select dac

  `AUDIO_HAL_CODEC_MODE_BOTH`

    select both adc and dac

  `AUDIO_HAL_CODEC_MODE_LINE_IN`

    set adc channel

enum `audio_hal_adc_input_t`

  Select adc channel for input mic signal.

  Values:

  `AUDIO_HAL_ADC_INPUT_LINE1` = 0x00

    mic input to adc channel 1

  `AUDIO_HAL_ADC_INPUT_LINE2`

    mic input to adc channel 2

  `AUDIO_HAL_ADC_INPUT_ALL`

    mic input to both channels of adc

  `AUDIO_HAL_ADC_INPUT_DIFFERENCE`

    mic input to adc difference channel

enum `audio_hal_dac_output_t`

  Select channel for dac output.

  Values:

  `AUDIO_HAL_DAC_OUTPUT_LINE1` = 0x00

    dac output signal to channel 1

  `AUDIO_HAL_DAC_OUTPUT_LINE2`

    dac output signal to channel 2

  `AUDIO_HAL_DAC_OUTPUT_ALL`

    dac output signal to both channels

enum `audio_hal_ctrl_t`

  Select operating mode i.e. start or stop for audio codec chip.

  Values:

  `AUDIO_HAL_CTRL_STOP` = 0x00

    set stop mode

  `AUDIO_HAL_CTRL_START` = 0x01

    set start mode

enum `audio_hal_iface_mode_t`

  Select I2S interface operating mode i.e. master or slave for audio codec chip.

  Values:

  `AUDIO_HAL_MODE_SLAVE` = 0x00

    set slave mode

  `AUDIO_HAL_MODE_MASTER` = 0x01

    set master mode

enum `audio_hal_iface_samples_t`

  Select I2S interface samples per second.

  Values:

  `AUDIO_HAL_08K_SAMPLES`

    set to 8k samples per second

  `AUDIO_HAL_11K_SAMPLES`

    set to 11.025k samples per second

  `AUDIO_HAL_16K_SAMPLES`

    set to 16k samples in per second

  `AUDIO_HAL_22K_SAMPLES`

    set to 22.050k samples per second

  `AUDIO_HAL_24K_SAMPLES`

    set to 24k samples in per second

  `AUDIO_HAL_32K_SAMPLES`

    set to 32k samples in per second

  `AUDIO_HAL_44K_SAMPLES`

    set to 44.1k samples per second

  `AUDIO_HAL_48K_SAMPLES`

    set to 48k samples per second

enum `audio_hal_iface_bits_t`

  Select I2S interface number of bits per sample.

  Values:

  `AUDIO_HAL_BIT_LENGTH_16BITS` = 1

    set 16 bits per sample

  `AUDIO_HAL_BIT_LENGTH_24BITS`

    set 24 bits per sample

  `AUDIO_HAL_BIT_LENGTH_32BITS`

    set 32 bits per sample

enum `audio_hal_iface_format_t`

  Select I2S interface format for audio codec chip.

  Values:

  `AUDIO_HAL_I2S_NORMAL` = 0

    set normal I2S format

  `AUDIO_HAL_I2S_LEFT`

    set all left format

  `AUDIO_HAL_I2S_RIGHT`

    set all right format

  `AUDIO_HAL_I2S_DSP`

    set dsp/pcm format

#### ES8388 Driver

Driver for ES8388 codec chip used in ESP32 LyraT audio board.

##### API Reference

###### Header File

- audio_hal/driver/es8388/es8388.h

###### Functions

esp_err_t `es8388_init`(audio_hal_codec_config_t *cfg)

  Initialize ES8388 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `cfg`: configuration of ES8388

esp_err_t `es8388_deinit`(void)

  Deinitialize ES8388 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

esp_err_t `es8388_config_fmt`(es_module_t mod, es_i2s_fmt_t cfg)

  Configure ES8388 I2S format.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mod`: set ADC or DAC or both

    - `cfg`: ES8388 I2S format

esp_err_t `es8388_i2s_config_clock`(es_i2s_clock_t cfg)

  Configure I2s clock in MSATER mode.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `cfg`: set bits clock and WS clock

esp_err_t `es8388_set_bits_per_sample`(es_module_t mode, es_bits_length_t bit_per_sample)

  Configure ES8388 data sample bits.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mode`: set ADC or DAC or both

    - `bit_per_sample`: bit number of per sample

esp_err_t `es8388_start`(es_module_t mode)

  Start ES8388 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mode`: set ADC or DAC or both

esp_err_t `es8388_stop`(es_module_t mode)

  Stop ES8388 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mode`: set ADC or DAC or both

esp_err_t `es8388_set_voice_volume`(int volume)

  Set voice volume.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `volume`: voice volume (0~100)

esp_err_t `es8388_get_voice_volume`(int *volume)

  Get voice volume.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[out] *volume`: voice volume (0~100)

esp_err_t `es8388_set_voice_mute`(bool enable)

  Configure ES8388 DAC mute or not. Basically you can use this function to mute the output or unmute.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `enable`: enable(1) or disable(0)

esp_err_t `es8388_get_voice_mute`(void)

  Get ES8388 DAC mute status.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

esp_err_t `es8388_set_mic_gain`(es_mic_gain_t gain)

  Set ES8388 mic gain.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `gain`: db of mic gain

esp_err_t `es8388_config_adc_input`(es_adc_input_t input)

  Set ES8388 adc input mode.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `input`: adc input mode

esp_err_t `es8388_config_dac_output`(es_dac_output_t output)

  Set ES8388 dac output mode.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `output`: dac output mode

esp_err_t `es8388_write_reg`(uint8_t reg_add, uint8_t data)

  Write ES8388 register.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `reg_add`: address of register

    - `data`: data of register

void `es8388_read_all`()

  Print all ES8388 registers.

  Return

    - void

esp_err_t `es8388_config_i2s`(audio_hal_codec_mode_t mode, audio_hal_codec_i2s_iface_t *iface)

  Configure ES8388 codec mode and I2S interface.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `mode`: codec mode

    - `iface`: I2S config

esp_err_t `es8388_ctrl_state`(audio_hal_codec_mode_t mode, audio_hal_ctrl_t ctrl_state)

  Control ES8388 codec chip.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `mode`: codec mode

    - `ctrl_state`: start or stop decode or encode progress

esp_err_t `es8388_pa_power`(bool enable)

  Set ES8388 PA power.

  Return

    - ESP_ERR_INVALID_ARG

    - ESP_OK

  Parameters

    - `enable`: true for enable PA power, false for disable PA power

###### Macros

`ES8388_ADDR`

  0x22:CE=1;0x20:CE=0

`ES8388_CONTROL1`

`ES8388_CONTROL2`

`ES8388_CHIPPOWER`

`ES8388_ADCPOWER`

`ES8388_DACPOWER`

`ES8388_CHIPLOPOW1`

`ES8388_CHIPLOPOW2`

`ES8388_ANAVOLMANAG`

`ES8388_MASTERMODE`

`ES8388_ADCCONTROL1`

`ES8388_ADCCONTROL2`

`ES8388_ADCCONTROL3`

`ES8388_ADCCONTROL4`

`ES8388_ADCCONTROL5`

`ES8388_ADCCONTROL6`

`ES8388_ADCCONTROL7`

`ES8388_ADCCONTROL8`

`ES8388_ADCCONTROL9`

`ES8388_ADCCONTROL10`

`ES8388_ADCCONTROL11`

`ES8388_ADCCONTROL12`

`ES8388_ADCCONTROL13`

`ES8388_ADCCONTROL14`

`ES8388_DACCONTROL1`

`ES8388_DACCONTROL2`

`ES8388_DACCONTROL3`

`ES8388_DACCONTROL4`

`ES8388_DACCONTROL5`

`ES8388_DACCONTROL6`

`ES8388_DACCONTROL7`

`ES8388_DACCONTROL8`

`ES8388_DACCONTROL9`

`ES8388_DACCONTROL10`

`ES8388_DACCONTROL11`

`ES8388_DACCONTROL12`

`ES8388_DACCONTROL13`

`ES8388_DACCONTROL14`

`ES8388_DACCONTROL15`

`ES8388_DACCONTROL16`

`ES8388_DACCONTROL17`

`ES8388_DACCONTROL18`

`ES8388_DACCONTROL19`

`ES8388_DACCONTROL20`

`ES8388_DACCONTROL21`

`ES8388_DACCONTROL22`

`ES8388_DACCONTROL23`

`ES8388_DACCONTROL24`

`ES8388_DACCONTROL25`

`ES8388_DACCONTROL26`

`ES8388_DACCONTROL27`

`ES8388_DACCONTROL28`

`ES8388_DACCONTROL29`

`ES8388_DACCONTROL30`

#### ES8374 Driver

Driver for ES8374 codec chip.

##### API Reference

###### Header File

- audio_hal/driver/es8374/es8374.h

###### Functions

esp_err_t `es8374_codec_init`(audio_hal_codec_config_t *cfg)

  Initialize ES8374 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `cfg`: configuration of ES8374

esp_err_t `es8374_codec_deinit`(void)

  Deinitialize ES8374 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

esp_err_t `es8374_config_fmt`(es_module_t mode, es_i2s_fmt_t fmt)

  Configure ES8374 I2S format.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mode`: set ADC or DAC or both

    - `fmt`: ES8374 I2S format

esp_err_t `es8374_i2s_config_clock`(es_i2s_clock_t cfg)

  Configure I2S clock in MSATER mode.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `cfg`: set bits clock and WS clock

esp_err_t `es8374_set_bits_per_sample`(es_module_t mode, es_bits_length_t bit_per_sample)

  Configure ES8374 data sample bits.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mode`: set ADC or DAC or both

    - `bit_per_sample`: bit number of per sample

esp_err_t `es8374_start`(es_module_t mode)

  Start ES8374 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mode`: set ADC or DAC or both

esp_err_t `es8374_stop`(es_module_t mode)

  Stop ES8374 codec chip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mode`: set ADC or DAC or both

esp_err_t `es8374_codec_set_voice_volume`(int volume)

  Set voice volume.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `volume`: voice volume (0~100)

esp_err_t `es8374_codec_get_voice_volume`(int *volume)

  Get voice volume.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[out] *volume`: voice volume (0~100)

esp_err_t `es8374_set_voice_mute`(bool enable)

  Mute or unmute ES8374 DAC. Basically you can use this function to mute or unmute the output.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `enable`: mute(1) or unmute(0)

esp_err_t `es8374_get_voice_mute`(void)

  Get ES8374 DAC mute status.

  Return

    - ESP_FAIL

    - ESP_OK

esp_err_t `es8374_set_mic_gain`(es_mic_gain_t gain)

  Set ES8374 mic gain.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `gain`: db of mic gain

esp_err_t `es8374_config_adc_input`(es_adc_input_t input)

  Set ES8374 ADC input mode.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `input`: adc input mode

esp_err_t `es8374_config_dac_output`(es_dac_output_t output)

  Set ES8374 DAC output mode.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `output`: dac output mode

esp_err_t `es8374_write_reg`(uint8_t reg_add, uint8_t data)

  Write ES8374 register.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `reg_add`: address of register

    - `data`: data of register

void `es8374_read_all`()

  Print all ES8374 registers.

  Return

    - void

esp_err_t `es8374_codec_config_i2s`(audio_hal_codec_mode_t mode, audio_hal_codec_i2s_iface_t *iface)

  Configure ES8374 codec mode and I2S interface.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `mode`: codec mode

    - `iface`: I2S config

esp_err_t `es8374_codec_ctrl_state`(audio_hal_codec_mode_t mode, audio_hal_ctrl_t ctrl_state)

  Control ES8374 codec chip.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `mode`: codec mode

    - `ctrl_state`: start or stop decode or encode progress

esp_err_t `es8374_pa_power`(bool enable)

  Set ES8374 PA power.

  Return

    - ESP_ERR_INVALID_ARG

    - ESP_OK

  Parameters

    - `enable`: true for enable PA power, false for disable PA power

###### Macros

`ES8374_ADDR`

#### ZL38063 Driver

Driver for ZL38063 codec chip used in ESP32-LyraTD-MSC audio board.

##### API Reference

###### Header File

- audio_hal/driver/zl38063/zl38063.h

###### Functions

esp_err_t `zl38063_codec_init`(audio_hal_codec_config_t *cfg)

  Initialize ZL38063 chip.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `cfg`: configuration of ZL38063

esp_err_t `zl38063_codec_deinit`(void)

  Deinitialize ZL38063 chip.

  Return

    - ESP_OK

    - ESP_FAIL

esp_err_t `zl38063_codec_ctrl_state`(audio_hal_codec_mode_t mode, audio_hal_ctrl_t ctrl_state)

  Control ZL38063 chip.

  The functions zl38063_ctrl_state and zl38063_config_i2s are not used by this driver. They are kept here to maintain the uniformity and convenience of the interface of the ADF project. These settings for zl38063 are burned in firmware and configuration files. Default i2s configuration: 48000Hz, 16bit, Left-Right channels. Use resampling to be compatible with different file types.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `mode`: codec mode

    - `ctrl_state`: start or stop decode or encode progress

esp_err_t `zl38063_codec_config_i2s`(audio_hal_codec_mode_t mode, audio_hal_codec_i2s_iface_t *iface)

  Configure ZL38063 codec mode and I2S interface.

  Return

    - ESP_FAIL Parameter error

    - ESP_OK Success

  Parameters

    - `mode`: codec mode

    - `iface`: I2S config

esp_err_t `zl38063_codec_set_voice_mute`(bool mute)

  mute or unmute the codec

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `mute`: true, false

esp_err_t `zl38063_codec_set_voice_volume`(int volume)

  Set voice volume.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `volume`: voice volume (0~100)

esp_err_t `zl38063_codec_get_voice_volume`(int *volume)

  Get voice volume.

  Return

    - ESP_OK

    - ESP_FAIL

  Parameters

    - `[out] *volume`: voice volume (0~100)

### Configuration Options

Compile-time configuration options specific to ESP-ADF.

#### Audio Codec Device Configuration

##### CODEC_I2C_BACKWARD_COMPATIBLE

> Enable backward compatibility for the I2C driver (force use of the old i2c_driver above v5.3)

> Found in: Component config > Audio Codec Device Configuration

> Enable this option for backward compatibility with the old I2C driver

##### CODEC_ES8311_SUPPORT

> Support ES8311 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ES8311.

##### CODEC_ES7210_SUPPORT

> Support ES7210 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ES7210.

##### CODEC_ES7243_SUPPORT

> Support ES7243 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ES7243.

##### CODEC_ES7243E_SUPPORT

> Support ES7243E Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ES7243E.

##### CODEC_ES8156_SUPPORT

> Support ES8156 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ES8156.

##### CODEC_AW88298_SUPPORT

> Support AW88298 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec AW88298.

##### CODEC_ES8374_SUPPORT

> Support ES8374 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ES8374.

##### CODEC_ES8388_SUPPORT

> Support ES8388 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ES8388.

##### CODEC_TAS5805M_SUPPORT

> Support TAS5805M Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec TAS5805M.

##### CODEC_ZL38063_SUPPORT

> Support ZL38063 Codec Chip

> Found in: Component config > Audio Codec Device Configuration

> Enable this option to support codec ZL38063. ZL38063 firmware only support xtensa, don’t enable for RISC-V IC.

#### Audio HAL

##### AUDIO_BOARD

> Audio board

> Found in: Audio HAL

> Select an audio board to use with the ESP-ADF

> Available options:

>   - AUDIO_BOARD_CUSTOM

>   - ESP_LYRAT_V4_3_BOARD

>   - ESP_LYRAT_V4_2_BOARD

>   - ESP_LYRATD_MSC_V2_1_BOARD

>   - ESP_LYRATD_MSC_V2_2_BOARD

>   - ESP_LYRAT_MINI_V1_1_BOARD

>   - ESP32_KORVO_DU1906_BOARD

>   - ESP32_S2_KALUGA_1_V1_2_BOARD

>   - ESP32_S3_KORVO2_V3_BOARD

>   - ESP32_S3_KORVO2L_V1_BOARD

>   - ESP32_S3_BOX_LITE_BOARD

>   - ESP32_S3_BOX_BOARD

>   - ESP32_S3_BOX_3_BOARD

>   - ESP32_C3_LYRA_V2_BOARD

>   - ESP32_C6_DEVKIT_BOARD

>   - ESP32_P4_FUNCTION_EV_BOARD

##### ESP32_KORVO_DU1906_DAC

> ESP32 KORVO DU1906 Board DAC chip

> Found in: Audio HAL

> Select DAC chip to use on ESP32_KORVO_DU1906 board

> Available options:

>   - ESP32_KORVO_DU1906_DAC_TAS5805M

>   - ESP32_KORVO_DU1906_DAC_ES7148

##### ESP32_KORVO_DU1906_ADC

> ESP32 KORVO DU1906 Board ADC chip

> Found in: Audio HAL

> Select ADC chip to use on ESP32_KORVO_DU1906 board

> Available options:

>   - ESP32_KORVO_DU1906_ADC_ES7243

#### ADF Features

##### ESP_DISPATCHER_DELEGATE_TASK_CORE

> Delegation task core

> Found in: ADF Features

> Pinned delegate task to core 0 or core 1.

##### ESP_DISPATCHER_DELEGATE_TASK_PRIO

> Delegate task’s prio

> Found in: ADF Features

> The delegate task’s prio.

##### ESP_DISPATCHER_DELEGATE_STACK_SIZE

> Delegate task’s stack size

> Found in: ADF Features

> The delegate task’s stack is located in DRAM, modify this size to make sure all the needed operation can be run success in the it.

#### DuerOS Service

##### DUEROS_GEN_PROFILE

> Generate the nvs partition which include the profile of dueros

> Found in: Component config > DuerOS Service

##### DUEROS_FLASH_PROFILE

> Flash the generated nvs partition

> Found in: Component config > DuerOS Service

##### DUEROS_DEVICE_NAME

> Duer device name

> Found in: Component config > DuerOS Service

#### ADF Library Configuration

##### MEDIA_PROTOCOL_LIB_ENABLE

> Enable Media Protocol Library

> Found in: ADF Library Configuration

##### MEDIA_LIB_MEM_AUTO_TRACE

> Support trace memory automatically after media_lib_sal init

> Found in: ADF Library Configuration

##### MEDIA_LIB_MEM_TRACE_DEPTH

> Memory trace stack depth

> Found in: ADF Library Configuration

> Set memory trace depth

##### MEDIA_LIB_MEM_TRACE_NUM

> Memory trace number

> Found in: ADF Library Configuration

> Set memory trace number

##### MEDIA_LIB_MEM_TRACE_MODULE

> Trace for module memory usage

> Found in: ADF Library Configuration

##### MEDIA_LIB_MEM_TRACE_LEAKAGE

> Trace for memory leakage

> Found in: ADF Library Configuration

##### MEDIA_LIB_MEM_TRACE_SAVE_HISTORY

> Trace to save memory history

> Found in: ADF Library Configuration

##### MEDIA_LIB_MEM_SAVE_CACHE_SIZE

> Cache buffer size to store save history

> Found in: ADF Library Configuration

> Set cache size for memory history

##### MEDIA_LIB_MEM_TRACE_SAVE_PATH

> Memory trace save path

> Found in: ADF Library Configuration

> Set memory trace save path

## Design Guide

The ESP32 is a powerful chip well positioned as a MCU of the audio projects. This section is intended to provide guidance on process of designing an audio project with the ESP32 inside.

### Project Design

[中文]

When designing a project with ability to process audio signals or audio data we typically consider a subset of the following components:

Input:

- Analog signal input to connect e.g. a microphone

- Storage media, e.g. microSD card with audio files to read

- Wi-Fi interface to obtain an audio data stream from the internet

- Bluetooth interface to obtain an audio data stream from e.g. a Bluetooth headset

- I2S interface to obtain audio data stream from a codec chip

- Ethernet interface to obtain an audio data stream from the internet

- An internal chip’s flash memory with some audio samples to play

- User Interface e.g. buttons or some other means to provide user input

Output:

- Analog signal output to connect headphones or speakers

- Storage media, e.g. microSD card to write some audio files, e.g. with recording

- Wi-Fi interface to send out an audio data stream to the internet

- Bluetooth interface to stream audio data to e.g. a Bluetooth headset

- I2S interface to stream some data to a codec chip

- Ethernet interface to stream an audio data stream to the internet

- An internal chip’s flash memory to store some audio recording

- User Interface e.g. a display, LEDs or some means of haptic feedback

Main Processing Unit:

A microcontroller or a computer with processing power to read the data from the input, process (e.g. encode / encode) and send to the output.

