Audio Development Framework¶

This is the documentation for Espressif Audio Development Framework.


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 by Espressif. Through a simple example, we would like to illustrate how to use ESP-ADF (Espressif Audio Development Framework).

To make the start with ESP-ADF quicker, Espressif designed development boards intended to build audio applications with the ESP32. Click the links below to get started.


Getting Started with ESP32-LyraT	Getting Started with ESP32-LyraTD-MSC

ESP32-LyraT V4.3 Getting Started Guide¶

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 BT audio speakers, speech-based remote controllers, smart-home appliances with audio functionality(ies), etc.

What You Need¶

1 × ESP32 LyraT V4.3 board
2 x 4-ohm speakers with Dupont female jumper wires or headphones with a 3.5 mm jack
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 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 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 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.
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 Overview

Left Speaker Output: Output socket to connect 4 ohm speaker. The pins have a standard 2.54 mm / 0.1” pitch.
Right Speaker Output: Output socket to connect 4 ohm speaker. The pins have a standard 2.54 mm / 0.1” 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 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 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:

Connect 4-ohm speakers to the Right and Left Speaker Output. Connecting headphones to the Headphone Output is an option.
Plug in the Micro-USB cables to the PC and to both USB ports of the ESP32 LyraT.
The Standby LED (green) should turn on. Assuming that a battery is not connected, the Charging LED (red) will blink every couple of seconds.
Toggle left the Power On Switch.
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¶

If the ESP32 LyraT is initially set up and checked, you can proceed with preparation of the development tools. Go to section Get Started, which will walk you through the following steps:

Setup ESP-IDF in your PC that provides a common framework to develop applications for the ESP32 in C language;
Get ESP-ADF to have the API specific for the audio applications;
Setup Path to ESP-ADF to make the framework aware of the audio specific API;
Start a Project that will provide a sample audio application for the ESP32-LyraT board;
Connect and Configure to prepare the application for loading;
Build, Flash and Monitor this will finally run the application and play some music.

Summary of Key Changes from LyraT V4.2¶

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-LyraTD-MSC V2.2 Getting Started Guide¶

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 4-ohm speakers with Dupont female jumper wires or headphones with a 3.5 mm jack
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-B, a MicroSemi Digital Signal Processing (DSP) chip, and a power management module.

ESP32-LyraTD-MSC Side View

The specific hardware includes:

ESP32-WROVER-B 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-B Module: The ESP32-WROVER-B module contains ESP32 chip to provide Wi-Fi / BT connectivity and data processing power as well as integrates 32 Mbit SPI flash and 64 Mbit 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 work with CTIA headsets. Please refer to Phone connector (audio) on Wikipedia.
Left Speaker Output: Output socket to connect 4 ohm speaker. The pins have a standard 2.54 mm / 0.1” pitch.
Right Speaker Output: Output socket to connect 4 ohm speaker. The pins have a standard 2.54 mm / 0.1” 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 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:

Connect 4-ohm speakers to the Right and Left Speaker Output. Connecting headphones to the Headphone Output is an option.
Plug in the Micro-USB cables to the PC and to both USB ports of the ESP32-LyraTD-MSC.
The Standby LED (green) should turn on. Assuming that a battery is not connected, the Charging LED (red) will blink every couple of seconds.
Toggle right the Power Switch.
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¶

If the ESP32-LyraTD-MSC is initially set up and checked, you can proceed with preparation of the development tools. Go to section Get Started, which will walk you through the following steps:

Setup ESP-IDF in your PC that provides a common framework to develop applications for the ESP32 in C language;
Get ESP-ADF to have the API specific for the audio applications;
Setup Path to ESP-ADF to make the framework aware of the audio specific API;
Start a Project that will provide a sample audio application for the ESP32-LyraTD-MSC board;
Connect and Configure to prepare the application for loading;
Build, Flash and Monitor this will finally run the application and play some music.

If you do not have one of the above boards, you can still use ESP-ADF for the ESP32 based audio applications. This is providing your board has a compatible audio codec or DSP chip, or you 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.

Setup ESP-IDF¶

Configure your PC according to ESP32 Documentation. Windows, Linux and Mac OS operating systems are supported.