#### Project Options

The ESP chips (including ESP32, ESP32-S2, ESP32-S3) have all the above features or are able to support them (e.g. can drive Ethernet PHY). Considering the ESP chip cost is low, and availability of ESP-ADF software development platform, we are able to develop an audio project with minimum additional components at very low price.

Depending on the application, required functionality and performance, we may consider two project groups.

- Minimum - having minimum additional components, assuming using on board I2S, or PDM interface as well as DAC, if no high qualify audio on the output is required.

- Typical - with an external codec chip and a power amplifier, for high quality output audio and multiple input / output options.

There may be several variation between the above projects, by adding or removing features/components. Below are a couple of examples.

#### Project Minimum

With several peripherals on an ESP chip, I2S or PDM or DAC interfaces can be used to implement a minimum project. With the digital microphones, we could input voice signals and build a command voice control project minimum that could communicate with a cloud service.

Audio Project Example - Send Voice Commands to Cloud Service

With two on board DACs, if 8-bit width on the output is satisfactory, we may implement another project minimum - a device to play an internet connected radio.

Audio Project Example - Internet Connected Radio Player

#### Typical Project

When looking for better audio quality and more interfacing options we would use an external I2S codec to do all the analog input and output signal processing. The codec chip, depending on type, may provide additional functionality like audio input signal preamplifier, headphone output amplifier, multiple analog input and outputs, sound effects, etc. The I2S is considered as the industry standard for interfacing with audio codec chips, or in general for a high speed, continuous transfer of the audio data. To optimize performance of audio data processing, an additional memory may be required. For such cases, please consider using ESP32-WROVER-E that provides 8 MB PSRAM on a single module together with the ESP32 chip.

Typical Audio Project Example

The ESP-ADF is designed primarily to support projects with a codec chip. The ESP32 LyraT board is an example of such a project. The software interfacing with the board is done by Audio HAL and a driver. The codec chip used on the ESP32 LyraT is ES8388. Boards with a different codec chip may be supported by providing a different driver.

### Design Considerations

Depending on the audio data format, that may be lossless, lossy or compressed, e.g. WAV, MP3 or FLAC and the quality expressed in sampling rate and bitrate, the project will require different resources: memory, storage space, input / output throughput and the processing power. The resources will also depend on the project type and features discussed in Project Design.

This section describes capacity and performance of ESP32 system resources that should be considered when designing an audio project to meet required data format, audio quality and functionality.

#### Memory

The spare internal Data-RAM is about 290kB with “hello_world” example. For audio system this may be insufficient, and therefore the ESP32 incorporates the ability to use up to 4MB of external SPI RAM (i.e. PSRAM) memory. The external memory is incorporated in the memory map and is, within certain restrictions, usable in the same way internal Data-RAM is.

Refer to External SPI-connected RAM section in IDF documenation for details, especially pay attention to its Restrictions section which is very important.

To be able to use the PSRAM, if installed on your board, it should be enabled in menucofig under Component config > ESP32-specific > SPI RAM config. The option CONFIG_SPIRAM_CACHE_WORKAROUND, set by default in the same menu, should be kept enabled.

Note

Bluetooth and Wi-Fi can not coexist without PSRAM because it will not leave enough memory for an audio application.

##### Optimization of Internal RAM and Use of PSRAM

Internal RAM is more valuable asset since there are some restrictions on PSRAM. Here are some tips for optimizing internal RAM.

- If PSRAM is in use, set all the static buffer to minimum value in Component config > Wi-Fi; if PSRAM is not used then dynamic buffer should be selected to save memory. Refer to Wi-Fi Buffer Usage section in IDF documentation for details.

- If PSRAM and BT are used, then CONFIG_BT_ALLOCATION_FROM_SPIRAM_FIRST and CONFIG_BT_BLE_DYNAMIC_ENV_MEMORY should be set as “yes” under Component config > Bluetooth > Bluedroid Enable, to allocate more of 40kB memory to PSRAM

- If PSRAM and Wi-Fi are used, then CONFIG_WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST should be set as “yes” under Component config > ESP32-specific > SPI RAM config, to allocate some memory to PSRAM

- Set CONFIG_WL_SECTOR_SIZE as 512 in Component config > Wear Levelling

Note

The smaller the size of sector be, the slower the Write / Read speed will be, and vice versa, but only 512 and 4096 are supported.

- Call `char *buf = heap_caps_malloc(1024 * 10, MALLOC_CAP_SPIRAM | MALLOC_CAP_8BIT)` instead of `malloc(1024 * 10)` to use PSRAM, and call `char *buf = heap_caps_malloc(512, MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT)` to use internal RAM.

- Not relying on `malloc()` to automatically allocate PSRAM allows to make a full control of the memory. By avoiding the use of the internal RAM by other `malloc()` calls, you can reserve more memory for high-efficiency usage and task stack since PSRAM cannot be used as task stack memory.

- The task stack will always be allocated at internal RAM. On the other hand you can use of the `xTaskCreateStatic()` function that allows to create tasks with stack on PSRAM (see options in PSRAM and FreeRTOS menuconfig), but pay attention to its help information.

Important

Don’t use ROM code in `xTaskCreateStatic` task： The ROM code itself is linked in `components/esp32/ld/esp32.rom.ld`. However, you also need to consider other pieces of code that call ROM functions, as well as the code that is not recompiled against the CONFIG_SPIRAM_CACHE_WORKAROUND patch, like the Wi-Fi and Bluetooth libraries. In general, we advise using this only in threads that do not call any IDF libraries (including libc), doing only calculations and using FreeRTOS primitives to talk to other threads.

##### Memory Usage by Component Overview

Below is a table that contains ESP-ADF components and their memory usage. Choose the components needed and find out how much internal RAM is left. The table is divided into two parts, when PSRAM is used or not. If PSRAM (external RAM) is in use, then some of the memory will be allocated at PSRAM automatically.

The initial spare internal RAM is 290kB.

Component | Internal RAM Required
--- | ---
PSRAM not used | With PSRAM
Wi-Fi 1 | 50kB+ | 50kB+
Bluetooth | 140kB (50kB if only BLE needed) | 95kB (50kB if only BLE needed)
Flash Card 2 | 12kB+ | 12kB+
I2S 3 | Configurable, 8kB for reference | Configurable, 8kB for reference
RingBuffer 4 | Configurable, 30kB for reference | 0kB, all moved into PSRAM

Notes to the table above

1. According to the Wi-Fi menuconfig each Tx and Rx buffer occupies 1.6kB internal RAM. The value of 50kB RAM is assuming use of 5 Rx static buffers and 6 Tx static buffers. If PSRAM is not in use, then the “Type of WiFi Tx Buffer” option should be set as DYNAMIC in order to save RAM, in this case, the RAM usage will be far less than 50kB, but programmer should keep at least 50kB available for the Wi-Fi to be able to transmit the data. [Internal RAM only]

2. Taking ESP32-LyraT V4.3 as an example, depending on value of SDCARD_OPEN_FILE_NUM_MAX in audio_board/lyrat_v4_3/board_def.h, that is then used in `sdcard_mount()` function, the RAM needed will increase with a greater number of maximum open files. 12kB is the RAM needed with 5 max files and 512 bytes CONFIG_WL_SECTOR_SIZE. [Internal RAM only]

3. Depending on configuration settings of the I2S stream, refer to audio_stream/include/i2s_stream.h and audio_stream/i2s_stream.c. [Internal RAM only]

4. Depending on configuration setting of the Ringbuffer, refer to DEFAULT_PIPELINE_RINGBUF_SIZE in audio_pipeline/include/audio_pipeline.h or user setting, if the buffer is created with e.g. `rb_create()`.

#### System Settings

The following settings are recommended to achieve a high Wi-Fi performance in an audio project.

Note

Use ESP32 modules and boards from reputable vendors that put attention to product design, component selection and product testing. This is to have confidence of receiving well designed boards with calibrated RF.

- Set these following options in menuconfig.

  > - Flash SPI mode as QIO

  > - Flash SPI speed as 80MHz

  > - CPU frequency as 240MHz

  > - Set Default receive window size as 5 times greater than Maximum Segment Size in Component config > LWIP > TCP

- If external antenna is used, then set PHY_RF_CAL_PARTIAL as PHY_RF_CAL_FULL in ‘’esp-idf/components/esp32/phy_init.c’’

### Software Design

Espressif audio framework project.

#### Features

1. All of Streams and Codecs based on audio element.

2. All events based on queue.

3. Audio pipeline supports dynamic combination.

4. Audio pipeline supports multiple elements.

5. Pipeline Support functionality plug-in.

6. Audio common peripherals support work in the one task.

7. Support post-event mechanism in peripherals.

8. Support high level audio play API based on element and audio pipeline.

9. Audio high level interface supports dynamic adding of codec library.

10. Audio high level interface supports dynamic adding of input and output stream.

11. ESP audio supports multiple audio pipelines.

#### Design Components

Five basic components are - Audio Element, Audio Event, Audio Pipeline, ESP peripherals, ESP audio

##### Audio Element

###### Example

Please refer to audio_stream/fatfs_stream.c for an example of using an audio element.

##### Audio Event

###### Example

Please refer to player/pipeline_http_mp3/main/play_http_mp3_example.c for an example of using an audio event.

##### Audio Pipeline

###### Example

Please refer to player/pipeline_play_sdcard_music/main/play_sdcard_music_example.c for an example of linking elements into an audio pipeline.

##### Audio Peripheral

###### Example

    ESP_LOGI(TAG, "[ 3 ] Start and wait for Wi-Fi network");
    esp_periph_config_t periph_cfg = DEFAULT_ESP_PERIPH_SET_CONFIG();
    esp_periph_set_handle_t set = esp_periph_set_init(&periph_cfg);
    periph_wifi_cfg_t wifi_cfg = {
        .wifi_config.sta.ssid = CONFIG_WIFI_SSID,
        .wifi_config.sta.password = CONFIG_WIFI_PASSWORD,
    };
    esp_periph_handle_t wifi_handle = periph_wifi_init(&wifi_cfg);
    esp_periph_start(set, wifi_handle);
    periph_wifi_wait_for_connected(wifi_handle, portMAX_DELAY);

##### Audio Player

###### Example

Please refer to cli for an example of initializing `esp_audio` as an audio player.

### Development Boards

Below are getting started guides and hardware details of audio development boards designed by Espressif.

Getting Started with ESP32-LyraT | Getting Started with ESP32-LyraT-Mini
Hardware Reference of ESP32-LyraT | Hardware Reference of ESP32-LyraT-Mini
Getting Started with ESP32-LyraTD-MSC | Getting Started with ESP32-S2-Kaluga-1-Kit
Getting Started with ESP32-Korvo-DU1906 | Getting Started with ESP32-S3-Korvo-2
Getting Started with ESP32-C3-Lyra |

#### ESP32-LyraT-Mini V1.2 Getting Started Guide

[中文]

This guide provides users with functional descriptions, configuration options for ESP32-LyraT-Mini V1.2 audio development board, as well as how to get started with the ESP32-LyraT board.

The ESP32-LyraT is a hardware platform designed for the dual-core ESP32 audio applications, e.g., Wi-Fi or BT audio speakers, speech-based remote controllers, connected smart-home appliances with one or more audio functionality, etc.

The ESP32-LyraT-Mini is a mono audio board. If you are looking for a stereo audio board, check ESP32-LyraT V4.3 Getting Started Guide.

##### What You Need

- ESP32-LyraT-Mini V1.2 board

- Speaker or headphones with a 3.5 mm jack. If you use a speaker, it is recommended to choose one no more than 3 watts, and JST PH 2.0 2-Pin plugs are needed. In case you do not have this type of plug it is also fine to use Dupont female jumper wires during development.

- Two Micro-USB 2.0 cables, Type A to Micro B

- PC loaded with Windows, Linux or Mac OS

Optional components

- Micro SD-card

- Li-ion Battery

If you like to start using this board right now, go directly to section Start Application Development.

###### Overview

The ESP32-LyraT-Mini V1.2 is an audio development board produced by Espressif built around ESP32. It is intended for audio applications, by providing hardware for audio processing and additional RAM on top of what is already on-board of the ESP32 chip. The specific hardware includes:

- ESP32-WROVER-E module

- Audio codec chip

- ADC chip

- Microphone on board

- Audio output

- 1 x 3-watt speaker output

- MicroSD card slot (1 line)

- Eight keys

- Two system LEDs

- JTAG and UART test points

- Integrated USB-UART Bridge Chip

- Li-ion Battery-Charge Management

The block diagram below presents main components of the ESP32-LyraT-Mini and interconnections between components.

ESP32-LyraT-Mini Block Diagram

###### Components

The following list and figure describe key components, interfaces and controls of the ESP32-LyraT-Mini used in this guide. For detailed technical documentation of this board, please refer to ESP32-LyraT-Mini V1.2 Hardware Reference and ESP32-LyraT-Mini V1.2 schematic (PDF). The list below provides description starting from the picture’s top right corner and going clockwise.

Audio Codec Chip

  The audio codec chip, ES8311, is a low power mono audio codec. It consists of 1-channel ADC, 1-channel DAC, low noise pre-amplifier, headphone driver, digital sound effects, analog mixing and gain functions. It is interfaced with ESP32-WROVER-E Module over I2S and I2C buses to provide audio processing in hardware independently from the audio application.

Audio Output

  Output socket to connect headphones with a 3.5 mm stereo jack. (Please note that the board outputs a mono signal)

Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

ESP32 LyraT-Mini V1.2 Board Layout Overview

USB-UART Port

  Functions as the communication interface between a PC and the ESP32.

USB Power Port

  Provides the power supply for the board.

Standby / Charging LEDs

  The Standby green LED indicates that power has been applied to the USB Power Port. The Charging red LED indicates that a battery connected to the Battery Socket is being charged.

Power On Switch

  Power on/off knob: toggling it to the top powers the board on; toggling it to the down powers the board off.

Power On LED

  Red LED indicating that Power On Switch is turned on.

ESP32-WROVER-E Module

  The ESP32-WROVER-E module contains ESP32 chip to provide Wi-Fi / Bluetooth connectivity and data processing power as well as integrates 4 MB external SPI flash and an additional 8 MB PSRAM for flexible data storage.

##### Start Application Development

Before powering up the ESP32-LyraT-Mini, please make sure that the board has been received in good condition with no obvious signs of damage.

###### Initial Setup

Prepare the board for loading of the first sample application:

1. Connect speaker to the Speaker Output. Connecting headphones to the Audio Output is an option.

2. Plug in the Micro-USB cables to the PC and to both USB ports of the ESP32-LyraT-Mini.

3. The Standby LED (green) should turn on. Assuming that a battery is not connected, the Charging LED (red) will blink every couple of seconds.

4. Toggle top the Power On Switch.

5. The red Power On LED should turn on.

If this is what you see on the LEDs, the board should be ready for application upload. Now prepare the PC by loading and configuring development tools what is discussed in the next section.

###### Develop Applications

Once the board is initially set up and checked, you can start preparing the development tools. The Section Installation Step by Step will walk you through the following steps:

- Set up ESP-IDF to get a common development framework for the ESP32 (and ESP32-S2) chips in C language;

- Get ESP-ADF to install the API specific to audio applications;

- Set up env to make the framework aware of the audio specific API;

- Start a Project that will provide a sample audio application for the board;

- Connect Your Device to prepare the application for loading;

- Build the Project to finally run the application and play some music.

##### Revision History

- Changed the integrated module to ESP32-WROVER-E from ESP32-WROVER-B.

##### Other Boards from LyraT Family

- ESP32-LyraT V4.3 Getting Started Guide

- ESP32-LyraTD-MSC V2.2 Getting Started Guide

##### Related Documents

- ESP32-LyraT-Mini V1.2 schematic (PDF)

- ESP32-LyraT-Mini V1.2 Board Dimensions (PDF)

- ESP32-LyraT-Mini V1.2 Hardware Reference

- ESP32 Datasheet (PDF)

- ESP32-WROVER-E Datasheet (PDF)

#### ESP32-LyraT-Mini V1.2 Hardware Reference

This guide provides functional descriptions and configuration options for ESP32-LyraT-Mini V1.2 audio development board. As an introduction to functionality and using the LyraT, please see ESP32-LyraT-Mini V1.2 Getting Started Guide.

In this Section

- Overview

- Functional Description

- Allocation of ESP32 Pins to Test Points

  - JTAG Test Point

  - UART Test Point

- MicroSD Card

- GPIO Allocation Summary

- Notes on Power Distribution

  - Power Supply over USB and from Battery

  - Independent Audio and Digital Power Supply

- Selecting of the Audio Output

- Related Documents

##### Overview

ESP32-LyraT is a hardware platform designed for the dual-core ESP32 audio applications, e.g., Wi-Fi or BT audio speakers, speech-based remote controllers, connected smart-home appliances with one or more audio functionality, etc.

The block diagram below presents main components of ESP32-LyraT-Mini.

ESP32-LyraT-Mini V1.2 Electrical Block Diagram

##### Functional Description

The following list and figure describe key components, interfaces, and controls of the ESP32-LyraT-Mini board. The list provides description starting from the picture’s top right corner and going clockwise.

MicroSD Slot

  The development board supports a MicroSD card in SPI/1-bit modes, and can store or play audio files in the MicroSD card. See MicroSD Card for pinout details.

Microphone

  On-board microphone connected to AINRP/AINRP of the Audio ADC Chip.

System LEDs

  Two general purpose LEDs (green and red) controlled by ESP32-WROVER-E Module to indicate certain operation states of the audio application using dedicated API.

Audio Codec

  The audio codec chip, ES8311, is a low power mono audio codec. It consists of 1-channel ADC, 1-channel DAC, low noise pre-amplifier, headphone driver, digital sound effects, analog mixing, and gain functions. It is interfaced with ESP32-WROVER-E Module over I2S and I2C buses to provide audio processing in hardware independently from the audio application.

Audio Output

  Output socket to connect headphones with a 3.5 mm stereo jack. One of the socket’s terminals is wired to ESP32 to provide jack insertion detection.

ADC

  The audio codec chip, ES7243, is a low power multi-bit delta-sigma audio ADC and DAC. In this board this chip is used as the microphone interface.

PA

  A power amplifier used to amplify the audio signal from the Audio Codec Chip for driving the speaker.

Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

Function Press Keys

  Six press keys labeled Rec, Mode, Play, Set, Vol-, and Vol+. They are routed to ESP32-WROVER-E Module and intended for development and testing of a UI for audio applications using dedicated API.

ESP32 LyraT-Mini V1.2 Board Layout

Boot/Reset Press Keys

  Boot: holding down the Boot button and momentarily pressing the Reset button initiates the firmware upload mode. Then user can upload firmware through the serial port. Reset: pressing this button alone resets the system.

Automatic Upload

  A simple two transistor circuit to put ESP32 into firmware upload mode depending on the status of UART DTR and RTS signals. The signals are controlled by an external application to upload the firmware over the USB-UART interface.

USB-UART Port

  Functions as the communication interface between a PC and the ESP32 module.

USB-UART Bridge

  A single chip USB-UART bridge CP2102N provides up to 3 Mbps transfers rates.

USB Power Port

  Provides the power supply for the board.

Standby/Charging LEDs

  The Standby green LED indicates that power has been applied to the USB Power Port. The Charging red LED indicates that a battery connected to the Battery Socket is being charged.

Battery Socket

  Two-pin socket to connect a single cell Li-ion battery. The pins have a 2.00 mm / 0.08” pitch. The battery serves as an alternative power supply to the USB Power Port for charging the board. Make sure to use a Li-ion battery that has protection circuit and fuse. The recommended specifications of the battery: capacity > 1000 mAh, output voltage 3.7 V, input voltage 4.2 V – 5 V. Please verify if polarity on the battery plug matches polarity of the socket as marked on the board’s soldermask besides the socket.

Battery Charger

  Constant current and constant voltage linear charger for single cell lithium-ion batteries AP5056. Used for charging of a battery connected to the Battery Socket over the USB Power Port.

Power Supervisor

  Provides EN signal to enable ESP32 once power supply voltage stabilizes.

Power On Switch

  Power on/off knob: toggling it to the top powers the board on; toggling it to the down powers the board off.

  Note

  The Power On Switch does not affect / disconnect the Li-ion battery charging. More information, you can refer to ESP32-LyraT-Mini V1.2 schematic (PDF).