You have a choice to compile and upload code to the ESP32 by command line with make or using Eclipse IDE.

Note

We are using ~/esp directory to install the toolchain, ESP-IDF, ESP-ADF and sample applications. You can use a different directory, but need to adjust respective commands.

To make the installation easier and less prone to errors, use the ~/esp default directory for the installation. Once you get through ESP-IDF setup and move to the ESP-ADF, you will notice that installation of the ESP-ADF follows the similar process. This should make it even easier to get up and running with the ESP-ADF.

If this is your first exposure to the ESP32 and ESP-IDF, then it is recommended to get familiar with hello_world and blink examples first. Once you can build, upload and run these two examples, then you are ready to proceed to the next section.

Get ESP-ADF¶

Having the ESP-IDF to compile, build and upload application for ESP32, you can now move to installing audio specific API / libraries. They are provided in ESP-ADF repository. To get it, open terminal, navigate to the directory to put the ESP-ADF, and clone it using git clone command:

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

ESP-ADF will be downloaded into ~/esp/esp-adf.

Note

Do not miss the --recursive option. If you have already cloned ESP-ADF without this option, run another command to get all the submodules:

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

Setup Path to ESP-ADF¶

The toolchain programs access ESP-ADF using ADF_PATH environment variable. This variable should be set up on your PC, otherwise the projects will not build. The process to set it up is analogous to setting up the IDF_PATH variable, please see instructions in ESP-IDF documentation under Add IDF_PATH to User Profile.

Start a Project¶

After initial preparation you are ready to build the first audio application for the ESP32. The process has already been described in ESP-IDF documentation. Now we would like to discuss again the key steps and show how the toolchain is able to access the ESP-ADF components by using the ADF_PATH variable.

Note

ESP-ADF is based on a specific release of the ESP-IDF. You will see this release cloned with ESP-ADF as a subdirectory, or more specifically as a submodule e.g. esp-idf @ ca3faa61 visible on the GitHub. Just follow this instruction and the build scripts will automatically reach ESP-IDF from the submodule.

To demonstrate how to build an application, we will use get-started/play_mp3 project from examples directory in the ADF.

Copy get-started/play_mp3 to ~/esp directory:

cd ~/esp
cp -r $ADF_PATH/examples/get-started/play_mp3 .

You can also find a range of example projects under the examples directory in the ESP-ADF repository. These example project directories can be copied in the same way as presented above, to begin your own projects.

Connect and Configure¶

Connect the audio ESP32 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.

At the terminal window, go to the directory of play_mp3 application and configure it with menuconfig by selecting the serial port, upload speed and the audio board version:

cd ~/esp/play_mp3
make menuconfig

Save the configuration.

Build, Flash and Monitor¶

Now you can build, upload and check the application. Run:

make flash monitor -j5

This will build the application including ESP-IDF / ESP-ADF components, upload (flash) binaries to your ESP32 board and start the monitor.

Upload¶

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 v2.1
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...
MONITOR
--- idf_monitor on /dev/ttyUSB0 115200 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---

Monitor¶

At this point press the Reset button to start the application. Following several lines of start up log, the play_mp3 application specific messages should be displayed:

...

I (303) PLAY_MP3_FLASH: [ 1 ] Start audio codec chip
I (323) PLAY_MP3_FLASH: [ 2 ] Create audio pipeline, add all elements to pipeline, and subscribe pipeline event
I (323) PLAY_MP3_FLASH: [2.1] Create mp3 decoder to decode mp3 file and set custom read callback
I (333) PLAY_MP3_FLASH: [2.2] Create i2s stream to write data to codec chip
I (343) PLAY_MP3_FLASH: [2.3] Register all elements to audio pipeline
I (353) PLAY_MP3_FLASH: [2.4] Link it together [mp3_music_read_cb]-->mp3_decoder-->i2s_stream-->[codec_chip]
I (363) PLAY_MP3_FLASH: [ 3 ] Setup event listener
I (363) PLAY_MP3_FLASH: [3.1] Listening event from all elements of pipeline
I (373) PLAY_MP3_FLASH: [ 4 ] Start audio_pipeline
W (373) AUDIO_ELEMENT: [mp3] RESUME:Element has not running,state:3,task_run:1
W (393) AUDIO_ELEMENT: [i2s] RESUME:Element has not running,state:3,task_run:1
I (403) PLAY_MP3_FLASH: [ * ] Receive music info from mp3 decoder, sample_rates=44100, bits=16, ch=2
W (433) AUDIO_ELEMENT: [i2s] RESUME:Element has not running,state:3,task_run:1
I (7183) PLAY_MP3_FLASH: [ 5 ] Stop audio_pipeline
W (7183) AUDIO_PIPELINE: There are no listener registered

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/Makefile and you should see

PROJECT_NAME := play_mp3
include $(ADF_PATH)/project.mk

The second line contains $ADF_PATH to point the toolchain to the ESP-ADF. You need similar Makefile in your own applications developed with the ESP-ADF.

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 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, Streams or Filters.

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 example.

Sample Organization of Elements in Audio Pipeline¶

The audio data is typically acquired using an input Stream, processed with Codecs and Filters, 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 a 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 avialable 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

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 retrieve by getdata.

Return

ESP_OK
ESP_FAIL

Parameters

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

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

el: The audio element handle
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

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

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

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

el: The audio element handle
uri: The uri pointer

char *audio_element_get_uri(audio_element_handle_t el)¶

Get audio element URI.

Return

URI pointer

Parameters

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

el: The audio element handle

esp_err_t audio_element_terminate(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

el: The audio element handle

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

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 until Element Task has done and exit.

Return

ESP_OK
ESP_FAIL

Parameters

el: The audio element handle

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

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 event 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.

ESP_FAIL

Return

ESP_OK

Parameters

el: The audio element handle
wait_for_rb_threshold: The wait for rb threshold (0 .. 1)
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_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 listene.

Return

ESP_OK
ESP_FAIL

Parameters

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

el: The audio element handle
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

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

el: The audio element handle
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

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

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

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

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

el: The audio element handle
size_expect: The size expect
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

el: The audio element handle
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

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

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

el: The audio element handle
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

el: The audio element handle
timeout: The timeout

esp_err_t audio_element_reset_input_ringbuf(audio_element_handle_t el)¶

Reset inputbuffer.

Return

ESP_OK
ESP_FAIL

Parameters

el: The audio element handle

esp_err_t audio_element_reset_output_ringbuf(audio_element_handle_t el)¶

Reset outputbuffer.

Return

ESP_OK
ESP_FAIL

Parameters

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 provice 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

el: The audio element handle
buffer: The buffer pointer
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

el: The audio element handle
buffer: The buffer pointer
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

el: The audio element handle
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.
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

el: The audio element
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.
context: An optional context which will be passed to callback function on every invocation

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

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

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

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

el: The audio element handle

esp_err_t 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_OK
ESP_ERR_INVALID_ARG

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

esp_err_t 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

ESP_OK
ESP_FAIL

Parameters

el: The audio element handle
buffer: The buffer pointer
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

el: The audio element handle
rb: The ringbuffer handle
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

el: The audio element handle
rb: The ringbuffer handle
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

el: The audio element handle
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

el: The audio element handle
index: Index of multi ringbuffer, starts from 0, should be less than NUMBER_OF_MULTI_RINGBUF

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

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 volume¶: Volume in percent

bool mute¶: Mute

int64_t byte_pos¶: The current position (in bytes) being processed for an element

int64_t total_bytes¶: The total bytes for an element

char *uri¶: URI (optional)

audio_codec_t codec_fmt¶: Music format (optional)

audio_element_reserve_data_t reserve_data¶: This value is reserved for user use

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

io_func open¶: Open callback function

io_func seek¶: Seek callback function

process_func process¶: Process callback function

io_func close¶: Close callback function

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

char *tag¶: Element tag

bool enable_multi_io¶: Enable multi input and 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 (*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)¶

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¶

AEL_STATE_RUNNING¶

AEL_STATE_PAUSED¶

AEL_STATE_STOPPED¶

AEL_STATE_FINISHED¶

AEL_STATE_ERROR¶

enum audio_element_msg_cmd_t¶

Audio element action command, process on dispatcher

Values:

AEL_MSG_CMD_NONE = 0¶

AEL_MSG_CMD_ERROR = 1¶

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¶

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_MOUNTED = 15¶

AEL_STATUS_UNMOUNTED = 16¶

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

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

Return

ESP_OK on success
ESP_FAIL when any errors

Parameters

pipeline: The Audio Pipeline Handle
el: The Audio Element Handle
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

pipeline: The Audio Pipeline Handle
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

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

pipeline: The Audio Pipeline Handle

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

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

pipeline: The Audio Pipeline Handle

esp_err_t audio_pipeline_stop(audio_pipeline_handle_t pipeline)¶

Stop all elements and clear information of items. Free up memory for all task items. The link state of the elements in the pipeline is kept, events are still registered, but the audio_pipeline_pause and audio_pipeline_resume functions have no effect. To restart audio_pipeline, use the audio_pipeline_resume function.

Return

ESP_OK on success
ESP_FAIL when any errors

Parameters

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 until all the Elements in the pipeline actually stop.

Return

ESP_OK on success
ESP_FAIL when any errors

Parameters

pipeline: The Audio Pipeline Handle

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

pipeline: The Audio Pipeline Handle
link_tag: Array of element name was registered by audio_pipeline_register
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

pipeline: The Audio Pipeline Handle

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

Find element from registered pipeline by tag.

Return

NULL when any errors
Others on success

Parameters

pipeline: The Audio Pipeline Handle
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

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

pipeline: The Audio Pipeline Handle
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

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

pipeline: The audio pipeline handle
first: Previous element is first input element, need to set true
prev: Previous element
conect_rb: Connect ring buffer
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

pipeline: The audio pipeline handle
element_1: The element to add to the audio_pipeline.
...: 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

pipeline: The audio pipeline handle
element_1: The element to add to the audio_pipeline.
...: 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

pipeline: The audio pipeline handle
element_1: The element to add to the audio_pipeline.
...: 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

pipeline: The audio pipeline handle
element_1: The element event to subscribe to the audio_pipeline.
...: 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

pipeline: The audio pipeline handle
dest_el: Destination element
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

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

pipeline: The Audio Pipeline 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 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

pipeline: The audio pipeline handle
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

pipeline: The Audio Pipeline Handle
link_tag: Array of elements name that was registered by audio_pipeline_register
link_num: Total number of elements of the link_tag array

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.

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
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

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

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

evt: The event interface
msg: The pointer to structure in which event is to be received
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

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¶

enum audio_codec_t¶

Values:

AUDIO_CODEC_NONE = 0¶

AUDIO_CODEC_RAW¶

AUDIO_CODEC_WAV¶

AUDIO_CODEC_MP3¶

AUDIO_CODEC_AAC¶

AUDIO_CODEC_OPUS¶

AUDIO_PLAYLIST¶

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

Macros¶

ESP_ERR_AUDIO_BASE¶: Starting number of ESP audio error codes

Type Definitions¶

typedef enum audio_err_t audio_err_t¶

typedef enum esp_audio_status_t esp_audio_status_t¶

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_UNKNOWN = ESP_ERR_AUDIO_BASE + 13¶

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_STOPED = 3¶

AUDIO_STATUS_ERROR = 4¶

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 untill is finished

TERMINATION_TYPE_MAX¶

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

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

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_ALREADY_EXISTS: in_stream has already exist or have the same stream tag.

Parameters

handle: The esp_audio instance
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_ALREADY_EXISTS: out_stream has already exist or have the same stream tag.

Parameters

handle: The esp_audio instance
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_ALREADY_EXISTS: lib has already exist or have the same extension.

Parameters

handle: The esp_audio instance
type: The audio codec type(encoder or decoder)
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

handle: The esp_audio instance
type: The CODEC_ENCODER or CODEC_DECODER
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”

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.

Return

ESP_ERR_AUDIO_NO_ERROR: on succss
ESP_ERR_AUDIO_TIMEOUT: timeout the play activity.
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”,
type: Specific handle type decoder or encoder
pos: Specific starting position by bytes

audio_err_t esp_audio_stop(esp_audio_handle_t handle, audio_termination_type_t type)¶

Stop the esp_audio.