Power On LED

  Red LED indicating that Power On Switch is turned on.

ESP32-WROVER-E Module

  The ESP32-WROVER-E module contains ESP32 chip to provide Wi-Fi / Bluetooth connectivity and data processing power as well as integrates 4 MB external SPI flash and an additional 8 MB PSRAM for flexible data storage.

UART Termininals

  Serial port: provides access to the serial TX/RX signals between ESP32-WROVER-E Module and USB-UART Bridge Chip. See UART Test Point for pinout details.

JTAG Termininals

  Provides access to the JTAG interface of ESP32-WROVER-E Module. It may be used for debugging, application upload, as well as implementing several other functions, e.g., Application Level Tracing. See JTAG Test Point for pinout details.

##### Allocation of ESP32 Pins to Test Points

This section describes allocation of test points available on the ESP32-LyraT-Mini board.

The test points are bare through hole solder pads and have standard 2.54 mm / 0.1 inch pitch. User may need to populate them with pin headers or sockets for easy connection of external hardware.

###### JTAG Test Point

. | ESP32 Pin | JTAG Signal
--- | --- | ---
1 | MTDO / GPIO15 | TDO
2 | MTCK / GPIO13 | TCK
3 | MTDI / GPIO12 | TDI
4 | MTMS / GPIO14 | TMS

###### UART Test Point

. | ESP32 Pin | Pin Description
--- | --- | ---
1 | RXD0 | RX
2 | TXD0 | TX
3 | GND | GND
4 | n/a | 3.3 V

##### MicroSD Card

Implemented on this board MicoSD card interface operates in SPI/1-bit mode. The board is able to support SPI/4-b it mode after populating couple of additional components on locations reserved on the PCB. See ESP32-LyraT-Mini V1.2 schematic (PDF) for additional information. Not populated components are marked (NC) on the schematic.

. | ESP32 Pin | MicroSD Signal
--- | --- | ---
1 | MTDI / GPIO12 | –
2 | MTCK / GPIO13 | –
3 | MTDO / GPIO15 | CMD
4 | MTMS / GPIO14 | CLK
5 | GPIO2 | DATA0
6 | GPIO4 | –
7 | GPIO34 | CD

##### GPIO Allocation Summary

The table below provides allocation of GPIOs exposed on terminals of ESP32-WROVER-E Module to control specific components or functions of the board.

Pin 1 | Pin Name | ES8311 | ES7243 | Keys | MicroSD | Other
--- | --- | --- | --- | --- | --- | ---
3 | EN |  |  | EN_KEY |  |
4 | S_VP |  | I2S_DATA |  |  |
5 | S_VN |  |  | REC, MODE, PLAY, SET, VOL-, VOL+ |  |
6 | IO34 |  |  |  | CD |
7 | IO35 | I2S0_ASDOUT |  |  |  |
8 | IO32 |  | I2S1_SCLK |  |  |
9 | IO33 |  | I2S1_LRCK |  |  |
10 | IO25 | I2S0_LRCK |  |  |  |
11 | IO26 | I2S0_DSDIN |  |  |  |
12 | IO27 |  |  |  |  | Blue_LED
13 | IO14 |  |  |  | CLK |
14 | IO12 |  |  |  | NC (DATA2) |
16 | IO13 |  |  |  | NC (DATA3) |
17 | SD2 |  |  |  |  |
18 | SD3 |  |  |  |  |
19 | CMD |  |  |  |  |
20 | CLK |  |  |  |  |
21 | SD0 |  |  |  |  |
22 | SD1 |  |  |  |  |
23 | IO15 |  |  |  | CMD |
24 | IO2 |  |  | IO2_KEY | DATA0 |
25 | IO0 | I2S0_MCLK | I2S1_MCLK | IO0_KEY |  |
26 | IO4 |  |  |  | NC (DATA1) |
27 | NC (IO16) |  |  |  |  |
28 | NC (IO17) |  |  |  |  |
29 | IO5 | I2S0_SCLK |  |  |  |
30 | IO18 | I2C_SDA | I2C_SDA |  |  |
31 | IO19 |  |  |  |  | PJ_DET 2
33 | IO21 |  |  |  |  | PA_CTRL 3
34 | RXD0 |  |  |  |  | RXD0 4
35 | TXD0 |  |  |  |  | TXD0 4
36 | IO22 |  |  |  |  | Green_LED
37 | IO23 | I2C_SCK | I2C_SCL |  |  |

1. Pin - ESP32-WROVER-E module pin number, GND and power supply pins are not listed

2. PJ_DET - phone jack insertion detect signal

3. PA_CTRL - NS4150 power amplifier chip control signal

4. RXD0, TXD0 - serial communication signals connected to TXD and RXD pins of CP2102N USB-UART bridge

5. NC - not connected

##### Notes on Power Distribution

The ESP32-LyraT-Mini board provides some basic features to isolate noise from digital components by providing separate power distribution for audio and digital subsystems.

###### Power Supply over USB and from Battery

There are two ways to power the development board: 5 V USB Power Port or 3.7 V optional battery. The optional battery is preferable for applications where a cleaner power supply is required.

ESP32-LyraT-Mini V1.2 - Dedicated USB Power Supply Socket

ESP32-LyraT-Mini V1.2 - Power Supply from a Battery

###### Independent Audio and Digital Power Supply

The board features independent power supplies to the audio components and the ESP32 module. This should reduce noise in the audio signal from digital components and improve overall performance of the components.

ESP32-LyraT-Mini V1.2 - Digital Power Supply

ESP32-LyraT-Mini V1.2 - Audio Power Supply

##### Selecting of the Audio Output

The board provides a mono audio output signal on pins OUTN and OUTP of the ES8311 codec chip. The signal is routed to two outputs:

- Power amplifier (PA) to drive an external speaker

- Phone jack socket to drive external headphones

The board design assumes that selection between one of these outputs is implemented in software, as opposed to using traditional mechanical contacts in a phone jack socket, that would disconnect the speaker once a headphone jack is inserted.

Two digital IO signals are provided to implement selection between the speaker and the headphones:

- PJ_DET - digital input signal to o detect when a headphone jack is inserted,

- PA_CTRL - digital output signal to enable or disable the amplifier IC.

The application running on ESP32 may then enable or disable the PA with PA_CTRL basing on status of PJ_DET. Please see GPIO Allocation Summary for specific GPIO numbers allocated to these signals.

##### Related Documents

- ESP32-LyraT-Mini V1.2 Schematic (PDF)

- ESP32-LyraT-Mini V1.2 Board Dimensions (PDF)

- ESP32-LyraT-Mini V1.2 Getting Started Guide

- ESP32 Datasheet (PDF)

- ESP32-WROVER-E Datasheet (PDF)

#### ESP32-LyraT V4.3 Getting Started Guide

[中文]

This guide provides users with functional descriptions, configuration options for ESP32-LyraT V4.3 audio development board, as well as how to get started with the ESP32-LyraT board. Check section Other Versions of LyraT, if you have different version of this board.

The ESP32-LyraT is a hardware platform designed for the dual-core ESP32 audio applications, e.g., Wi-Fi or Bluetooth audio speakers, speech-based remote controllers, connected smart-home appliances with one or more audio functionality, etc.

The ESP32-LyraT is a stereo audio board. If you are looking for a mono audio board, intended for lower end applications, check ESP32-LyraT-Mini V1.2 Getting Started Guide.

##### What You Need

- 1 × ESP32 LyraT V4.3 board

- 2 x Speaker or headphones with a 3.5 mm jack. If you use a speaker, it is recommended to choose one no more than 3 watts, and JST PH 2.0 2-Pin plugs are needed. In case you do not have this type of plug it is also fine to use Dupont female jumper wires during development.

- 2 x Micro-USB 2.0 cables, Type A to Micro B

- 1 × PC loaded with Windows, Linux or Mac OS

If you like to start using this board right now, go directly to section Start Application Development.

###### Overview

The ESP32-LyraT V4.3 is an audio development board produced by Espressif built around ESP32. It is intended for audio applications, by providing hardware for audio processing and additional RAM on top of what is already onboard of the ESP32 chip. The specific hardware includes:

- ESP32-WROVER-E Module

- Audio Codec Chip

- Dual Microphones on board

- Headphone output

- 2 x 3-watt Speaker output

- Dual Auxiliary Input

- MicroSD Card slot (1 line or 4 lines)

- Six buttons (2 physical buttons and 4 touch buttons)

- JTAG header

- Integrated USB-UART Bridge Chip

- Li-ion Battery-Charge Management

The block diagram below presents main components of the ESP32-LyraT and interconnections between components.

ESP32-LyraT Block Diagram

###### Components

The following list and figure describe key components, interfaces and controls of the ESP32-LyraT used in this guide. This covers just what is needed now. For detailed technical documentation of this board, please refer to ESP32-LyraT V4.3 Hardware Reference and ESP32 LyraT V4.3 schematic (PDF).

ESP32-WROVER-E Module

  The ESP32-WROVER-E module contains ESP32 chip to provide Wi-Fi / Bluetooth connectivity and data processing power as well as integrates 4 MB external SPI flash and an additional 8 MB PSRAM for flexible data storage.

Headphone Output

  Output socket to connect headphones with a 3.5 mm stereo jack.

  Note

  The socket may be used with mobile phone headsets and is compatible with OMPT standard headsets only. It does not work with CTIA headsets. Please refer to Phone connector (audio) on Wikipedia.

ESP32-LyraT V4.3 Board Layout Overview

Left Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

Right Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

Boot/Reset Press Keys

  Boot: holding down the Boot button and momentarily pressing the Reset button initiates the firmware upload mode. Then user can upload firmware through the serial port. Reset: pressing this button alone resets the system.

Audio Codec Chip

  The Audio Codec Chip, ES8388, is a low power stereo audio codec with a headphone amplifier. It consists of 2-channel ADC, 2-channel DAC, microphone amplifier, headphone amplifier, digital sound effects, analog mixing and gain functions. It is interfaced with ESP32-WROVER-E Module over I2S and I2S buses to provide audio processing in hardware independently from the audio application.

USB-UART Port

  Functions as the communication interface between a PC and the ESP32-WROVER-E Module.

USB Power Port

  Provides the power supply for the board.

Standby / Charging LEDs

  The Standby green LED indicates that power has been applied to the Micro USB Port. The Charging red LED indicates that a battery connected to the Battery Socket is being charged.

Power Switch

  Power on/off knob: toggling it to the left powers the board on; toggling it to the right powers the board off.

Power On LED

  Red LED indicating that Power On Switch is turned on.

##### Start Application Development

Before powering up the ESP32-LyraT, please make sure that the board has been received in good condition with no obvious signs of damage.

###### Initial Setup

Prepare the board for loading of the first sample application:

1. Connect speakers to the Right and Left Speaker Output. Connecting headphones to the Headphone Output is an option.

2. Plug in the Micro-USB cables to the PC and to both USB ports of the ESP32 LyraT.

3. The Standby LED (green) should turn on. Assuming that a battery is not connected, the Charging LED (red) will blink every couple of seconds.

4. Toggle left the Power On Switch.

5. The red Power On LED should turn on.

If this is what you see on the LEDs, the board should be ready for application upload. Now prepare the PC by loading and configuring development tools what is discussed in the next section.

###### Develop Applications

Once the board is initially set up and checked, you can start preparing the development tools. The Section Installation Step by Step will walk you through the following steps:

- Set up ESP-IDF to get a common development framework for the ESP32 (and ESP32-S2) chips in C language;

- Get ESP-ADF to install the API specific to audio applications;

- Set up env to make the framework aware of the audio specific API;

- Start a Project that will provide a sample audio application for the board;

- Connect Your Device to prepare the application for loading;

- Build the Project to finally run the application and play some music.

##### Summary of Key Changes from LyraT V4.2

- Changed the integrated module to ESP32-WROVER-E from ESP32-WROVER.

- Removed Red LED indicator light.

- Introduced headphone jack insert detection.

- Replaced single Power Amplifier (PA) chip with two separate chips.

- Updated power management design of several circuits: Battery Charging, ESP32, MicorSD, Codec Chip and PA.

- Updated electrical implementation design of several circuits: UART, Codec Chip, Left and Right Microphones, AUX Input, Headphone Output, MicroSD, Push Buttons and Automatic Upload.

##### Other Versions of LyraT

- ESP32-LyraT V4.2 Getting Started Guide

- ESP32-LyraT V4 Getting Started Guide

##### Other Boards from LyraT Family

- ESP32-LyraT-Mini V1.2 Getting Started Guide

- ESP32-LyraTD-MSC V2.2 Getting Started Guide

##### Related Documents

- ESP32-LyraT V4.3 Hardware Reference

- ESP32 LyraT V4.3 schematic (PDF)

- ESP32-LyraT V4.3 Component Layout (PDF)

- ESP32 Datasheet (PDF)

- ESP32-WROVER-E Datasheet (PDF)

#### ESP32-LyraT V4.3 Hardware Reference

This guide provides functional descriptions, configuration options for ESP32-LyraT V4.3 audio development board. As an introduction to functionality and using the LyraT, please see ESP32-LyraT V4.3 Getting Started Guide. Check section Other Versions of LyraT if you have different version of the board.

In this Section

- Overview

- Functional Description

  - Hardware Setup Options

    - Enable MicroSD Card in 1-wire Mode

    - Enable MicroSD Card in 4-wire Mode

    - Enable JTAG

    - Using Automatic Upload

  - Allocation of ESP32 Pins

  - Pinout of Extension Headers

    - UART Header / JP2

    - I2S Header / JP4

    - I2C Header / JP5

    - JTAG Header / JP7

  - Notes of Power Distribution

    - Power Supply Separation

    - Three Dedicated LDOs

    - Separate Power Feed for the PAs

  - Selecting of the Audio Output

- Other Versions of LyraT

- Related Documents

##### Overview

The ESP32-LyraT development board is a hardware platform designed for the dual-core ESP32 audio applications, e.g., Wi-Fi or BT audio speakers, speech-based remote controllers, smart-home appliances with audio functionality(ies), etc.

The block diagram below presents main components of the ESP32-LyraT.

ESP32-LyraT V4.3 Electrical Block Diagram

##### Functional Description

The following list and figure describe key components, interfaces and controls of the ESP32-LyraT board.

ESP32-WROVER-E Module

  The ESP32-WROVER-E module contains ESP32 chip to provide Wi-Fi / Bluetooth connectivity and data processing power as well as integrates 4 MB external SPI flash and an additional 8 MB PSRAM for flexible data storage.

Green LED

  A general purpose LED controlled by the ESP32-WROVER-E Module to indicate certain operation states of the audio application using dedicated API.

Function DIP Switch

  Used to configure function of GPIO12 to GPIO15 pins that are shared between devices, primarily between JTAG Header and MicroSD Card. By default, the MicroSD Card is enabled with all switches in OFF position. To enable the JTAG Header instead, switches in positions 3, 4, 5 and 6 should be put ON. If JTAG is not used and MicroSD Card is operated in the one-line mode, then GPIO12 and GPIO13 may be assigned to other functions. Please refer to ESP32 LyraT V4.3 schematic for more details.

JTAG Header

  Provides access to the JTAG interface of ESP32-WROVER-E Module. It may be used for debugging, application upload, as well as implementing several other functions, e.g., Application Level Tracing. See JTAG Header / JP7 for pinout details. Before using JTAG signals to the header, Function DIP Switch should be enabled. Please note that when JTAG is in operation, MicroSD Card cannot be used and should be disconnected because some of JTAG signals are shared by both devices.

UART Header

  Serial port: provides access to the serial TX/RX signals between ESP32-WROVER-E Module and USB-UART Bridge Chip.

I2C Header

  Provides access to the I2C interface. Both ESP32-WROVER-E Module and Audio Codec Chip are connected to this interface. See I2C Header / JP5 for pinout details.

MicroSD Slot

  The development board supports a MicroSD card in SPI/1-bit/4-bit modes, and can store or play audio files in the MicroSD card. Note that JTAG cannot be used and should be disconnected by setting Function DIP Switch when MicroSD Card is in operation, because some of signals are shared by both devices.

I2S Header

  Provides access to the I2S interface. Both ESP32-WROVER-E Module and Audio Codec Chip are connected to this interface. See I2S Header / JP4 for pinout details.

Left Microphone

  Onboard microphone connected to IN1 of the Audio Codec Chip.

AUX Input

  Auxiliary input socket connected to IN2 (left and right channel) of the Audio Codec Chip. Use a 3.5 mm stereo jack to connect to this socket.

Headphone Output

  Output socket to connect headphones with a 3.5 mm stereo jack.

  Note

  The socket may be used with mobile phone headsets and is compatible with OMPT standard headsets only. It does work with CTIA headsets. Please refer to Phone connector (audio) on Wikipedia.

ESP32-LyraT V4.3 Board Layout

Right Microphone

  Onboard microphone connected to IN1 of the Audio Codec Chip.

Left Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

Right Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

PA Chip

  A power amplifier used to amplify stereo audio signal from the Audio Codec Chip for driving two speakers.

Boot/Reset Press Keys

  Boot button: holding down the Boot button and momentarily pressing the Reset button to initiate the firmware download mode. Then you can download firmware through the serial port. Reset button: pressing this button alone resets the system.

Touch Pad Buttons

  Four touch pads labeled Play, Sel, Vol+ and Vol-. They are routed to ESP32-WROVER-E Module and intended for development and testing of a UI for audio applications using dedicated API.

Audio Codec Chip

  The Audio Codec Chip, ES8388, is a low power stereo audio codec with a headphone amplifier. It consists of 2-channel ADC, 2-channel DAC, microphone amplifier, headphone amplifier, digital sound effects, analog mixing and gain functions. It is interfaced with ESP32-WROVER-E Module over I2S and I2S buses to provide audio processing in hardware independently from the audio application.

Automatic Upload

  Install three jumpers on this header to enable automatic loading of application to the ESP32. Install all jumpers together on all three headers. Remove all jumpers after upload is complete.

Function Press Keys

  Two key labeled Rec and Mode. They are routed to ESP32-WROVER-E Module and intended for developing and testing a UI for audio applications using dedicated API.

USB-UART Bridge Chip

  A single chip USB-UART bridge provides up to 1 Mbps transfers rate.

USB-UART Port

  Functions as the communication interface between a PC and the ESP32 module.

USB Power Port

  Provides the power supply for the board.

Standby / Charging LEDs

  The Standby green LED indicates that power has been applied to the Micro USB Port. The Charging red LED indicates that a battery connected to the Battery Socket is being charged.

Battery Socket

  Two pins socket to connect a single cell Li-ion battery.

  Note

  Please verify if polarity on the battery plug matches polarity of the socket as marked on the board’s soldermask besides the socket.

Battery Charger Chip

  Constant current & constant voltage linear charger for single cell lithium-ion batteries AP5056. Used for charging of a battery connected to the Battery Socket over the Micro USB Port.

Power On LED

  Red LED indicating that Power On Switch is turned on.

  Note

  The Power On Switch does not affect / disconnect the Li-ion battery charging.

Power Switch

  Power on/off knob: toggling it to the left powers the board on; toggling it to the right powers the board off.

###### Hardware Setup Options

There are a couple of options to change the hardware configuration of the ESP32-LyraT board. The options are selectable with the Function DIP Switch.

Enable MicroSD Card in 1-wire Mode

DIP SW | Position
--- | ---
1 | OFF
2 | OFF
3 | OFF
4 | OFF
5 | OFF
6 | OFF
7 | OFF 1
8 | n/a

1. AUX Input detection may be enabled by toggling the DIP SW 7 ON. Note that the AUX Input signal pin should not be be plugged in when the system powers up. Otherwise the ESP32 may not be able to boot correctly.

In this mode:

- JTAG functionality is not available

- Vol- touch button is available for use with the API

Enable MicroSD Card in 4-wire Mode

DIP SW | Position
--- | ---
1 | ON
2 | ON
3 | OFF
4 | OFF
5 | OFF
6 | OFF
7 | OFF
8 | n/a

In this mode:

- JTAG functionality is not available

- Vol- touch button is not available for use with the API

- AUX Input detection from the API is not available

Enable JTAG

DIP SW | Position
--- | ---
1 | OFF
2 | OFF
3 | ON
4 | ON
5 | ON
6 | ON
7 | ON
8 | n/a

In this mode:

- MicroSD Card functionality is not available, remove the card from the slot

- Vol- touch button is not available for use with the API

- AUX Input detection from the API is not available

Using Automatic Upload

Entering of the ESP32 into upload mode may be done in two ways:

- Manually by pressing both Boot and RST keys and then releasing first RST and then Boot key.

- Automatically by software performing the upload. The software is using DTR and RTS signals of the serial interface to control states of EN, IO0 and IO2 pins of the ESP32. This functionality is enabled by installing jumpers in three headers JP23, JP24 and JP25. For details see ESP32 LyraT V4.3 schematic. Remove all jumpers after upload is complete.

###### Allocation of ESP32 Pins

Several pins ESP32 module are allocated to the on board hardware. Some of them, like GPIO0 or GPIO2, have multiple functions. Please refer to the table below or ESP32 LyraT V4.3 schematic for specific details.

GPIO Pin | Type | Function Definition
--- | --- | ---
SENSOR_VP | I | Audio Rec (PB)
SENSOR_VN | I | Audio Mode (PB)
IO32 | I/O | Audio Set (TP)
IO33 | I/O | Audio Play (TP)
IO27 | I/O | Audio Vol+ (TP)
IO13 | I/O | JTAG MTCK, MicroSD D3, Audio Vol- (TP)
IO14 | I/O | JTAG MTMS, MicroSD CLK
IO12 | I/O | JTAG MTDI, MicroSD D2, Aux signal detect
IO15 | I/O | JTAG MTDO, MicroSD CMD
IO2 | I/O | Automatic Upload, MicroSD D0
IO4 | I/O | MicroSD D1
IO34 | I | MicroSD insert detect
IO0 | I/O | Automatic Upload, I2S MCLK
IO5 | I/O | I2S SCLK
IO25 | I/O | I2S LRCK
IO26 | I/O | I2S DSDIN
IO35 | I | I2S ASDOUT
IO19 | I/O | Headphone jack insert detect
IO22 | I/O | Green LED indicator
IO21 | I/O | PA Enable output
IO18 | I/O | I2C SDA
IO23 | I/O | I2C SCL

- (TP) - touch pad

- (PB) - push button

###### Pinout of Extension Headers

There are several pin headers available to connect external components, check the state of particular signal bus or debug operation of ESP32. Note that some signals are shared, see section Allocation of ESP32 Pins for details.

UART Header / JP2

| Header Pin
--- | ---
1 | 3.3V
2 | TX
3 | RX
4 | GND

I2S Header / JP4

| I2C Header Pin | ESP32 Pin
--- | --- | ---
1 | MCLK | GPI0
2 | SCLK | GPIO5
1 | LRCK | GPIO25
2 | DSDIN | GPIO26
3 | ASDOUT | GPIO35
3 | GND | GND

I2C Header / JP5

| I2C Header Pin | ESP32 Pin
--- | --- | ---
1 | SCL | GPIO23
2 | SDA | GPIO18
3 | GND | GND

JTAG Header / JP7

| ESP32 Pin | JTAG Signal
--- | --- | ---
1 | MTDO / GPIO15 | TDO
2 | MTCK / GPIO13 | TCK
3 | MTDI / GPIO12 | TDI
4 | MTMS / GPIO14 | TMS

###### Notes of Power Distribution

The board features quite extensive power distribution system. It provides independent power supplies to all critical components. This should reduce noise in the audio signal from digital components and improve overall performance of the components.

Power Supply Separation

The main power supply is 5V and provided by a USB. The secondary power supply is 3.7V and provided by an optional battery. The USB power itself is fed with a dedicated cable, separate from a USB cable used for an application upload. To further reduce noise from the USB, the battery may be used instead of the USB.

ESP32 LyraT V4.3 - Power Supply Separation

Three Dedicated LDOs

ESP32 Module

To provide enough current the ESP32, the development board adopts LD1117S33CTR LDO capable to supply the maximum output current of 800mA.

ESP32 LyraT V4.3 - Dedicated LDO for the ESP32 Module

MicroSD Card and Audio Codec

Two separate LDOs are provided for the MicorSD Card and the Audio Codec. Both circuits have similar design that includes an inductor and double decoupling capacitors on both the input and output of the LDO.

ESP32 LyraT V4.3 - Dedicated LDO for the MicroSD Card

Separate Power Feed for the PAs

The audio amplifier unit features two NS4150 that require a large power supply for driving external speakers with the maximum output power of 3W. The power is supplied directly to both PAs from the battery or the USB. The development board adds a set of LC circuits at the front of the PA power supply, where L uses 1.5A magnetic beads and C uses 10uF aluminum electrolytic capacitors, to effectively filter out power crosstalk.

ESP32 LyraT V4.3 - Power Supply for the PAs

###### Selecting of the Audio Output

The development board uses two mono Class D amplifier ICs, model number NS4150 with maximum output power of 3W and operating voltage from 3.0V to 5.25V.

The audio input source is the digital-to-analog converter (DAC) output of the ES8388. Audio output supports two external speakers.

An optional audio output is a pair of headphones feed from the same DACs as the amplifier ICs.

To switch between using headphones and speakers, the board provides a digital input signal to detect when a headphone jack is inserted and a digital output signal to enable or disable the amplifier ICs. In other words selection between speakers and headphones is under software control instead of using mechanical contacts that would disconnect speakers once a headphone jack is inserted.

##### Other Versions of LyraT

- ESP32-LyraT V4.2 Getting Started Guide

- ESP32-LyraT V4 Getting Started Guide

##### Related Documents

- ESP32 LyraT V4.3 schematic (PDF)

- ESP32-LyraT V4.3 Getting Started Guide

- ESP32 Datasheet (PDF)

- ESP32-WROVER-E Datasheet (PDF)

- JTAG Debugging

#### ESP32-LyraT V4.2 Getting Started Guide

This guide provides users with functional descriptions, configuration options for ESP32-LyraT V4.2 audio development board, as well as how to get started with the ESP32-LyraT board.

The ESP32-LyraT development board is a hardware platform designed for the dual-core ESP32 audio applications, e.g., Wi-Fi or BT audio speakers, speech-based remote controllers, smart-home appliances with audio functionality(ies), etc.

If you like to start using this board right now, go directly to section Start Application Development.

##### What You Need

- 1 × ESP32 LyraT V4.2 board

- 2 × Speaker or headphones with a 3.5 mm jack. If you use a speaker, it is recommended to choose one no more than 3 watts, and JST PH 2.0 2-Pin plugs are needed. In case you do not have this type of plug it is also fine to use Dupont female jumper wires during development.

- 2 x Micro-USB 2.0 cables, Type A to Micro B

- 1 × PC loaded with Windows, Linux or Mac OS

###### Overview

The ESP32-LyraT V4.2 is an audio development board produced by Espressif built around ESP32. It is intended for audio applications, by providing hardware for audio processing and additional RAM on top of what is already onboard of the ESP32 chip. The specific hardware includes:

- ESP32-WROVER Module*

- Audio Codec Chip

- Dual Microphones on board

- Headphone input

- 2 x 3-watt Speaker output

- Dual Auxiliary Input

- MicroSD Card slot (1 line or 4 lines)

- Six buttons (2 physical buttons and 4 touch buttons)

- JTAG header

- Integrated USB-UART Bridge Chip

- Li-ion Battery-Charge Management

The superscript * indicates that the product is in EOL status. The same applies below.

The block diagram below presents main components of the ESP32-LyraT and interconnections between components.

ESP32-LyraT Block Diagram

###### Functional Description

The following list and figure describe key components, interfaces and controls of the ESP32-LyraT board.

ESP32-WROVER Module*

  The ESP32-WROVER module* contains ESP32 chip to provide Wi-Fi / BT connectivity and data processing power as well as integrates 32 Mbit SPI flash and 32 Mbit PSRAM for flexible data storage.

Green and Red LEDs

  Two general purpose LEDs controlled by ESP32-WROVER Module* to indicate certain operation states of the audio application using dedicated API.

Function DIP Switch

  Used to configure function of GPIO12 to GPIO15 pins that are shared between devices, primarily between JTAG Header and MicroSD Card. By default, the MicroSD Card is enabled with all switches in OFF position. To enable the JTAG Header instead, switches in positions 3, 4, 5 and 6 should be put ON. If JTAG is not used and MicroSD Card is operated in the one-line mode, then GPIO12 and GPIO13 may be assigned to other functions. Please refer to ESP32 LyraT V4.2 schematic for more details.

JTAG Header

  Provides access to the JTAG interface of ESP32-WROVER Module*. It may be used for debugging, application upload, as well as implementing several other functions, e.g., Application Level Tracing. See JTAG Header / JP7 for pinout details. Before using JTAG signals to the header, Function DIP Switch should be enabled. Please note that when JTAG is in operation, MicroSD Card cannot be used and should be disconnected because some of JTAG signals are shared by both devices.

UART Header

  Serial port: provides access to the serial TX/RX signals between ESP32-WROVER Module* and USB-UART Bridge Chip.

I2C Header

  Provides access to the I2C interface. Both ESP32-WROVER Module* and Audio Codec Chip are connected to this interface. See I2C Header / JP5 for pinout details.

MicroSD Card

  The development board supports a MicroSD card in SPI/1-bit/4-bit modes, and can store or play audio files in the MicroSD card. See MicroSD Card / J5 for pinout details. Note that JTAG cannot be used and should be disconnected by setting Function DIP Switch when MicroSD Card is in operation, because some of signals are shared by both devices.

I2S Header

  Provides access to the I2S interface. Both ESP32-WROVER Module* and Audio Codec Chip are connected to this interface. See I2S Header / JP4 for pinout details.

Left Microphone

  Onboard microphone connected to IN1 of the Audio Codec Chip.

AUX Input

  Auxiliary input socket connected to IN2 (left and right channel) of the Audio Codec Chip. Use a 3.5 mm stereo jack to connect to this socket.

Headphone Output

  Output socket to connect headphones with a 3.5 mm stereo jack.

ESP32-LyraT V4.2 Board Layout

Right Microphone

  Onboard microphone connected to IN1 of the Audio Codec Chip.

Left Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

Right Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

PA Chip

  A power amplifier used to amplify stereo audio signal from the Audio Codec Chip for driving two speakers.

Boot/Reset Press Keys

  Boot: holding down the Boot button and momentarily pressing the Reset button initiates the firmware upload mode. Then user can upload firmware through the serial port. Reset: pressing this button alone resets the system.

Touch Pad Buttons

  Four touch pads labeled Play, Sel, Vol+ and Vol-. They are routed to ESP32-WROVER Module* and intended for development and testing of a UI for audio applications using dedicated API.

Audio Codec Chip

  The Audio Codec Chip, ES8388, is a low power stereo audio codec with a headphone amplifier. It consists of 2-channel ADC, 2-channel DAC, microphone amplifier, headphone amplifier, digital sound effects, analog mixing and gain functions. It is interfaced with ESP32-WROVER Module* over I2S and I2S buses to provide audio processing in hardware independently from the audio application.

EN Header

  Install a jumper on this header to enable automatic loading of application to the ESP32. Install or remove jumpers together on both IO0 and EN headers.

IO0 Header

  Install a jumper on this header to enable automatic loading of application to the ESP32. Install or remove jumpers together on both IO0 and EN headers.

Function Press Keys

  Two key labeled Rec and Mode. They are routed to ESP32-WROVER Module* and intended for developing and testing a UI for audio applications using dedicated API.

USB-UART Bridge Chip

  A single chip USB-UART bridge provides up to 1 Mbps transfers rate.

USB-UART Port

  Functions as the communication interface between a PC and the ESP32 module.

USB Power Port

  Provides the power supply for the board.

Standby / Charging LEDs

  The Standby green LED indicates that power has been applied to the Micro USB Port. The Charging red LED indicates that a battery connected to the Battery Socket is being charged.

Battery Charger Chip

  Constant current & constant voltage linear charger for single cell lithium-ion batteries AP5056. Used for charging of a battery connected to the Battery Socket over the Micro USB Port.

Power On Switch

  Power on/off knob: toggling it to the left powers the board on; toggling it to the right powers the board off.

Battery Socket

  Two pins socket to connect a single cell Li-ion battery.

Power On LED

  Red LED indicating that Power On Switch is turned on.

  Note

  The Power On Switch does not affect / disconnect the Li-ion battery charging.

###### Hardware Setup Options

There are a couple of options to change the hardware configuration of the ESP32-LyraT board. The options are selectable with the Function DIP Switch.

Enable MicroSD Card in 1-wire Mode

DIP SW | Position
--- | ---
1 | OFF
2 | OFF
3 | OFF
4 | OFF
5 | OFF
6 | OFF
7 | OFF 1
8 | n/a

1. AUX Input detection may be enabled by toggling the DIP SW 7 ON

In this mode:

- JTAG functionality is not available

- Vol- touch button is available for use with the API

Enable MicroSD Card in 4-wire Mode

DIP SW | Position
--- | ---
1 | ON
2 | ON
3 | OFF
4 | OFF
5 | OFF
6 | OFF
7 | OFF
8 | n/a

In this mode:

- JTAG functionality is not available

- Vol- touch button is not available for use with the API

- AUX Input detection from the API is not available

Enable JTAG

DIP SW | Position
--- | ---
1 | OFF
2 | OFF
3 | ON
4 | ON
5 | ON
6 | ON
7 | ON
8 | n/a

In this mode:

- MicroSD Card functionality is not available, remove the card from the slot

- Vol- touch button is not available for use with the API

- AUX Input detection from the API is not available

###### Allocation of ESP32 Pins

Several pins / terminals of ESP32 modules are allocated to the on board hardware. Some of them, like GPIO0 or GPIO2, have multiple functions. Please refer to the tables below or ESP32 LyraT V4.2 schematic for specific details.

Red / Green LEDs

| ESP32 Pin | LED Color
--- | --- | ---
1 | GPIO19 | Red LED
2 | GPIO22 | Green LED

Touch Pads

| ESP32 Pin | Touch Pad Function
--- | --- | ---
1 | GPIO33 | Play
2 | GPIO32 | Set
3 | GPIO13 | Vol- 1
4 | GPIO27 | Vol+

1. Vol- function is not available if JTAG is used. It is also not available for the MicroSD Card configured to operate in 4-wire mode.

MicroSD Card / J5

| ESP32 Pin | MicroSD Signal
--- | --- | ---
1 | MTDI / GPIO12 | DATA2
2 | MTCK / GPIO13 | CD / DATA3
3 | MTDO / GPIO15 | CMD
4 | MTMS / GPIO14 | CLK
5 | GPIO2 | DATA0
6 | GPIO4 | DATA1
7 | GPIO21 | CD

UART Header / JP2

| Header Pin
--- | ---
1 | 3.3V
2 | TX
3 | RX
4 | GND

EN and IO0 Headers / JP23 and J24

| ESP32 Pin | Header Pin
--- | --- | ---
1 | n/a | EN_Auto
2 | EN | EN

| ESP32 Pin | Header Pin
--- | --- | ---
1 | n/a | IO0_Auto
2 | GPIO0 | IO0

I2S Header / JP4

| I2C Header Pin | ESP32 Pin
--- | --- | ---
1 | MCLK | GPI0
2 | SCLK | GPIO5
1 | LRCK | GPIO25
2 | DSDIN | GPIO26
3 | ASDOUT | GPIO35
3 | GND | GND

I2C Header / JP5

| I2C Header Pin | ESP32 Pin
--- | --- | ---
1 | SCL | GPIO23
2 | SDA | GPIO18
3 | GND | GND

JTAG Header / JP7

| ESP32 Pin | JTAG Signal
--- | --- | ---
1 | MTDO / GPIO15 | TDO
2 | MTCK / GPIO13 | TCK
3 | MTDI / GPIO12 | TDI
4 | MTMS / GPIO14 | TMS

Function DIP Switch / JP8

| Switch OFF | Switch ON
--- | --- | ---
1 | GPIO12 not allocated | MicroSD Card 4-wire
2 | Touch Vol- enabled | MicroSD Card 4-wire
3 | MicroSD Card | JTAG
4 | MicroSD Card | JTAG
5 | MicroSD Card | JTAG
6 | MicroSD Card | JTAG
7 | MicroSD Card 4-wire | AUX IN detect 1
8 | not used | not used

1. The AUX Input signal pin should not be be plugged in when the system powers up. Otherwise the ESP32 may not be able to boot correctly.

##### Start Application Development

Before powering up the ESP32-LyraT, please make sure that the board has been received in good condition with no obvious signs of damage.

###### Initial Setup

Prepare the board for loading of the first sample application:

1. Install jumpers on IO0 and EN headers to enable automatic application upload. If there are no jumpers then upload may be triggered using Boot / RST buttons.

2. Connect speakers to the Right and Left Speaker Output.Connecting headphones to the Headphone Output is an option.

3. Plug in the Micro-USB cables to the PC and to both USB ports of the ESP32 LyraT.

4. The Standby LED (green) should turn on. Assuming that a battery is not connected, the Charging LED will blink every couple of seconds.

5. Toggle left the Power On Switch.

6. The red Power On LED should turn on.

If this is what you see on the LEDs, the board should be ready for application upload. Now prepare the PC by loading and configuring development tools what is discussed in the next section.

###### Develop Applications

Once the board is initially set up and checked, you can start preparing the development tools. The Section Installation Step by Step will walk you through the following steps:

- Set up ESP-IDF to get a common development framework for the ESP32 (and ESP32-S2) chips in C language;

- Get ESP-ADF to install the API specific to audio applications;

- Set up env to make the framework aware of the audio specific API;

- Start a Project that will provide a sample audio application for the board;

- Connect Your Device to prepare the application for loading;

- Build the Project to finally run the application and play some music.

##### Related Documents

- ESP32 LyraT V4.2 schematic (PDF)

- ESP32 Datasheet (PDF)

- JTAG Debugging

- ESP32-LyraT V4 Getting Started Guide

#### ESP32-LyraT V4 Getting Started Guide

This guide provide users with functional descriptions, configuration options for ESP32-LyraT V4 audio development board, as well as how to get started with ESP32-LyraT board.

The ESP32-LyraT development board is a hardware platform specifically designed for the dual-core ESP32 audio applications, e.g., Wi-Fi or BT audio speakers, speech-based remote controllers, smart-home appliances with audio functionality(ies), etc.

If you like to start using this board right now, go directly to section Start Application Development.

##### What You Need

- 1 × ESP32-LyraT V4 board

- 2 × Speaker or headphones with a 3.5 mm jack. If you use a speaker, it is recommended to choose one no more than 3 watts, and JST PH 2.0 2-Pin plugs are needed. In case you do not have this type of plug it is also fine to use Dupont female jumper wires during development.

- 1 × Micro USB 2.0 Cable, Type A to Micro B

- 1 × PC loaded with Windows, Linux or Mac OS

###### Overview

The ESP32-LyraT V4 is an audio development board produced by Espressif built around ESP32. It is intended for audio applications, by providing hardware for audio processing and additional RAM on top of what is already onboard of the ESP32 chip. The specific hardware includes:

- ESP32-WROVER Module*

- Audio Codec Chip

- Dual Microphones on board

- Headphone input

- 2 x 3 Watt Speaker output

- Dual Auxiliary Input

- MicroSD Card slot (1 line or 4 lines)

- 6 buttons (2 physical buttons and 4 touch buttons)

- JTAG header

- Integrated USB-UART Bridge Chip

- Li-ion Battery-Charge Management

The superscript * indicates that the product is in EOL status. The same applies below.

The block diagram below presents main components of the ESP32-LyraT and interconnections between components.

ESP32-LyraT block diagram

###### Functional Description

The following list and figure below describe key components, interfaces and controls of the ESP32-LyraT board.

ESP32-WROVER Module*

  The ESP32-WROVER* module contains ESP32 chip to provide Wi-Fi / BT connectivity and data processing power as well as integrates 32 Mbit SPI flash and 32 Mbit PSRAM for flexible data storage.

Green and Red LEDs

  Two general purpose LEDs controlled by ESP32-WROVER Module* to indicate certain operation states of the audio application using dedicated API.

Function DIP Switch

  Used to configure function of GPIO12 to GPIO15 pins that are shared between devices, primarily between JTAG Header and MicroSD Card. By default MicroSD Card is enabled with all switches in OFF position. To enable JTAG Header instead, switches in positions 3, 4, 5 and 6 should be put ON. If JTAG is not used and MicroSD Card is operated in one-line mode, then GPIO12 and GPIO13 may be assigned to other functions. Please refer to ESP32 LyraT V4 schematic for more details.