Note

If user queue has been registered by evt_que, AUDIO_STATUS_STOPED event for success or AUDIO_STATUS_ERROR event for error will be received. TERMINATION_TYPE_DONE only works with input stream which can’t stoped by itself, e.g. raw read/write stream, others streams are no effect.

Return

ESP_ERR_AUDIO_NO_ERROR: on succss
ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments
ESP_ERR_AUDIO_TIMEOUT: timeout the stop activity.

Parameters

handle: The esp_audio instance
type: Stop immediately or done

audio_err_t esp_audio_pause(esp_audio_handle_t handle)¶

Pause the esp_audio.

Note

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.

Return

ESP_ERR_AUDIO_NO_ERROR: on succss
ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments
ESP_ERR_AUDIO_TIMEOUT: timeout the pause activity.

Parameters

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_PLAYING event for success or AUDIO_STATUS_ERROR event for error will be received.

Return

ESP_ERR_AUDIO_NO_ERROR: on succss
ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments
ESP_ERR_AUDIO_TIMEOUT: timeout the resume activity.

Parameters

handle: The esp_audio instance

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 succss
ESP_ERR_AUDIO_CTRL_HAL_FAIL: error with hardware.
ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

Parameters

handle: The esp_audio instance
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 succss
ESP_ERR_AUDIO_CTRL_HAL_FAIL: error with hardware.
ESP_ERR_AUDIO_INVALID_PARAMETER: invalid arguments

Parameters

handle: The esp_audio instance
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 succss
ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance or esp_audio does not playing

Parameters

handle: The esp_audio instance
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 succss
ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance
ESP_ERR_AUDIO_NOT_READY:no out stream.

Parameters

handle: The esp_audio instance
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 succss
ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance
ESP_ERR_AUDIO_NOT_READY:no out stream.

Parameters

handle: The esp_audio instance
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 succss
ESP_ERR_AUDIO_INVALID_PARAMETER: no esp_audio instance
ESP_ERR_AUDIO_MEMORY_LACK: allocate memory fail

Parameters

handle: The esp_audio instance
sets: A pointer to esp_audio_setup_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 rsample;others:44.1K,48K,32K,16K,8K has supported

audio_hal_handle_t hal¶: Codec IC hardware handle

QueueHandle_t evt_que¶: For received esp_audio events (optional)

int task_prio¶: esp_audio task priority

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

char *set_path¶: Set out stream path

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

Type Definitions¶

typedef void *esp_audio_handle_t¶

typedef struct esp_audio_cfg_t esp_audio_cfg_t¶: esp_audio configuration parameters

typedef struct esp_audio_setup_t esp_audio_setup_t¶: esp_audio setup parameters by manual

Audio Streams¶

An Audio Element responsible for acquiring of audio data and then sending the data out after processing, is called the Audio Stream.

The following stream types are supported:

I2S Stream
HTTP Stream
FatFs Stream
Raw Stream
Spiffs Stream

To set the stream type, use provided structure, e.g. i2s_stream_cfg_t for I2S stream, together with audio_stream_type_t enumerator.

See description below for the API details.

I2S Stream¶

When the I2S stream type is “writer”, the data may be sent either to a codec chip or to the internal DAC of ESP32. To simplify configuration, two macros are provided to cover each case:

I2S_STREAM_CFG_DEFAULT - the I2S stream is communicating with a codec chip
I2S_STREAM_INTERNAL_DAC_CFG_DEFAULT - the stream data are sent to the DAC

Each macro configures several other stream parameters such as sample rate, bits per sample, DMA buffer length, etc.

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_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

i2s_stream: The i2s element handle
rate: Clock rate (in Hz)
bits: Audio bit width (8, 16, 24, 32)
ch: Number of Audio channels (1: Mono, 2: Stereo)

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_config_t i2s_config¶: I2S driver configurations

i2s_pin_config_t i2s_pin_config¶: I2S driver hardware pin configurations

i2s_port_t i2s_port¶: I2S driver hardware port

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)

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_INTERNAL_DAC_CFG_DEFAULT¶

HTTP Stream¶

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)¶

esp_err_t http_stream_restart(audio_element_handle_t el)¶

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)

http_stream_event_handle_t event_handle¶: The hook function for HTTP Stream

void *user_data¶: User data context

bool enable_playlist_parser¶: Enable playlist parser

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¶

FatFs Stream¶

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)

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¶

Raw Stream¶

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¶

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)

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¶

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)

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 AMRNB and AMRWB formats.