JTAG Header

  Provides access to the JTAG interface of ESP32-WROVER Module*. May be used for debugging, application upload, as well as implementing several other functions, e.g., Application Level Tracing. See JTAG Header / JP7 for pinout details. Before using JTAG signals to the header, Function DIP Switch should be enabled. Please note that when JTAG is in operation, MicroSD Card cannot be used and should be disconnected because some of JTAG signals are shared by both devices.

UART Header

  Serial port provides access to the serial TX/RX signals between ESP32-WROVER Module* and USB-UART Bridge Chip.

I2C Header

  Provides access to the I2C interface. Both ESP32-WROVER Module* and Audio Codec Chip are connected to this interface. See I2C Header / JP5 for pinout details.

MicroSD Card

  The development board supports a MicroSD card in SPI/1-bit/4-bit modes, and can store or play audio files in the MicroSD card. See MicroSD Card / J5 for pinout details. Note that JTAG cannot be used and should be disconnected by setting Function DIP Switch when MicroSD Card is in operation, because some of the signals are shared by both devices.

I2S Header

  Provides access to the I2S interface. Both ESP32-WROVER Module* and Audio Codec Chip are connected to this interface. See I2S Header / JP4 for pinout details.

Left Microphone

  Onboard microphone connected to IN1 of the Audio Codec Chip.

AUX Input

  Auxiliary input socket connected to IN2 (left and right channels) of the Audio Codec Chip. Use a 3.5 mm stereo jack to connect to this socket.

Headphone Output

  Output socket to connect headphones with a 3.5 mm stereo jack.

ESP32 LyraT V4 board layout

Right Microphone

  Onboard microphone connected to IN1 of the Audio Codec Chip.

Left Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

Right Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

PA Chip

  A power amplifier used to amplify stereo audio signal from the Audio Codec Chip for driving two speakers.

Boot/Reset Press Keys

  Boot: holding down the Boot button and momentarily pressing the Reset button initiates the firmware upload mode. Then user can upload firmware through the serial port. Reset: pressing this button alone resets the system.

Touch Pad Buttons

  Four touch pads labeled Play, Sel, Vol+ and Vol-. They are routed to ESP32-WROVER Module* and intended for development and testing of a UI for audio applications using dedicated API.

Audio Codec Chip

  The Audio Codec Chip, ES8388, is a low-power stereo audio codec with headphone amplifier. It consists of 2-channel ADC, 2-channel DAC, microphone amplifier, headphone amplifier, digital sound effects, analog mixing and gain functions. It is interfaced with ESP32-WROVER Module* over I2S and I2S buses to provide audio processing in hardware independently from the audio application.

Function Press Keys

  Two key labeled Rec and Mode. They are routed to ESP32-WROVER Module* and intended for developing and testing a UI for audio applications using dedicated API.

USB-UART Bridge Chip

  A single chip USB-UART bridge provides up to 1 Mbps transfer rate.

Micro USB Port

  USB interface. It functions as the power supply for the board and the communication interface between a PC and the ESP32 module.

Standby / Charging LEDs

  The Standby green LED indicates that power has been applied to the Micro USB Port. The Charging red LED indicates that a battery connected to the Battery Socket is being charged.

Battery Charger Chip

  Constant current & constant voltage linear charger for single cell lithium-ion batteries AP5056. Used for charging of a battery connected to the Battery Socket over the Micro USB Port.

Power On Switch

  Power on/off knob: toggling it to the left powers the board on; toggling it to the right powers the board off.

Battery Socket

  Two pins socket to connect a single cell Li-ion battery.

Power On LED

  Red LED indicating that Power On Switch is turned on.

  Note

  The Power On Switch does not affect / disconnect the Li-ion battery charging.

###### Hardware Setup Options

There are couple of options to change the hardware configuration of the ESP32-LyraT board. The options are selectable with the Function DIP Switch.

Enable MicroSD Card in 1-wire Mode

DIP SW | Position
--- | ---
1 | OFF
2 | OFF
3 | OFF
4 | OFF
5 | OFF
6 | OFF
7 | OFF 1
8 | n/a

1. AUX Input detection may be enabled by toggling the DIP SW 7 ON

In this mode:

- JTAG functionality is not available

- Vol- touch button is available for use with the API

Enable MicroSD Card in 4-wire Mode

DIP SW | Position
--- | ---
1 | ON
2 | ON
3 | OFF
4 | OFF
5 | OFF
6 | OFF
7 | OFF
8 | n/a

In this mode:

- JTAG functionality is not available

- Vol- touch button is not available for use with the API

- AUX Input detection from the API is not available

Enable JTAG

DIP SW | Position
--- | ---
1 | OFF
2 | OFF
3 | ON
4 | ON
5 | ON
6 | ON
7 | ON
8 | n/a

In this mode:

- MicroSD Card functionality is not available, remove the card from the slot

- Vol- touch button is not available for use with the API

- AUX Input detection from the API is not available

###### Allocation of ESP32 Pins

Several pins / terminals of ESP32 modules are allocated to the onboard hardware. Some of them, like GPIO0 or GPIO2, have multiple functions. Please refer to tables below or ESP32 LyraT V4 schematic for specific details.

Red / Green LEDs

| ESP32 Pin | LED Color
--- | --- | ---
1 | GPIO19 | Red LED
2 | GPIO22 | Green LED

Touch Pads

| ESP32 Pin | Touch Pad Function
--- | --- | ---
1 | GPIO33 | Play
2 | GPIO32 | Set
3 | GPIO13 | Vol- 1
4 | GPIO27 | Vol+

1. Vol- function is not available if JTAG is used. It is also not available for the MicroSD Card configured to operate in 4-wire mode.

MicroSD Card / J5

| ESP32 Pin | MicroSD Signal
--- | --- | ---
1 | MTDI / GPIO12 | DATA2
2 | MTCK / GPIO13 | CD / DATA3
3 | MTDO / GPIO15 | CMD
4 | MTMS / GPIO14 | CLK
5 | GPIO2 | DATA0
6 | GPIO4 | DATA1
7 | GPIO21 | CD

UART Header / JP2

| Header Pin
--- | ---
1 | 3.3V
2 | TX
3 | RX
4 | GND

I2S Header / JP4

| I2C Header Pin | ESP32 Pin
--- | --- | ---
1 | MCLK | GPI0
2 | SCLK | GPIO5
1 | LRCK | GPIO25
2 | DSDIN | GPIO26
3 | ASDOUT | GPIO35
3 | GND | GND

I2C Header / JP5

| I2C Header Pin | ESP32 Pin
--- | --- | ---
1 | SCL | GPIO23
2 | SDA | GPIO18
3 | GND | GND

JTAG Header / JP7

| ESP32 Pin | JTAG Signal
--- | --- | ---
1 | MTDO / GPIO15 | TDO
2 | MTCK / GPIO13 | TCK
3 | MTDI / GPIO12 | TDI
4 | MTMS / GPIO14 | TMS

Function DIP Switch / JP8

| Switch OFF | Switch ON
--- | --- | ---
1 | GPIO12 not allocated | MicroSD Card 4-wire
2 | Touch Vol- enabled | MicroSD Card 4-wire
3 | MicroSD Card | JTAG
4 | MicroSD Card | JTAG
5 | MicroSD Card | JTAG
6 | MicroSD Card | JTAG
7 | MicroSD Card 4-wire | AUX IN detect 1
8 | not used | not used

1. The AUX Input signal pin should not be plugged in when the system powers up. Otherwise the ESP32 may not be able to boot correctly.

##### Start Application Development

Before powering up the ESP32-LyraT, please make sure that the board has been received in good condition with no obvious signs of damage.

###### Initial Setup

Prepare the board for loading of the first sample application:

1. Connect speakers to the Right and Left Speaker Output. Optionally connect headphones to the Headphone Output.

2. Plug in the Micro-USB cable to the PC and to the Micro USB Port of the ESP32-LyraT.

3. The Standby LED (green) should turn on. Assuming that a battery is not connected, the Charging LED will momentarily blink every couple of seconds.

4. Toggle left the Power On Switch.

5. The red Power On LED should turn on.

If this is what you see on the LEDs, the board should be ready for application upload. Now prepare the PC by loading and configuring development tools what is discussed in the next section.

###### Develop Applications

Once the board is initially set up and checked, you can start preparing the development tools. The Section Installation Step by Step will walk you through the following steps:

- Set up ESP-IDF to get a common development framework for the ESP32 (and ESP32-S2) chips in C language;

- Get ESP-ADF to install the API specific to audio applications;

- Set up env to make the framework aware of the audio specific API;

- Start a Project that will provide a sample audio application for the board;

- Connect Your Device to prepare the application for loading;

- Build the Project to finally run the application and play some music.

##### Related Documents

- ESP32 LyraT V4 schematic (PDF)

- ESP32 Datasheet (PDF)

- JTAG Debugging

#### ESP32-LyraTD-MSC V2.2 Getting Started Guide

[中文]

This guide provides users with functional descriptions, configuration options for ESP32-LyraTD-MSC V2.2 audio development board, as well as how to get started with the ESP32-LyraTD-MSC board.

The ESP32-LyraTD-MSC is a hardware platform designed for smart speakers and AI applications. It supports Acoustic Echo Cancellation (AEC), Automatic Speech Recognition (ASR), Wake-up Interrupt and Voice Interaction.

##### What You Need

- 1 × ESP32-LyraTD-MSC V2.2 board

- 2 x Speaker or headphones with a 3.5 mm jack. If you use a speaker, it is recommended to choose one no more than 3 watts, and JST PH 2.0 2-Pin plugs are needed. In case you do not have this type of plug it is also fine to use Dupont female jumper wires during development.

- 2 x Micro-USB 2.0 cables, Type A to Micro B

- 1 × PC loaded with Windows, Linux or Mac OS

If you like to start using this board right now, go directly to section Start Application Development.

###### Overview

The ESP32-LyraTD-MSC V2.2 is an audio development board produced by Espressif built around ESP32. It is intended for smart speakers and AI applications, by providing hardware for digital signal processing, microphone array and additional RAM on top of what is already onboard of the ESP32 chip.

This audio development board consists of two parts: the upper board (B), which provides a three-microphone array, function keys and LED lights; and the lower board (A), which integrates ESP32-WROVER-E, a MicroSemi Digital Signal Processing (DSP) chip, and a power management module.

ESP32-LyraTD-MSC Side View

The specific hardware includes:

- ESP32-WROVER-E Module

- DSP (Digital Signal Processing) chip

- Three digital Microphones that support far-field voice pick-up

- 2 x 3-watt Speaker output

- Headphone output

- MicroSD Card slot (1 line or 4 lines)

- Individually controlled Twelve LEDs distributed in a circle on the board’s edge

- Six Function Buttons that may be assigned user functions

- Several interface ports: I2S, I2C, SPI and JTAG

- Integrated USB-UART Bridge Chip

- Li-ion Battery-Charge Management

The block diagram below presents main components of the ESP32-LyraTD-MSC and interconnections between components.

ESP32-LyraTD-MSC Block Diagram

###### Components

The following list and figure describe key components, interfaces and controls of the ESP32-LyraTD-MSC used in this guide. This covers just what is needed now. For additional details please refer to schematics provided in Related Documents.

ESP32-WROVER-E Module

  The ESP32-WROVER-E module contains ESP32 chip to provide Wi-Fi / Bluetooth connectivity and data processing power as well as integrates 4 MB external SPI flash and an additional 8 MB PSRAM for flexible data storage.

DSP Chip

  The Digital Signal Processing chip ZL38063 is used for Automatic Speech Recognition (ASR) applications. It captures audio data from an external microphone array and outputs audio signals through its Digital-to-Analog-Converter (DAC) port.

Headphone Output

  Output socket to connect headphones with a 3.5 mm stereo jack.

  Note

  The socket may be used with mobile phone headsets and is compatible with OMPT standard headsets only. It does not work with CTIA headsets. Please refer to Phone connector (audio) on Wikipedia.

Left Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

Right Speaker Output

  Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm / 0.08” pitch.

ESP32-LyraTD-MSC V2.2 Lower Board (A) Components

USB-UART Port

  Functions as the communication interface between a PC and the ESP32-WROVER-E module.

USB Power Port

  Provides the power supply for the board.

Standby / Charging LEDs

  The Standby green LED indicates that power has been applied to the Micro USB Port. The Charging red LED indicates that a battery connected to the Battery Socket is being charged.

Power Switch

  Power on/off knob: toggling it right powers the board on; otherwise powers the board off.

Power On LED

  Red LED indicating that Power Switch is turned on.

ESP32-LyraTD-MSC V2.2 Upper Board (B) Components

Boot/Reset Buttons

  Boot: holding down the Boot button and momentarily pressing the Reset button initiates the firmware upload mode. Then user can upload firmware through the serial port.

  Reset: pressing this button alone resets the system.

##### Start Application Development

Before powering up the ESP32-LyraTD-MSC, please make sure that the board has been received in good condition with no obvious signs of damage. Both the lower A and the upper B board of the ESP32-LyraTD-MSC should be firmly connected together.

###### Initial Setup

Prepare the board for loading of the first sample application:

1. Connect speakers to the Right and Left Speaker Output. Connecting headphones to the Headphone Output is an option.

2. Plug in the Micro-USB cables to the PC and to both USB ports of the ESP32-LyraTD-MSC.

3. The Standby LED (green) should turn on. Assuming that a battery is not connected, the Charging LED (red) will blink every couple of seconds.

4. Toggle right the Power Switch.

5. The red Power On LED should turn on.

If this is what you see on the LEDs, the board should be ready for application upload. Now prepare the PC by loading and configuring development tools what is discussed in the next section.

###### Develop Applications

Once the board is initially set up and checked, you can start preparing the development tools. The Section Installation Step by Step will walk you through the following steps:

- Set up ESP-IDF to get a common development framework for the ESP32 (and ESP32-S2) chips in C language;

- Get ESP-ADF to install the API specific to audio applications;

- Set up env to make the framework aware of the audio specific API;

- Start a Project that will provide a sample audio application for the board;

- Connect Your Device to prepare the application for loading;

- Build the Project to finally run the application and play some music.

##### Revision History

- Changed the integrated module to ESP32-WROVER-E from ESP32-WROVER-B.

##### Other Boards from LyraT Family

- ESP32-LyraT V4.3 Getting Started Guide

- ESP32-LyraT-Mini V1.2 Getting Started Guide

##### Related Documents

- ESP32-LyraTD-MSC V2.2 Schematic Lower Board (A) (PDF)

- ESP32-LyraTD-MSC V2.2 Schematic Upper Board (B) (PDF)

- ESP32 Datasheet (PDF)

- ESP32-WROVER-E Datasheet (PDF)

#### ESP32-Korvo-DU1906

[中文]

This user guide provides information on ESP32-Korvo-DU1906.

ESP32-Korvo-DU1906 (click to enlarge)

The document consists of the following major sections:

- Getting Started: Provides an overview of the ESP32-Korvo-DU1906 and hardware/software setup instructions to get started.

- Start Application Development: Provides more detailed information about the ESP32-Korvo-DU1906’s application development process.

- Related Documents: Gives links to related documentaiton.

##### Getting Started

The core component of ESP32-Korvo-DU1906 includes an ESP32-DU1906 Bluetooth/Wi-Fi audio module, which is able to realize noise reduction, acoustic echo cancellation (AEC), beam formation and detection. ESP32-Korvo-DU1906 integrates power management, Bluetooth/Wi-Fi audio module, Coder-Decoder (CODEC), power amplifier, and etc., supports various functions such as:

- ADC

- Microphone array

- SD card

- Functional buttons

- Indicator lights

- Battery constant-current/constant-voltage linear power management chip

- USB-to-UART conversion

- LCD connector

###### What You Need

- 1 x PC loaded with Windows, Mac OS and Linux (Linux Operating System is recommended)

- 1 x ESP32-Korvo-DU1906

- 2 x Micro USB cables

- 2 x Speaker (4 Ohm, 2.5 W)

###### Overview

The biggest advantage of this development board is the audio chip – ESP32-DU1906, the core processing module, is an powerful AI module integrating Wi-Fi+Bluetooth+Bluetooth Low Energy RF and voice/speech signal processing functions, which can be used in various fields. By providing the leading end-to-end audio solutions, high-efficient integrated AI service capabilities, and an on-device AIOT platform which integrates ends and devices, this board is able to largely reduce the threshold for AI access.

DU1906 is a voice processing flagship chip launched by Baidu. This chip has a highly integrated algorithm, which can solve the industrial needs of real-time processing of far-field array signals, and high-precision voice wake-up and real-time monitoring with ultra-low error occurs simultaneously on this single one chip.

The block diagram below presents main components of the ESP32-Korvo-DU1906 and interconnections between components.

ESP32-Korvo-DU1906 Block Diagram (click to enlarge)

###### Description of Components

The following list and figure describe key components, interfaces and controls of the ESP32-Korvo-DU1906 used in this guide. This covers just what is needed now. For additional details please refer to schematics provided in Related Documents.

ESP32-Korvo-DU1906 Components (click to enlarge)

Key Componenet | Description
--- | ---
ESP32-DU1906 | This is a powerful, general-purpose, Wi-Fi/Bluetooth audio communication module, targeting a wide variety of applications ranging from low-power sensor networks to the most demanding tasks, such as voice encoding/decoding, music streaming and running voice assistant client SDK.
DIP Connector for SPI LCD | ESP32-Korvo-DU1906 has a 2.54 mm pitch connector to connect SPI LCD.
Audio ADC (Audio Analog-to-Digital Converter) | ESP32-Korvo-DU1906 includes two ES7243 high-efficiency ADCs, with one for the collection of Audio PA outputs, and another for the collection of Line-in outputs. Both ADCs can be used for AEC.
Line-in/out Connector (Earphone Jacks) | The two earphone jacks are used to connect to Line-out outputs of Audio DAC and Line-in inputs of Audio ADC respectively. When a device is plugged in the Line-out earphone jack of Audio DAC, the Audio PA on the ESP32-Korvo-DU1906 will be turned off.
Speaker Connector | Output sockets to connect two 4-ohm speakers to provide stereo sound via digital Audio PA.
Audio DAC (Audio Digital-to-Analog Converter) | ES7148 Stereo DAC is able to convert digital signals into analog audio outputs.
Audio PA (Digital Audio Power Amplifier) | TAS5805M is a high-efficiency stereo closed-loop D-type amplifier with low power dissipation and rich sound. It can convert audio digital signals into high-power analog audio outputs and transmit them to external speakers for playback. When the Line-out earphone jack of the audio DAC plugged into the device, the Digital Audio PA on the ESP32-Korvo-DU1906 will be turned off.
Battery Connector | Connect a battery.
Battery Charger | AP5056, a constant-current/constant-voltage linear power management chip, can be used for charging management to a single lithium-ion battery.
PWR Slide Switch | Power switch for the board, turn on/off the power supply.
USB to UART | CP2102N supports USB-to-UART conversion for easy download and debugging of software.
DBG USB (Debugging USB) | USB communication between PC and ESP32-DU1906 module.
PWR USB (Power supply USB) | Provide power supply for the whole system. It is recommended that the system be connected to an at least 5 V / 2 A power adapter for sufficient current supply.
Charging LEDs | Indicating battery state. When a battery is connected, BAT_CHRG LED will turn red (indicating the battery is charging), then BAT_STBY LED will turn green (indicating the charging is completed). If there is no battery connected, the BAT_CHRG and BAT_STBY LEDs will be red and green respectively by default.
Power on LEDs | Indicating power state. The two LEDs (SYS_3V3, SYS_5) will turn red when the board is powered on.
Buttons | ESP32-Korvo-DU1906 has four functional buttons, one Reset button and one Boot button.
SD Card Slot | Connect a standard TF card.
ESP_I2C Connector/DSP_I2C Connnector | Two sets of reserved I2C debugging interfaces for users to debug.
Mic | ESP32-Korvo-DU1906 has three on-board digital microphones. The pickup holes of the three microphones are distributed in equilateral pyramid shape with distances of 60 mm in between. Together with DSP, the Microphone Array is able to realize noise reduction, AEC, beam formation and detection.
IR TX/RX (Infrared Transmitter/Receiver) | ESP32-Korvo-DU1906 has one infrared transmitter and one infrared receiver, which can be used together with the remote control module of ESP32.
FPC Connector for Mic | ESP32-Korvo-DU1906 has two FPC connectors to connect the SPI LCD screen and external microphone arrays.
RGB LED | ESP32-Korvo-DU1906 has two RGB LEDs for users that can be configured as status behavior indicator.
Slide Switch for Mic | ESP32-Korvo-DU1906 has a reserved interface for an external Microphone Array sub-board. This switch needs to be toggled to OFF when using an external Microphone Array sub-board, and needs to be toggled to ON when using the on-board Microphone Array.

##### Start Application Development

Before powering up the ESP32-Korvo-DU1906, please make sure that the board has been received in good condition with no obvious signs of damage.

###### Initial Setup

Prepare the board for loading of the first sample application:

1. Connect 4-ohm speakers to the two Speaker Connectors. Connecting earphones to the Line-out Connector is an option.

2. Plug in the Micro-USB cables to the PC and to both USB connectors of the ESP32-Korvo-DU1906.

3. Assuming that a battery is connected, the Charging LED (red) will keep the lights on.

4. Toggle left the PWR Slide Switch.

5. The red Power On LED should turn on.

If this is what you see on the LEDs, the board should be ready for application upload. Now prepare the PC by loading and configuring development tools what is discussed in the next section.

###### Develop Applications

Once the board is initially set up and checked, you can start preparing the development tools. The Section Development Boards will walk you through the following steps:

- Set up ESP-IDF to get a common development framework for the ESP32 (and ESP32-S2) chips in C language;

- Get ESP-ADF to install the API specific to audio applications;

- Set up env to make the framework aware of the audio specific API;

- Start a Project that will provide a sample audio application for the board;

- Connect Your Device to prepare the application for loading;

- Build the Project to finally run the application and play some music.

##### Other Related Boards

- ESP32-LyraT V4.3 Getting Started Guide

- ESP32-LyraT-Mini V1.2 Getting Started Guide

- ESP32-LyraTD-MSC V2.2 Getting Started Guide

##### Contents and Packaging

###### Retail orders

If you order one or several samples, each board will come in a plastic package or other package chosen by the retailer.

For retail orders, please go to https://www.espressif.com/zh-hans/products/devkits/esp32-korvo-du1906.

##### Related Documents

- ESP32-Korvo-DU1906 Schematic (PDF)

- ESP32 Datasheet (PDF)

#### ESP32-S3-Korvo-2 V3.0

[中文]

This user guide will help you get started with ESP32-S3-Korvo-2 V3.0 and will also provide more in-depth information.

The ESP32-S3-Korvo-2 is a multimedia development board based on the ESP32-S3 chip. It is equipped with a two-microphone array which is suitable for voice recognition and near/far-field voice wake-up applications. The board integrates multiple peripherals such as LCD, camera, and microSD card. It also supports JPEG video stream processing. With all of its outstanding features, the board is an ideal choice for the development of low-cost and low-power network-connected audio and video products.

ESP32-S3-Korvo-2 V3.0 with ESP32-S3-WROOM-1 module

This board mainly consists of the following parts:

- Main board: ESP32-S3-Korvo-2

- LCD extension board: ESP32-S3-Korvo-2-LCD

- Camera

This document is mostly dedicated to the main board. For detailed information on other parts, click the links above.

The document consists of the following sections:

- Getting started: Overview of the board and hardware/software setup instructions to get started.

- Hardware Reference: More detailed information about the board’s hardware.

- Hardware Revision Details: Hardware revision history, known issues, and links to user guides for previous versions (if any) of the board.

- Related Documents: Links to related documentation.

##### Getting Started

This section provides a brief introduction of ESP32-S3-Korvo-2 V3.0, instructions on how to do the initial hardware setup and how to flash firmware onto it.

###### Description of Components

ESP32-S3-Korvo-2 V3.0 (click to enlarge)

The key components of the board are described in a clockwise direction.

Key Component | Description
--- | ---
ESP32-S3-WROOM-1 Module | The ESP32-S3-WROOM-1 is a powerful, generic Wi-Fi + Bluetooth LE MCU module that is built around the ESP32-S3 series of SoCs. On top of a rich set of peripherals, the acceleration for neural network computing and signal processing workloads provided by the SoC make the modules an ideal choice for a wide variety of application scenarios related to AI and Artificial Intelligence of Things (AIoT), such as wake word detection, speech commands recognition, face detection and recognition, smart home, smart appliances, smart control panel, smart speaker, etc.
Left Microphone | Onboard microphone connected to ADC.
Audio ADC Chip | ES7210 is a high-performance, low-power 4-channel audio analog-to-digital converter for microphone array applications. It is very suitable for music and speech applications. In addition, ES7210 can also be used to collect acoustic echo cancellation (AEC) echo reference signals.
Audio Codec Chip | The audio codec chip, ES8311, is a low-power mono audio codec. It consists of 1-channel ADC, 1-channel DAC, low noise pre-amplifier, headphone driver, digital sound effects, analog mixing, and gain functions. It is interfaced with ESP32-S3-WROOM-1 module over I2S and I2C buses to provide audio processing in hardware independently from the audio application.
Audio PA Chip | NS4150 is an EMI, 3 W mono Class D audio power amplifier, amplifying audio signals from audio codec chips to drive speakers.
Right Microphone | Onboard microphone connected to ADC.
Speaker Output Port | Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm/0.08” pitch.
USB-to-UART Bridge Chip | A single chip USB-UART bridge CP2102N provides up to 3 Mbps transfer rates for software download and debugging.
USB-to-UART Port | Functions as the communication interface between a PC and the ESP32-S3-WROOM-1 module.
USB Power Port | Provides power to the board. It is recommended to use at least 5V/2A power adapter to ensure a stable power supply.
Battery Socket | Two pins socket to connect a single cell Li-ion battery.
Power Switch | Power on/off knob: toggling it down powers the board on; toggling it up powers the board off.
Battery Charger | AP5056 is a constant current and constant voltage linear charger for single cell lithium-ion batteries. Used for charging of a battery connected to the Battery Socket over the Micro USB Port.
Function Press Keys | Six press keys labeled REC, MUTE, PLAY, SET, VOL- and VOL+. They are routed to ESP32-S3-WROOM-1 module and intended for development and testing of a UI for audio applications using a dedicated API.
Boot/Reset Press Keys | Boot: holding down the Boot key and momentarily pressing the Reset key initiates the firmware upload mode. Then you can upload firmware through the serial port. Reset: pressing this button alone resets the system.
MicroSD Slot | The development board supports a microSD card in 1-bit mode, and can store or play audio files in the microSD card.
LCD Connector | A FPC connector with 0.5 mm pitch to connect to the LCD extension board.
System LEDs | Two general-purpose LEDs (green and red) controlled by ESP32-S3-WROOM-1 module to indicate certain operation states of the audio application using dedicated API.
Camera Connector | An external camera module that can be connected to the development board with the connector to transmit images.

###### Start Application Development

Before powering up your board, please make sure that it is in good condition with no obvious signs of damage.

Required Hardware

- 1 x ESP32-S3-Korvo-2 V3.0

- 1 x Speaker

- 2 x USB 2.0 cable (Standard-A to Micro-B)

- 1 x Computer running Windows, Linux, or macOS

Note

Be sure to use an appropriate USB cable. Some cables are for charging only and do not provide the needed data lines nor work for programming the boards.

Optional Hardware

- 1 x MicroSD card

- 1 x Li-ion battery

Note

Be sure to use a Li-ion battery that has a built-in protection circuit.

Hardware Setup

1. Connect the speaker to the Speaker Output.

2. Plug in the USB cables to the PC and to both USB ports of the board.

3. The standby LED (green) should turn on. Assuming that a battery is not connected, the charging LED (red) will blink every couple of seconds.

4. Toggle the Power Switch.

5. The red Power On LED should turn on.

Software Setup

Please proceed to Get Started, where Section Installation Step by Step will quickly help you set up the development environment and then flash an application example onto your board.

###### Contents and Packaging

The main board and its accessories can be ordered separately. The accessories include:

- LCD extension board: ESP32-S3-Korvo-2-LCD

- Camera

- Connectors:

  - 20-pin FPC cable

- Fasteners:

  - Copper standoffs (x8)

  - Screws (x4)

Retail Orders

If you order a few samples, each board comes in an individual package in either antistatic bag or any packaging depending on your retailer.

For retail orders, please go to https://www.espressif.com/en/company/contact/buy-a-sample.

Wholesale Orders

If you order in bulk, the boards come in large cardboard boxes.

For wholesale orders, please go to https://www.espressif.com/en/contact-us/sales-questions.

##### Hardware Reference

###### Block Diagram

The block diagram below shows the components of ESP32-S3-Korvo-2 V3.0 and their interconnections.

ESP32-S3-Korvo-2 V3.0 Electrical Block Diagram

###### Notes on Power Distribution

Power Supply over USB and from Battery

The main power supply is 5 V and provided by a USB. The secondary power supply is 3.7 V and provided by an optional battery. The USB power itself is fed with a dedicated cable, separating from a USB cable used for an application upload. To further reduce noise from the USB, the battery may be used instead of the USB.

ESP32-S3-Korvo-2 V3.0 - Dedicated USB Power Supply Socket

ESP32-S3-Korvo-2 V3.0 - Power Supply from a Battery

As shown in the figure below, if the USB power supply and battery power supply are connected at the same time with a high VBUS, an off-state Q14, and an automatic cut-off VBAT, the USB becomes the power supply for the system.

ESP32-S3-Korvo-2 V3.0 - Power Supply Options

Independent Audio and Digital Power Supply

ESP32-S3-Korvo-2 V3.0 features independent power supplies to the audio components and ESP module. This should reduce noise in the audio signal from digital components and improve overall performance of the components.

ESP32-S3-Korvo-2 V3.0 - Digital Power Supply

ESP32-S3-Korvo-2 V3.0 - Audio Power Supply

###### GPIO Allocation Summary

The table below provides allocation of GPIOs exposed on terminals of ESP32-S3-WROOM-1 module to control specific components or functions of the board.

ESP32-S3-WROOM-1 GPIO Allocation
Pin 1 | Pin Name | ES8311 | ES7210 | Camera | LCD | Keys | MicroSD | IO Expander | Other
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
3 | EN |  |  |  |  | EN_KEY |  |  |
4 | IO4 |  |  |  |  |  | DATA0 |  |
5 | IO5 |  |  |  |  | REC, MUTE, PLAY, SET, VOL-, VOL+ |  |  |
6 | IO6 |  |  |  |  |  |  |  | BAT_MEAS_ADC
7 | IO7 |  |  |  |  |  | CMD |  |
8 | IO15 |  |  |  |  |  | CLK |  |
9 | IO16 | I2S0_MCLK | MCLK |  |  |  |  |  |
10 | IO17 | I2C_SDA | I2C_SDA | SIOD | TP_I2C_SDA |  |  | I2C_SDA |
11 | IO18 | I2C_CLK | I2C_CLK | SIOC | TP_I2C_CLK |  |  | I2C_CLK |
12 | IO8 | I2S0_DSDIN |  |  |  |  |  |  |
13 | IO19 |  |  |  |  |  |  |  | ESP_USB_DM (Reserve)
14 | IO20 |  |  |  |  |  |  |  | ESP_USB_DP (Reserve)
15 | IO3 |  |  | D5 |  |  |  |  |
16 | IO46 |  |  |  |  |  |  |  | NC
17 | IO9 | I2S0_SCLK | SCLK |  |  |  |  |  |
18 | IO10 |  | SDOUT |  |  |  |  |  |
19 | IO11 |  |  | PCLK |  |  |  |  |
20 | IO12 |  |  | D6 |  |  |  |  |
21 | IO13 |  |  | D2 |  |  |  |  |
22 | IO14 |  |  | D4 |  |  |  |  |
23 | IO21 |  |  | VSYNC |  |  |  |  |
24 | IO47 |  |  | D3 |  |  |  |  |
25 | IO48 |  |  |  |  |  |  |  | PA_CTRL
26 | IO45 | I2S0_LRCK | LRCK |  |  |  |  |  |
27 | IO0 |  |  |  | LCD_SPI_SDA | BOOT_KEY |  |  |
28 | IO35 |  |  |  |  |  |  |  | NC
29 | IO36 |  |  |  |  |  |  |  | NC
30 | IO37 |  |  |  |  |  |  |  | NC
31 | IO38 |  |  | HREF |  |  |  |  |
32 | IO39 |  |  | D9 |  |  |  |  |
33 | IO40 |  |  | XCLK |  |  |  |  |
34 | IO41 |  |  | D8 |  |  |  |  |
35 | IO42 |  |  | D7 |  |  |  |  |
36 | RXD0 |  |  |  |  |  |  |  | ESP0_UART0_RX
37 | TXD0 |  |  |  |  |  |  |  | ESP0_UART0_TX
38 | IO2 |  |  |  | LCD_SPI_DC |  |  |  |
39 | IO1 |  |  |  | LCD_SPI_CLK |  |  |  |
41 | EPAD |  |  |  |  |  |  |  |

1

  Pin - ESP32-S3-WROOM-1 module pin number, GND and power supply pins are not listed.

The GPIOs allocated to the IO expander are further expanded to multiple GPIOs.

IO Expander GPIO Allocation
IO Expander Pin | Pin Name | LCD | Other
--- | --- | --- | ---
4 | P0 |  | PA_CTRL
5 | P1 | LCD_CTRL |
6 | P2 | LCD_RST |
7 | P3 | LCD_CS |
9 | P4 | TP_INT |
10 | P5 |  | PERI_PWR_ON
11 | P6 |  | LED1
12 | P7 |  | LED2

###### Connector

Camera Connector

No. | Camera Signal | ESP32-S3 Pin
--- | --- | ---
1 | SIOD | GPIO17
2 | SIOC | GPIO18
3 | D5 | GPIO3
4 | PCLK | GPIO11
5 | D6 | GPIO12
6 | D2 | GPIO13
7 | D4 | GPIO14
8 | VSYNC | GPIO21
9 | D3 | GPIO47
10 | HREF | GPIO38
11 | D9 | GPIO39
12 | XCLK | GPIO40
13 | D8 | GPIO41
14 | D7 | GPIO42

LCD Connector

No. | LCD Signal | ESP32-S3 Pin
--- | --- | ---
1 | TP_I2C_SDA | GPIO17
2 | TP_I2C_CLK | GPIO18
3 | LCD_SPI_SDA | GPIO0
4 | LCD_SPI_DC | GPIO2
5 | LCD_SPI_CLK | GPIO1

No. | LCD Signal | IO Expander
--- | --- | ---
1 | ESP_LCD_CTRL | P1
2 | ESP_LCD_RST | P2
3 | ESP_LCD_CS | P3
4 | ESP_TP_INT | P4

###### AEC Path

AEC path provides reference signals for AEC algorithm.

ESP32-S3-Korvo-2 provides two compatible echo reference signal source designs. One is Codec (ES8311) DAC output (DAC_AOUTLN/DAC_AOUTLP), the other is PA (NS4150) output (PA_OUTL+/PA_OUTL-). The former is the default and recommended selection. Resistors R132 and R140 marked NC (no component) in the figure below should not be installed.

The echo reference signal is collected by ADC_MIC3P/ADC_MIC3N of ADC (ES7210) and then sent back to ESP32-S3 for AEC algorithm.

ESP32-S3-Korvo-2 V3.0 - AEC Codec DAC Output (click to enlarge)

ESP32-S3-Korvo-2 V3.0 - AEC PA Output (click to enlarge)

ESP32-S3-Korvo-2 V3.0 - AEC Reference Signal Collection (click to enlarge)

###### Hardware Setup Options

Using Automatic Upload

Entering of the ESP board into upload mode may be done in two ways:

- Manually by pressing both Boot and RST keys and then releasing first RST and then Boot key.

- Automatically by software performing the upload. The software is using DTR and RTS signals of the serial interface to control states of EN and IO0 of the ESP board. For details see ESP32-S3-Korvo-2 V3.0 Schematic (PDF).

###### Allocation of ESP Pins to Test Points

This section describes the allocation of test points available on the ESP32-S3-Korvo-2 V3.0 board.

The test points are bare through hole solder pads and have a standard 2.54 mm/0.1” pitch. You may need to populate them with pin headers or sockets for easy connection of external hardware.

Codec Test Point/J15

No. | Codec Pin | ESP32-S3 Pin
--- | --- | ---
1 | MCLK | GPIO16
2 | SCLK | GPIO9
3 | LRCK | GPIO45
4 | DSDIN | GPIO8
5 | ASDOUT | –
6 | GND | –

ADC Test Point/J16

No. | ADC Pin | ESP32-S3 Pin
--- | --- | ---
1 | MCLK | GPIO16
2 | SCLK | GPIO9
3 | LRCK | GPIO45
4 | SDOUT | GPIO10
5 | INT | –
6 | GND | –

UART Test Point/J17

No. | UART Pin
--- | ---
1 | 3.3V
2 | TXD
3 | RXD
4 | IO0
5 | EN
6 | GND

I2C Test Point/J18

No. | I2C Pin | ESP32-S3 Pin
--- | --- | ---
1 | 3.3V | –
2 | CLK | GPIO18
3 | SDA | GPIO17
4 | GND | –

##### Hardware Revision Details

This is the first revision of this board released.

##### Related Documents

- ESP32-S3 Series Datasheet (PDF)

- ESP32-S3-WROOM-1/1U Datasheet (PDF)

- ESP32-S3-Korvo-2 V3.0 Schematic (PDF)

- ESP32-S3-Korvo-2 V3.0 PCB Layout (PDF)

For further design documentation for the board, please contact us at sales@espressif.com.

#### ESP32-S3-Korvo-2-LCD V1.0

[中文]

This user guide will help you get started with the ESP32-S3-Korvo-2-LCD extension board and will also provide more in-depth information.

This extension board cannot be bought separately and is sold as part of the ESP32-S3-Korvo-2 V3.0 accessories.

ESP32-S3-Korvo-2-LCD extends the functionality of ESP32-S3-Korvo-2 V3.0 (referred to as main board below) by adding an LCD graphic display and capacitive touchpad.

ESP32-S3-Korvo-2-LCD V1.0

The document consists of the following major sections:

- Getting started: Overview of the board and hardware/software setup instructions to get started.

- Hardware Reference: More detailed information about the board’s hardware.

- Related Documents: Links to related documentation.

##### Getting Started

This extension board adds a 2.4” LCD graphic display with the resolution of 320x240 and a 10-point capacitive touchpad. This display is connected to ESP32-S3 over the SPI bus.

###### Description of Components

ESP32-S3-Korvo-2-LCD V1.0 - front

ESP32-S3-Korvo-2-LCD V1.0 - back

The key components of the board are described in a clockwise direction. Reserved means that the functionality is available, but the current version of the board does not use it.

Key Component | Description
--- | ---
LCD Display | A 2.4” 320x240 SPI LCD display module; the display driver/controller is Ilitek ILI934.
Home Key | (Reserved) Returns to homepage or previous page.
Signal Connector | Connects the power, ground, and signal wires between the extension board and the main board with a FPC cable.
LCD Connector | Connects LCD display to the driver circuit of this board.
TP Connector | Connects LCD display to the touch circuit of this board.

###### Start Application Development

Before powering up your board, please make sure that it is in good condition with no obvious signs of damage.

Required Hardware

- Main board: ESP32-S3-Korvo-2 V3.0

- Extension board: ESP32-S3-Korvo-2-LCD V1.0

- Two USB 2.0 cables (Standard-A to Micro-B)

- Mounting copper standoffs and screws (for stable mounting)

- A FPC cable (for connecting the main board and extension board)

- Computer running Windows, Linux, or macOS

Hardware Setup

To mount your ESP32-S3-Korvo-2-LCD onto ESP32-S3-Korvo-2:

1. Connect the two boards with the FPC cable.

2. Install copper standoffs and screws for stable mounting.

Software Setup

See Section Software Setup of the main board user guide.

##### Hardware Reference

###### Block Diagram

The block diagram below shows the components of ESP32-S3-Korvo-2-LCD and their interconnections.

ESP32-S3-Korvo-2-LCD

##### Hardware Revision Details

Initial release.

##### Related Documents

- ESP32-S3-Korvo-2 V3.0

- ESP32-S3-Korvo-2-LCD Schematic (PDF)

- ESP32-S3-Korvo-2-LCD PCB layout (PDF)

For further design documentation for the board, please contact us at sales@espressif.com.

#### ESP32-C3-Lyra V2.0

[中文]

This user guide will help you get started with ESP32-C3-Lyra V2.0 and will also provide more in-depth information.

The document consists of the following sections:

- Board Overview: Overview of the board hardware/software.

- Start Application Development: How to set up hardware/software to develop applications.