Application Examples¶

Implementation of this API is demonstrated in the following examples:

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)

Macros¶

AMR_DECODER_TASK_STACK_SIZE¶

AMR_DECODER_TASK_CORE¶

AMR_DECODER_TASK_PRIO¶

AMR_DECODER_RINGBUFFER_SIZE¶

DEFAULT_AMR_DECODER_CONFIG¶

API Reference - AMRNB Encoder¶

Header File¶

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

Functions¶

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)

Macros¶

AMRNB_ENCODER_TASK_STACK¶

AMRNB_ENCODER_TASK_CORE¶

AMRNB_ENCODER_TASK_PRIO¶

AMRNB_ENCODER_RINGBUFFER_SIZE¶

DEFAULT_AMRNB_ENCODER_CONFIG¶

API Reference - AMRWB Encoder¶

Header File¶

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

Functions¶

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)

Macros¶

AMRWB_ENCODER_TASK_STACK¶

AMRWB_ENCODER_TASK_CORE¶

AMRWB_ENCODER_TASK_PRIO¶

AMRWB_ENCODER_RINGBUFFER_SIZE¶

DEFAULT_AMRWB_ENCODER_CONFIG¶

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)

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:

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

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)

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)

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)

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:

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)

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)

Macros¶

WAV_ENCODER_TASK_STACK¶

WAV_ENCODER_TASK_CORE¶

WAV_ENCODER_TASK_PRIO¶

WAV_ENCODER_RINGBUFFER_SIZE¶

DEFAULT_WAV_ENCODER_CONFIG¶

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.

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.

Return

ESP_OK ESP_FAIL

Parameters

self: Audio element handle
src_rate: The sample rate of stream data
src_ch: The number channels 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 audio_codec_type_t is AUDIO_CODEC_TYPE_DECODER, src_rate and src_ch will be fetched from audio_element_getinfo.
If the audio_codec_type_t is AUDIO_CODEC_TYPE_ENCODER, 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_ch¶: The number of channel(s) of the destination PCM file (Mono=1, Dual=2)

int sample_bits¶: The bit width of the PCM file. Currently, the only supported bit width is 16 bits.

int 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.

int 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: 0~4; O indicates the lowest complexity, which means the accuracy is the lowest and the speed is the fastest; Meanwhile, 4 indicates the highest complexity, which means the accuracy is the highest and the speed is the slowest.

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.

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

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¶

Services¶

To interface an ESP32 based audio device with external physical or virtual devices, like a Bluetooth speaker or a cloud server, the ADF provides services. A service is a software implementation of specific protocol to facilitate communication between devices. Usually it also covers a set of functionalities to execute specific operations that involve either one or both devices, e.g. muting a Bluetooth speaker during playback or recognizing voice commands to adjust the color temperature of light in a room. The service may also provide polices to allow device operation by specific user or application.

For details please refer to descriptions listed below.

Bluetooth Service¶

This service is dedicated to interface with Bluetooth devices and provides:

A2DP (Advanced Audio Distribution Profile), that implements 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¶

audio_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

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

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

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

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

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

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

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

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

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

periph: The periph
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

Structures¶

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

Macros¶

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

enum periph_bluetooth_event_id_t¶

brief Bluetooth peripheral event id

Values:

PERIPH_BLUETOOTH_UNKNOWN = 0¶: No event

PERIPH_BLUETOOTH_CONNECTED¶: A bluetooth device was connected

PERIPH_BLUETOOTH_DISCONNECTED¶: Last connection was disconnected

PERIPH_BLUETOOTH_AUDIO_STARTED¶: The audio session has been started

PERIPH_BLUETOOTH_AUDIO_SUSPENDED¶: The audio session has been suspended

PERIPH_BLUETOOTH_AUDIO_STOPPED¶: The audio session has been stopped

Header File¶

audio_service/include/bt_keycontrol.h

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¶

#include "esp_log.h"
#include "esp_peripherals.h"
#include "periph_sdcard.h"
#include "periph_button.h"
#include "periph_touch.h"