- Hardware Reference: More detailed information about the board’s hardware.

- Hardware Revision Details: Hardware revision history, known issues, and links to user guides for previous versions (if any) of the board.

- Ordering: How to buy the board.

- Related Documents: Links to related documentation.

##### Board Overview

ESP32-C3-Lyra is an ESP32-C3-based audio development board produced by Espressif for controlling light with audio. The board has control over the microphone, speaker, and LED strip, perfectly matching customers’ product development needs for ultra-low-cost and high-performance audio broadcasters and rhythm light strips.

ESP32-C3-Lyra with ESP32-C3-WROOM-02 module

###### Feature List

The main features of the board are listed below:

- Module Embedded: ESP32-C3-WROOM-02 module with a 4 MB external SPI flash

- Audio: built-in ECM microphone, speaker power amplifier, speaker connector

- LED Strip Connector: support for two types of connections, i.e., connections to addressable LED strips and RGB LED strips

- Infrared Control: support for infrared (IR) transmitting and receiving

- Keys: boot key, reset key, and six function keys (MODE, COLOR, PLAY/PAUSE, SET, VOL+/LM+, VOL-/LM-)

- USB: 1 x USB Power Port, 1 x USB-to-UART Port

- Power Supply: 5 V power supply over USB or 12 V DC power supply

###### Block Diagram

The block diagram below shows the components of ESP32-C3-Lyra and their interconnections.

ESP32-C3-Lyra Block Diagram (click to enlarge)

###### Description of Components

ESP32-C3-Lyra - front (click to enlarge)

The key components of the board are described in a clockwise direction.

Key Component | Description
--- | ---
ESP32-C3-WROOM-02 Module | It is a general-purpose Wi-Fi and Bluetooth LE module developed based on ESP32-C3, a 32-bit RISC-V single-core processor that operates at up to 160 MHz. The module has a rich set of peripherals and a high performance, making it an ideal choice for smart homes, industrial automation, health care, consumer electronics, etc. It integrates a 4 MB external SPI flash and an on-board PCB antenna. The ESP32-C3-WROOM-02U module is also compatible with this board, but it needs to connect to an external antenna.
Speaker PA Chip | NS4150 is an EMI, 3 W mono Class D audio power amplifier, amplifying audio signals from ESP32-C3 PDM_TX to drive speakers.
Speaker Output Port | Output socket to connect a speaker. The 4-ohm and 3-watt speaker is recommended. The pins have a 2.00 mm/0.08” pitch.
Function Press Keys | Six function press keys, including MODE, COLOR, PLAY/PAUSE, SET, VOL+/LM+, VOL-/LM-. They are routed to the ESP32-C3-WROOM-02 Module and intended for the development and testing of a UI for audio applications or LED strips using dedicated APIs.
Boot/Reset Press Keys | Boot: holding down the Boot key and momentarily pressing the Reset button initiates the firmware upload mode. Then you can upload firmware through the serial port. Reset: pressing this key alone resets the system.
USB-to-UART Port | Functions as the communication interface between the PC and the ESP32-C3-WROOM-02 module.
USB-to-UART Bridge Chip | The single-chip USB-UART bridge CP2102N provides up to 3 Mbps transfer rates for software download and debugging.
USB Power Port | Provides power to the board. It is recommended to use at least 5 V/2 A power adapters to ensure a stable power supply.
System Power Switch | System Power on/off knob. Toggling it to ON turns the 5 V system power on; toggling it to OFF turns the 5 V system power off.
LED Strip Power Selection Switch | Toggle this switch to select between a 5 V power supply over USB and a 12 V DC power supply for your LED strip according to the working voltage of the LED strip and the type of the power adapter you actually use.
12 V DC Power Port | Supports 12 V DC power adapters with a maximum current of 2 A. The DC power Jack contact have an outer diameter of 5.5 mm and an inner contact diameter of 2.5 mm.
12 V to 5 V Buck Chip | The 12 V to 5 V buck chip MP2313 is a high-efficiency synchronous step-down converter that operates at 1 A and 2 MHz.
Addressable LED Strip Port | It is a male pin header connector with 4 x 1 pins and a 2.54 mm pitch. It can connect to the addressable LED strip that is controlled with a single wire. It supports 5 V and 12 V LED strips, such as WS2811 and WS2812 LED. ESP32-C3 can send commands to control the LED strips over RMT or SPI.
RGB LED Strip Port | It is a male pin header connector with 4 x 1 pins and a 2.54 mm pitch. It can connect to regular RGB LED strips (non-addressable, individual wire per color) that operate at 5 V or 12 V. ESP32-C3 can output PWM waveform via this port to control the LED strips.
System Power LED | It turns red when System Power Switch is toggled to ON.
IR Receiver | IRM-H638T/TR2 is a miniature SMD type infrared remote control system receiver. The demodulated output signal can directly be decoded by ESP32-C3.
IR Transmitter | IR67-21C/TR8 is an infrared emitting diode. It is spectrally matched with silicon photodiode and phototransistor.
Microphone | On-board ECM microphone. Signals picked up by it are amplified via transistors and sent to the analog-to-digital converter (ADC) of ESP32-C3-WROOM-02.
System LED | It is an RGB LED, model WS2812C, controlled by the ESP32-C3-WROOM-02 via GPIO, which can be used to indicate the operating status of the audio application.

###### Default Firmware and Function Test

Each ESP32-C3-Lyra comes with a pre-built default firmware that allows you to test its functions including LED control (LEDC), remote control transceiver (RMT), ADC, and pulse-density modulation (PDM_TX). This section describes how to test peripheral’s function with the pre-built firmware.

> Note

> The default firmware of ESP32-C3-Lyra sold in the Developing IoT Projects with ESP32-C3 Package II provides a musical rhythm light ring effect.

Preparing Hardware

See Section Required Hardware and Optional Hardware for more information.

- 1 x ESP32-C3-Lyra

- 2 x USB 2.0 cable (Standard-A to Micro-B)

- 1 x Computer running Windows, Linux, or macOS

- 1 x 5 V RGB LED strip WS2812 (optional)

- 1 x Mobile phone or music player

- 1 x Speaker (optional)

Connecting Hardware

- Before powering up your board, please make sure that it is in good condition with no obvious signs of damage.

- Connect the board to the 5 V power supply through the USB Power Port using a USB cable. After the board is powered up, you will notice that the System Power LED turns on, which means the board is powered up. If the LED is not on, please toggle the System Power Switch.

- Toggle the LED Strip Power Selection Switch to the USB power side.

- Connect the board to the computer through the USB-to-UART Port using a USB cable.

Testing Default Firmware

> Note

> If you are developing with ESP32-C3-Lyra provided in the Developing IoT Projects with ESP32-C3 Package II, please skip this step.

1. Press the Reset Press Key on the board.

2. The board automatically starts the flash test. The log shown on a PC connected to USB-to-UART Port is as follows:

       Step1 Flash Test Start
       Step1 Flash Test OK

3. The board tests the Function Press Keys. Please press the key as the log prompts. For example, press VOL+ when you see the following log:

       Step2 Keys Test Start
       Please press The Key: VOL+

4. The board tests the System LED. You will see the LED keep switching between red, blue, and green. Then, press the key `VOL+/LM+` to proceed to the next step.

5. The board tests LEDC (PWM). If you connect an RGB LED strip to the RGB LED Strip Port, you will see the LEDs breathing. Then, press the key `VOL+/LM+` to proceed to the next step.

6. The board tests ADC. If you play the 1 kHz sine audio signal close to the Microphone with the mobile phone or music player, the following log will be seen when the board detects the audio signal:

       Step5 Adc Test Start
       Please play 1khz audio
       Step5 Adc Test OK

7. The board tests the PDM_TX function. Connect the speaker to the Speaker Output Port and you will hear the music played from flash.

###### Software Support

ESP-ADF is the development framework for ESP32-C3-Lyra. To see which version of ESP-ADF is supported for this board, please go to the section Hardware.

Below are other software repositories developed by Espressif that may help you experiment with the functions of ESP32-C3-Lyra.

- ESP-IDF: development framework for Espressif SoCs based on FreeRTOS with a rich set of components, including LED control (LEDC), ADC, RMT, SPI etc.

Application examples for this board can be found at application example .

##### Start Application Development

This section provides instructions on how to do hardware and software setup and flash firmware onto the board to develop your own application.

###### Required Hardware

Hardware | Qty | Note
--- | --- | ---
ESP32-C3-Lyra | 1 | –
USB 2.0 cables (Standard-A to Micro-B) | 2 | One for USB power supply, the other for flashing firmware onto the board. Be sure to use an appropriate USB cable. Some cables are for charging only and do not provide the needed data lines nor work for programming the boards.
Computer running Windows, Linux, or macOS | 1 | –
Speaker | 1 | The 4-ohm 3-watt speaker is recommended. It should be fitted with JST PH 2.0 2-Pin plugs. In case you do not have this type of plug it is also fine to use Dupont female jumper wires during development.

###### Optional Hardware

Hardware | Qty | Note
--- | --- | ---
12 V DC adapter | 1 | The maximum operating current of the adapter is 2 A. It provides power supply for 12 V LED strips.
5 V or 12 V addressable LED strip/ring | 1 | It is recommended to use WS2812/WS2811 LED strip (a female connector with 4 x 1 pins and a 2.54 mm pitch), or a WS2812 LED ring with 16 individually addressable RGB LEDs assembled (a female connector with 3 x 1 pins and a 2.54 mm pitch). This LED strip/ring should be connected to the Addressable LED Strip Port (JP2).
5 V or 12 V RGB LED strip | 1 | It should have a female connector with 4 x 1 pins and a 2.54 mm pitch. This LED strip should be connected to RGB LED Strip Port (JP1).

###### Power Supply Options

There are two ways to provide power to the board:

- USB Power Port (5 V)

- 12 V DC Power Port

###### Hardware Setup

Prepare the board for loading of the first sample application:

1. Connect the speaker to the Speaker Output Port.

2. (Optional) Connect the LED strip to the development board through the Addressable LED Strip Port or the RGB LED Port depending on the type of your LED strip.

3. Connect the power supply to the development board through the USB Power Port (5 V) or the 12 V DC Power Port accordingly to supply power for your LED strip.

4. (Optional) Toggle the LED Strip Power Selection Switch depending on the working voltage and current of your LED strip.

   Note

   If you toggle the switch to the wrong side, the light strip will work abnormally. Do not power the 5 V LED strip with the 12 V DC adapter. Otherwise, the light strip will be damaged.

5. Toggle the System Power Switch to ON. The red System Power LED should turn on.

6. Connect the board to the computer through the USB-to-UART Port using a USB cable.

Now the board is ready for software setup.

###### Software Setup

After hardware setup, you can proceed to Get Started to prepare development tools.

For more software information on developing applications, please go to Software Support.

##### Hardware Reference

This section provides more detailed information about the board’s hardware.

###### GPIO Allocation

The table provides the allocation of GPIOs exposed on terminals of the ESP32-C3-WROOM-02 module to control specific components or functions of the board.

###### Power Distribution

Power Supply over USB or from 12 V/2 A DC Input

There are two ways to power the development board: 5 V USB Power Port or 12 V/2 A DC input.

ESP32-C3-Lyra - Dedicated USB Power Supply Socket

ESP32-C3-Lyra - Power Supply from 12 V DC Input

LED Strip Power Selection Switch

According to the working voltage and current of your LED strip, select a proper power adapter and the port, and toggle the LED Strip Power Selection Switch to the corresponding side to power up the LED strip.

LED Strip Power Selection Switch

12 V to 5 V Buck Power

12 V to 5 V Buck Power Circuit

System 3.3 V Power

System 3.3 V Power Circuit

###### Connector

RGB LED Strip Connector (JP1)

No. | Signal Name | ESP32-C3 Pin
--- | --- | ---
1 | VCC_12V_5V | –
2 | LED_G | GPIO6
3 | LED_R | GPIO5
4 | LED_B | GPIO4

Addressable LED Strip Connector (JP2)

No. | Signal Name | ESP32-C3 Pin
--- | --- | ---
1 | VCC_12V_5V | –
2 | DIN | GPIO7
3 | DIN | GPIO7
4 | GND | –

###### Pinout of Extension Headers

There are several pin headers available to connect external components, check the state of particular signal bus, or debug operation of ESP32-C3. Note that some signals are shared. See Section GPIO Allocation for details.

UART Header (JP12)

No. | Signal Name | ESP32-C3 Pin
--- | --- | ---
1 | VCC_3V3 | –
2 | ESP_EN | EN
3 | ESP_BOOT | GPIO9
4 | ESP_UART_RXD | U0RXD
5 | ESP_UART_TXD | U0TXD
6 | GND | –

I2C Header (JP8)

No. | Signal Name | ESP32-C3 Pin
--- | --- | ---
1 | VCC_3V3 | –
2 | I2C_CLK | GPIO8
3 | I2C_DATA | GPIO9
4 | GND | –

##### Hardware Revision Details

No previous revisions.

##### Ordering

If you order a few samples, each board comes in an individual package.

For retail orders, please go to the official website https://www.espressif.com/en/company/contact/buy-a-sample, or directly order in our Taobao shop https://world.taobao.com/item/677273363812.htm?spm=a21wu.12321156-tw.recommend-tpp.4.19a61924ZMaqpf.

For wholesale orders, please go to the official website https://www.espressif.com/en/contact-us/sales-questions.

##### Related Documents

- Datasheet

  - ESP32-C3 Series Datasheet (PDF)

  - ESP32-C3-WROOM-02 & ESP32-C3-WROOM-02U Datasheet (PDF)

- Schematic

  - ESP32-C3-Lyra Schematic (PDF)

- PCB Layout

  - ESP32-C3-Lyra PCB Layout (PDF)

For further design documentation for the board, please contact us at sales@espressif.com.

### Audio Samples

Music files in this section are intended for testing of audio applications. The files are organized into different Formats and Sample Rates.

#### Formats

The tables below provides an audio file converted from ‘wav’ format into several other audio formats.

##### Long Samples

The audio track duration in this section is 3 minutes and 7 seconds.

###### Two Channel Audio

No | Format | Audio File | Size [kB]
--- | --- | --- | ---
1 | aac | ff-16b-2c-44100hz.aac | 2,995
2 | ac3 | ff-16b-2c-44100hz.ac3 | 2,994
3 | aiff | ff-16b-2c-44100hz.aiff | 33,002
4 | flac | ff-16b-2c-44100hz.flac | 22,406
5 | m4a | ff-16b-2c-44100hz.m4a | 3,028
6 | mp3 | ff-16b-2c-44100hz.mp3 | 2,994
7 | mp4 | ff-16b-2c-44100hz.mp4 | 3,079
8 | ogg | ff-16b-2c-44100hz.ogg | 2,612
9 | opus | ff-16b-2c-44100hz.opus | 2,598
10 | ts | ff-16b-2c-44100hz.ts | 5,510
11 | wav | ff-16b-2c-44100hz.wav | 32,229
12 | wma | ff-16b-2c-44100hz.wma | 3,227

Playlist containing all above files: ff-16b-2c-playlist.m3u

###### Single Channel Audio

No | Format | Audio File | Size [kB]
--- | --- | --- | ---
1 | aac | ff-16b-1c-44100hz.aac | 1,650
2 | ac3 | ff-16b-1c-44100hz.ac3 | 2,193
3 | aiff | ff-16b-1c-44100hz.aiff | 16,115
4 | amr | ff-16b-1c-8000hz.amr | 299
5 | flac | ff-16b-1c-44100hz.flac | 10,655
6 | m4a | ff-16b-1c-44100hz.m4a | 1,628
7 | mp3 | ff-16b-1c-44100hz.mp3 | 1,463
8 | ogg | ff-16b-1c-44100hz.ogg | 1,558
9 | opus | ff-16b-1c-44100hz.opus | 1,641
10 | wav | ff-16b-1c-44100hz.wav | 16,115
11 | wma | ff-16b-1c-44100hz.wma | 3,151

Playlist containing all above files: ff-16b-1c-playlist.m3u

##### Short Samples

If you need shorter audio files for testing, this section provides 16 seconds audio tracks.

###### Two Channel Audio

No | Format | Audio File | Size [kB]
--- | --- | --- | ---
1 | aac | gs-16b-2c-44100hz.aac | 241
2 | ac3 | gs-16b-2c-44100hz.ac3 | 380
3 | aiff | gs-16b-2c-44100hz.aiff | 2,792
4 | flac | gs-16b-2c-44100hz.flac | 1,336
5 | m4a | gs-16b-2c-44100hz.m4a | 258
6 | mp3 | gs-16b-2c-44100hz.mp3 | 254
7 | mp4 | gs-16b-2c-44100hz.mp4 | 259
8 | ogg | gs-16b-2c-44100hz.ogg | 229
9 | opus | gs-16b-2c-44100hz.opus | 219
10 | ts | gs-16b-2c-44100hz.ts | 286
11 | wav | gs-16b-2c-44100hz.wav | 2,792
12 | wma | gs-16b-2c-44100hz.wma | 276

Playlist containing all above files: gs-16b-2c-playlist.m3u

###### Single Channel Audio

No | Format | Audio File | Size [kB]
--- | --- | --- | ---
1 | amr | gs-16b-1c-8000hz.amr | 25
2 | aac | gs-16b-1c-44100hz.aac | 137
3 | ac3 | gs-16b-1c-44100hz.ac3 | 190
4 | aiff | gs-16b-1c-44100hz.aiff | 1,397
5 | flac | gs-16b-1c-44100hz.flac | 645
6 | m4a | gs-16b-1c-44100hz.m4a | 258
7 | mp3 | gs-16b-1c-44100hz.mp3 | 127
8 | ogg | gs-16b-1c-44100hz.ogg | 144
9 | opus | gs-16b-1c-44100hz.opus | 132
10 | wav | gs-16b-1c-44100hz.wav | 1,497
11 | wma | gs-16b-1c-44100hz.wma | 276

Playlist containing all above files: gs-16b-1c-playlist.m3u

#### Sample Rates

The files in this section have been prepared by converting a single audio file into different sampling rates defined in MPEG Layer III specification. Both mono and stereo versions of files are provided. The bit depth of files is 16 bits.

| Sample Rate | MPEG III | Channels | Bit Rate | Size
--- | --- | --- | --- | --- | ---
Audio File | [Hz] | ver |  | [kbit/s] | [kB]
ff-16b-1c-8000hz.mp3 | 8000 | 2.5 | mono | 8 | 183
ff-16b-1c-11025hz.mp3 | 11025 | 2.5 | mono | 16 | 366
ff-16b-1c-12000hz.mp3 | 12000 | 2.5 | mono | 16 | 366
ff-16b-1c-16000hz.mp3 | 16000 | 2 | mono | 24 | 548
ff-16b-1c-22050hz.mp3 | 22050 | 2 | mono | 32 | 731
ff-16b-1c-24000hz.mp3 | 24000 | 2 | mono | 32 | 731
ff-16b-1c-32000hz.mp3 | 32000 | 1 | mono | 48 | 1,097
ff-16b-1c-44100hz.mp3 | 44100 | 1 | mono | 64 | 1,462
ff-16b-2c-8000hz.mp3 | 8000 | 2.5 | joint stereo | 24 | 549
ff-16b-2c-11025hz.mp3 | 11025 | 2.5 | joint stereo | 32 | 731
ff-16b-2c-12000hz.mp3 | 12000 | 2.5 | joint stereo | 32 | 731
ff-16b-2c-16000hz.mp3 | 16000 | 2 | joint stereo | 48 | 1,097
ff-16b-2c-22050hz.mp3 | 22050 | 2 | joint stereo | 64 | 1,462
ff-16b-2c-24000hz.mp3 | 24000 | 2 | joint stereo | 64 | 1,462
ff-16b-2c-32000hz.mp3 | 32000 | 1 | joint stereo | 96 | 2,194
ff-16b-2c-44100hz.mp3 | 44100 | 1 | joint stereo | 128 | 2,924

Playlist containing all above files: ff-16b-mp3-playlist.m3u

Original music files: “Furious Freak” and “Galway”, Kevin MacLeod (incompetech.com), Licensed under Creative Commons: By Attribution 3.0, http://creativecommons.org/licenses/by/3.0/

## Resources

- Third party frameworks and libraries to develop audio applications with Espressif chips:

  > - The JOSH operating system supports the ESP32 and can be used in scenarios such as intelligent voice interaction, smart home appliances, and smart gateways.

- Third party audio development modules and boards that work with ESP-ADF:

  > - ESP32-A1S Audio Module equipped CodeC audio decoding chip that supports music playback and recording, and 4MB PSRAM. The module application schematic is available in datasheet.

- The esp32.com forum is a place to ask questions and find community resources. The forum has a section dedicated to ESP-ADF.

- This ESP Audio Development Framework inherits from ESP IoT Development Framework and you can learn about it in ESP-IDF Programming Guide.

- Check the Issues section on GitHub if you find a bug or have a feature request. Please check existing Issues before opening a new one.

- If you’re interested in contributing to ESP Audio Development Framework, please check the Contributions Guide.

- Several books have been written about ESP32 and they are listed on Espressif web site.

- For additional ESP32 product related information, please refer to documentation Section of Espressif site.

- To buy audio development boards, check list of distributors under Get Samples on Espressif web site.

## Copyrights and Licenses

### Software Copyrights

All original source code in this repository is Copyright (C) 2015-2018 Espressif Systems. This source code is licensed under the ESPRESSIF MIT License as described in the file LICENSE.

Additional third party copyrighted code is included under the following licenses:

- mp3 library is Copyright (c) 2005-2008, The Android Open Source Project, and is licensed under the Apache License Version 2.0.

- aac library is Copyright (c) 2005-2008, The Android Open Source Project, and is licensed under the Apache License Version 2.0.

- amr library is Copyright (C) 2009 Martin Storsjo and is licensed under the Apache License Version 2.0.

- opus library, Copyright 2001-2011 Xiph.Org, Skype Limited, Octasic,Jean-Marc Valin, Timothy B. Terriberry, CSIRO, Gregory Maxwell, Mark Borgerding, Erik de Castro Lopo, is licensed under 3-clause BSD license.

- flac library, Copyright (C) 2011-2016 Xiph.Org Foundation, is licensed under Xiph.Org’s BSD-like license.

- vorbis library, Copyright (c) 2002-2020 Xiph.org Foundation, is licensed under the 3-Clause BSD license.

- aac-enc library is Copyright 2003-2010, VisualOn, and is licensed under the Apache License Version 2.0.

- adpcm library is Copyright (C) 2020 aikiriao <samuraiaiki@gmail.com>.

- jpeg-dec library is Copyright (C) 2019, ChaN.

- alac library is Copyright (C) 2004, developed by Apple, and is licensed under the Apache License Version 2.0.

Please refer to the COPYRIGHT in ESP-IDF Programming Guide

Where source code headers specify Copyright & License information, this information takes precedence over the summaries made here.

## English-Chinese Glossary

This document lists terms that are used in Espressif Audio Development Framework Guide and other audio related documentation. Each term is followed by its Chinese equivalents and some have definitions.

AAC

  Chinese equivalent: AAC

  Abbreviation for Advanced Audio Coding, an industry-standard audio compression format.

acoustic

  Chinese equivalent: 声学

acoustic calibrator

  Chinese equivalent: 声校准器

  Also known as sound level calibrator.

acoustic echo cancellation

  Chinese equivalent: 声学回声消除

  Spelled-out form of AEC.

AEC

  Chinese equivalent: AEC

  Abbreviation for acoustic echo cancellation.

Advanced Audio Distribution Profile

  Chinese equivalent: 高级音频分发框架

  Spelled-out form of A2DP.

A2DP

  Chinese equivalent: A2DP.

  Abbreviation for Advanced Audio Distribution Profile.

A2DP sink

  Chinese equivalent: A2DP sink

A2DP source

  Chinese equivalent: A2DP source

AFE

  Chinese equivalent: AFE

  Abbreviation for audio front end. Espressif audio front-end algorithm framework is developed by Espressif AI Lab to provide high-quality and stable audio data to the host.

AirKiss

  Chinese equivalent: AirKiss

  AirKiss is a quick-connection technique provided by Weixin device platform for Wi-Fi devices to configure network connection.

AMR

  Chinese equivalent: AMR

  Abbreviation for Adaptive Multi-Rate, an audio compression format optimized for speech coding.

AMR-NB

  Chinese equivalent: AMR-NB

  Abbreviation for Adaptive Multi-Rate Narrowband, a narrowband speech audio coding standard developed based on Adaptive Multi-Rate encoding.

AMR-WB

  Chinese equivalent: AMR-WB

  Abbreviation for Adaptive Multi-Rate Wideband, a wideband speech audio coding standard developed based on Adaptive Multi-Rate encoding.

analog-to-digital converter

  Chinese equivalent: 模拟数字转换器

  Spelled-out form of ADC.

ADC

  Chinese equivalent: ADC

  Abbreviation for analog-to-digital converter.

audio codec

  Chinese equivalent: 音频编码解码器

audio forge

  Chinese equivalent: 音频塑造

  A combination of several audio backend processing techniques, including resample, downmix, automatic level control, equalizer and sonic. Users can enable or disable certain techniques as needed.

audio gate

  Chinese equivalent: 音频网关

  Spelled-out form of AG.

AG

  Chinese equivalent: AG

  Abbreviation for audio gate.

audio front end

  Chinese equivalent: 声学前端

  Spelled-out form of AFE.

audio passthru

  Chinese equivalent: 音频透传

  Also known as pipeline passthru. It is an audio technique that allows audio files to pass through a pipeline unaltered.

audio pipeline

  Chinese equivalent: 音频管道

  Often used as “pipeline”. It is a chain of audio processing elements arranged in a particular order so that the output of each element is the input of the next.

Audio Video Remote Control Profile

  Chinese equivalent: 音视频远程控制规范

  Spelled-out form of AVRCP.

AVRCP

  Chinese equivalent: AVRCP

  Abbreviation for Audio Video Remote Control Profile.

automatic gain control

  Chinese equivalent: 自动增益控制

  Spelled-out form of AGC.

AGC

  Chinese equivalent: AGC

  Abbreviation for automatic gain control.

automatic level control

  Chinese equivalent: 自动电平控制

  Spelled-out form of ALC.

ALC

  Chinese equivalent: ALC

  Abbreviation for automatic level control.

automatic speech recognition

  Chinese equivalent: 自动语音识别

  Spelled-out form of ASR.

aux cable

  Chinese equivalent: aux 音频线

  Also known as auxiliary cable.

ASR

  Chinese equivalent: ASR

  Abbreviation for automatic speech recognition.

bandwidth

  Chinese equivalent: 带宽

Bass Frequency

  Chinese equivalent: 低频

BCLK

  Chinese equivalent: BCLK

  Abbreviation for base clock.

BluFi

  Chinese equivalent: BluFi

  A Wi-Fi network configuration function via Bluetooth channel. See ESP-IDF Programming Guide for more information.

cavity

  Chinese equivalent: 腔体

command word

  Chinese equivalent: 命令词

core dump

  Chinese equivalent: 核心转储

cutoff frequency

  Chinese equivalent: 截止频率

decoder

  Chinese equivalent: 解码器

digital media renderer

  Chinese equivalent: 数字媒体渲染器

  Spelled-out form of DMR.

digital signal processor

  Chinese equivalent: 数字信号处理器

  Spelled-out form of DSP.

DSP

  Chinese equivalent: DSP

  Abbreviation for digital signal processor or digital signal processing.

digital-to-analog converter

  Chinese equivalent: 数字模拟转换器

  Spelled-out form of DAC.

dispatcher

  Chinese equivalent: 调度器

distortion

  Chinese equivalent: 失真

DAC

  Chinese equivalent: DAC

  Abbreviation for digital-to-analog converter.

Digital Living Network Alliance

  Chinese equivalent: 数字生活网络联盟

  Spelled-out form of DLNA.

DLNA

  Chinese equivalent: DLNA

  Abbreviation for Digital Living Network Alliance.

DMR

  Chinese equivalent: DMR

  Abbreviation for digital media renderer.

downmix

  Chinese equivalent: 向下混叠

  An audio processing technique that mixes more audio streams to less output audio streams.

DuerOS

  Chinese equivalent: DuerOS

  DuerOS is a conversational AI system developed by Baidu.

echo

  Chinese equivalent: 回声

  > A reflection of sound that arrives at the listener with a delay after the direct sound.

echo reference signal

  Chinese equivalent: 回声参考信号

electret condenser microphone

  Chinese equivalent: 驻极体麦克风

  Spelled-out form of ECM.

ECM

  Chinese equivalent: ECM

  Abbreviation for electret condenser microphone.

element

  Chinese equivalent: 元素

  Also known as audio element. It is the basic building block for the application programmer developing with ADF. Every decoder, encoder, filter, input stream, or output stream is in fact an audio element.

encoder

  Chinese equivalent: 编码器

equalizer

  Chinese equivalent: 均衡器

ESP VoIP

  Chinese equivalent: ESP VoIP

  ESP VoIP is a telephone client based on the standard SIP protocol, which can be used in some P2P or audio conference scenarios.

fast Fourier transform

  Chinese equivalent: 快速傅里叶变换

  Spelled-out form of FFT.

FFT

  Chinese equivalent: FFT

  Abbreviation for fast Fourier transform.

FatFs

  Chinese equivalent: FatFs

FatFs stream

  Chinese equivalent: FatFs 流

FLAC

  Chinese equivalent: FLAC

  Abbreviation for Free Lossless Audio Codec, an audio coding format for lossless compression of digital audio.

flexible pipeline

  Chinese equivalent: 灵活管道

FPS

  Chinese equivalent: FPS

  Abbreviation for frames per second.

frames per second

  Chinese equivalent: 每秒传输帧数

  Spelled-out form of FPS.

frequency response

  Chinese equivalent: 频率响应

full band

  Chinese equivalent: 全频带

  Spelled-out form of FB.

FB

  Chinese equivalent: FB

  Abbreviation for full band.

Hands-Free

  Chinese equivalent: 免提

  Spelled-out form of HF.

HF

  Chinese equivalent: HF

  Abbreviation for Hands-Free.

Hands-Free Audio Gateway

  Chinese equivalent: 免提音频网关

  Spelled-out form of HFP-AG.

Hands-Free Profile

  Chinese equivalent: 免提规范

Hands-Free Unit

  Chinese equivalent: 免提组件

HFP

  Chinese equivalent: HFP

  Abbreviation for Hands-Free Profile.

hardware abstraction layer

  Chinese equivalent: 硬件抽象层

  Spelled-out form of HAL.

HAL

  Chinese equivalent: HAL

  Abbreviation for hardware abstraction layer.

headset

  Chinese equivalent: 耳机

HFP-AG

  Chinese equivalent: HFP-AG

  Abbreviation for Hands-Free Audio Gateway.

Hi-Fi speaker

  Chinese equivalent: 高保真音箱

  Also known as high-fidelity speaker.

High Frequency

  Chinese equivalent: 高频

high-fidelity microphone

  Chinese equivalent: 高保真麦克风

HLS

  Chinese equivalent: HLS

  Abbreviation for HTTP Live Streaming.

HTTP stream

  Chinese equivalent: HTTP 流

HTTP Live Streaming

  Chinese equivalent: HTTP 直播流

  Spelled-out form of HLS.

I2S stream

  Chinese equivalent: I2S 流

insertion loss

  Chinese equivalent: 插入损失

Internet radio

  Chinese equivalent: 网络电台

Internet of Things

  Chinese equivalent: 物联网

IoT

  Chinese equivalent: IoT

  Abbreviation for Internet of Things.

JPEG

  Chinese equivalent: JPEG

  A commonly used method of lossy compression for digital images. Same as JPG.

JPG

  Chinese equivalent: JPG

  A commonly used method of lossy compression for digital images. Same as JPEG.

Light and Versatile Graphics Library

  Chinese equivalent: 轻量级多功能图形库

  Spelled-out form of LVGL

low-pass filter

  Chinese equivalent: 低通滤波器

LVGL

  Chinese equivalent: LVGL

  Abbreviation for Light and Versatile Graphics Library.

M3U8

  Chinese equivalent: M3U8

  The Unicode version of M3U is M3U8, which uses UTF-8-encoded characters.

M4A

  Chinese equivalent: M4A

  An audio encoding format for lossless compression of digital audio.

mass production

  Chinese equivalent: 量产

maximum output power

  Chinese equivalent: 最大输出功率

MCLK

  Chinese equivalent: MCLK

  Abbreviation for master clock.

mel-frequency cepstral coefficients

  Chinese equivalent: 梅尔频率倒谱系数

  Spelled-out form of MFCC.

MFCC

  Chinese equivalent: MFCC

  Abbreviation for mel-frequency cepstral coefficients.

microphone

  Chinese equivalent: 麦克风

mic

  Chinese equivalent: 麦克风

  Informal form for microphone.

micro-electro-mechanical systems microphone

  Chinese equivalent: 微型机型系统麦克风

  Spelled-out form of MEMS mic.

MEMS mic

  Chinese equivalent: MEMS 麦克风

  Abbreviation for micro-electro-mechanical systems microphone.

microphone gain

  Chinese equivalent: 麦克风增益

microphone hole

  Chinese equivalent: 麦克孔

microSD card

  Chinese equivalent: microSD 卡

MP3

  Chinese equivalent: MP3

MP4

  Chinese equivalent: MP4

MultiNet

  Chinese equivalent: MultiNet

  MultiNet is a lightweight model specially designed based on CRNN and CTC for the implementation of multi-command recognition.

multi-room

  Chinese equivalent: 多房间

Multi-Room Music

  Chinese equivalent: Multi-Room Music

  ESP Multi-Room Music is a Wi-Fi-based communication protocol to share music across multiple interconnected speakers. Under this protocol, those connected speakers form a Group. They can play music synchronously and are controlled together, which can easily achieve a theater-grade stereo surround sound system.

narrowband

  Chinese equivalent: 窄带

  Spelled-out form of NB.

NB

  Chinese equivalent: NB

  Abbreviation for narrowband.

NimBLE

  Chinese equivalent: NimBLE

  > An open-source Bluetooth Low Energy or Bluetooth Smart stack.

noise criteria curve

  Chinese equivalent: 噪声标准曲线

  Also known as NC curve.

noise rating curve

  Chinese equivalent: 噪声评价曲线

  Also known as NR curve.

noise floor

  Chinese equivalent: 本底噪声

noise suppression

  Chinese equivalent: 噪声抑制

  Spelled-out form of NS.

NS

  Chinese equivalent: NS

  Abbreviation for noise suppression.

non-volatile storage

  Chinese equivalent: 非易失性存储

  Spelled-out form of NVS.

NVS

  Chinese equivalent: NVS

  Abbreviation for non-volatile storage.

OGG

  Chinese equivalent: OGG

  An audio compression format.

OPUS

  Chinese equivalent: OPUS

  A lossy audio coding format.

PCM

  Chinese equivalent: PCM

  Abbreviation for pulse-code modulation.

pixel

  Chinese equivalent: 像素

playback

  Chinese equivalent: 回放

  It is a noun. The verb is “play back”.

programmable gain amplifier

  Chinese equivalent: 可编程增益放大器

  Spelled-out form of PGA.

PGA

  Chinese equivalent: PGA

  Abbreviation for programmable gain amplifier.

protractor

  Chinese equivalent: 量角尺

pulse-code modulation

  Chinese equivalent: 脉冲编码调制

  Spelled-out form of PCM.

raw stream

  Chinese equivalent: 原始流

resample

  Chinese equivalent: 重采样

resample filter

  Chinese equivalent: 重采样过滤器

resonant frequency

  Chinese equivalent: 谐振频率

reverberation

  Chinese equivalent: 混响

RGB

  Chinese equivalent: RGB

  The RGB color model is an additive color model in which the red, green, and blue primary colors of light are added together in various ways to reproduce a broad array of colors.

ring buffer

  Chinese equivalent: 环形缓冲区

SBC

  Chinese equivalent: SBC

  Abbreviation for subband codec.

SD card

  Chinese equivalent: SD 卡

Session Initiation Protocol

  Chinese equivalent: 会话发起协议

  Spelled-out form of SIP.

signal-to-echo ratio

  Chinese equivalent: 信回比

signal-to-noise ratio

  Chinese equivalent: 信噪比

  Spelled-out form of SNR.

SIP

  Chinese equivalent: SIP

  Abbreviation for Session Initiation Protocol.

SNR

  Chinese equivalent: SNR

  Abbreviation for signal-to-noise ratio.

SmartConfig

  Chinese equivalent: SmartConfig

  The SmartConfig TM is a provisioning technology developed by TI to connect a new Wi-Fi device to a Wi-Fi network. It uses a mobile app to broadcast the network credentials from a smartphone, or a tablet, to an un-provisioned Wi-Fi device.

sonic

  Chinese equivalent: 变声

  An audio processing technique that modifies sound frequency and speed.

sound card

  Chinese equivalent: 声卡

  Also known as audio card.

sound level meter

  Chinese equivalent: 分贝仪

  Also known as sound pressure level meter.

sound pickup hole

  Chinese equivalent: 拾音孔

sound pickup tube

  Chinese equivalent: 拾音管道

sound transmission loss

  Chinese equivalent: 传声损失

  Spelled-out form of STL.

speech

  Chinese equivalent: 语音

speech recognition

  Chinese equivalent: 语音识别

  Spelled-out form of SR.

SR

  Chinese equivalent: SR

  Abbreviation for speech recognition.

SPI Flash File System

  Chinese equivalent: SPI 闪存文件系统

  Spelled-out form of SPIFFS.

SPIFFS

  Chinese equivalent: SPIFFS

  Abbreviation for SPI Flash File System.

SPIFFS stream

  Chinese equivalent: SPIFFS 流

subband codec

  Chinese equivalent: 次频带编码

  Spelled-out form of SBC.

STL

  Chinese equivalent: STL

  Abbreviation for sound transmission loss.

super wide band

  Chinese equivalent: 超宽频带

  Spelled-out form of SWB.

SWB

  Chinese equivalent: SWB

  Abbreviation for super wide band.

tape measure

  Chinese equivalent: 卷尺

text-to-speech

  Chinese equivalent: 语音合成

  Spelled-out form of TTS.

TTS

  Chinese equivalent: TTS

  Abbreviation for text-to-speech.

tolerance

  Chinese equivalent: 公差

tone

  Chinese equivalent: 提示音

total harmonic distortion

  Chinese equivalent: 总谐波失真

  Spelled-out form of THD.

THD

  Chinese equivalent: THD

  Abbreviation for total harmonic distortion.

voice activity detection

  Chinese equivalent: 语音活动检测

  Spelled-out form of VAD.

VAD

  Chinese equivalent: VAD

  Abbreviation for voice activity detection.

VoIP

  Chinese equivalent: VoIP

  Abbreviation for Voice over Internet Protocol.

wake word

  Chinese equivalent: 唤醒词

wake word engine

  Chinese equivalent: 唤醒词引擎

  Spelled-out form of WWE.

WakeNet

  Chinese equivalent: WakeNet

  WakeNet is a wake word engine built upon neural network for low-power embedded MCUs.

wake-up

  Chinese equivalent: 唤醒

  It is a noun.

wideband

  Chinese equivalent: 宽带

  Spelled-out form of WB.

WB

  Chinese equivalent: WB

  Abbreviation for wideband.

WWE

  Chinese equivalent: WWE

  Abbreviation for wake word engine.

YUV

  Chinese equivalent: YUV

  A color model typically used as part of a color image pipeline.

## About

This is documentation of ESP-ADF, the framework to develop audio applications for ESP32 chip by Espressif.

The ESP32 is 2.4 GHz Wi-Fi and Bluetooth combo, 32 bit dual core chip running up to 240 MHz, designed for mobile, wearable electronics, and Internet-of-Things (IoT) applications. It has several peripherals on board including I2S interfaces to easy integrate with dedicated audio chips. These hardware features together with the ESP-ADF software provide a powerful platform to implement audio applications including native wireless networking and powerful user interface.

The ESP-ADF provides a range of API components including Audio Streams, Codecs and Services organized in Audio Pipeline, all integrated with audio hardware through Media HAL and with Peripherals onboard of ESP32.

Espressif Audio Development Framework

The ESP-ADF also provides integration with Baidu DauerOS cloud services. A range of components is coming to provide integration with DeepBrain, Amazon, Google, Alibaba and Turing cloud services.

The ESP-ADF builds on well established, FreeRTOS based, Espressif IOT Development Framework ESP-IDF.

- Index

Provide feedback about this document

Read the Docs v: latest

Versions
  latest
  stable
  v2.0
  v1.0

Downloads
  pdf
  html

On Read the Docs
  Project Home
  Builds