static const char *TAG = "ESP_PERIPH_TEST";

static esp_err_t _periph_event_handle(audio_event_iface_msg_t *event, void *context)
{
    switch ((int)event->source_type) {
        case PERIPH_ID_BUTTON:
            ESP_LOGI(TAG, "BUTTON[%d], event->event_id=%d", (int)event->data, event->cmd);
            break;
        case PERIPH_ID_SDCARD:
            ESP_LOGI(TAG, "SDCARD status, event->event_id=%d", event->cmd);
            break;
        case PERIPH_ID_TOUCH:
            ESP_LOGI(TAG, "TOUCH[%d], event->event_id=%d", (int)event->data, event->cmd);
            break;
        case PERIPH_ID_WIFI:
            ESP_LOGI(TAG, "WIFI, event->event_id=%d", event->cmd);
            break;
    }
    return ESP_OK;
}

void app_main(void)
{
    // Initialize Peripherals pool
    esp_periph_config_t periph_cfg = {
        .event_handle = _periph_event_handle,
        .user_context = NULL,
    };
    esp_periph_init(&periph_cfg);

    // Setup SDCARD peripheral
    periph_sdcard_cfg_t sdcard_cfg = {
        .root = "/sdcard",
        .card_detect_pin = GPIO_NUM_34,
    };
    esp_periph_handle_t sdcard_handle = periph_sdcard_init(&sdcard_cfg);

    // Setup BUTTON peripheral
    periph_button_cfg_t btn_cfg = {
        .gpio_mask = GPIO_SEL_36 | GPIO_SEL_39
    };
    esp_periph_handle_t button_handle = periph_button_init(&btn_cfg);

    // Setup TOUCH peripheral
    periph_touch_cfg_t touch_cfg = {
        .touch_mask = TOUCH_PAD_SEL4 | TOUCH_PAD_SEL7 | TOUCH_PAD_SEL8 | TOUCH_PAD_SEL9,
        .tap_threshold_percent = 70,
    };
    esp_periph_handle_t touch_handle = periph_touch_init(&touch_cfg);

    // Start all peripheral
    esp_periph_start(button_handle);
    esp_periph_start(sdcard_handle);
    esp_periph_start(touch_handle);
    vTaskDelay(10*1000/portTICK_RATE_MS);

    //Stop button peripheral
    esp_periph_stop(button_handle);
    vTaskDelay(10*1000/portTICK_RATE_MS);

    //Start button again
    esp_periph_start(button_handle);
    vTaskDelay(10*1000/portTICK_RATE_MS);

    //Stop & destroy all peripherals
    esp_periph_destroy();
}

API Reference¶

Header File¶

esp_peripherals/include/esp_peripherals.h

Functions¶

esp_err_t esp_periph_init(esp_periph_config_t *config)¶

brief Initialize esp_peripherals, create empty peripherals list. Call this function only 1 time, before esp_periph_start any peripherals. 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

ESP_OK
ESP_FAIL

Parameters

config: The configurations

esp_err_t esp_periph_start(esp_periph_handle_t periph)¶

Add the Peripheral to peripherals list, enable and start monitor task (if not)

Note

This peripheral must be created by esp_periph_create

Return

ESP_OK on success
ESP_FAIL when any errors

Parameters

periph: The peripheral

esp_err_t esp_periph_stop(esp_periph_handle_t periph)¶

Stop monitor the peripheral, the peripheral state still kept. This funciton only temporary disables the peripheral.

Return

ESP_OK
ESP_FAIL

Parameters

periph: The periph

esp_err_t esp_periph_stop_all()¶

Stop monitor all peripherals, the peripheral state still kept. This funciton only temporary disables the peripheral.

Return

ESP_OK
ESP_FAIL

esp_err_t esp_periph_destroy()¶

This function will stop and kill the monitor task, calling all destroy callback functions of peripheral (so you do not need to destroy the peripheral object manually). And also to remove all memory allocated to the peripherals list, you need to call the esp_periph_init function again if you want to use it.

Return

ESP_OK
ESP_FAIL

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

periph: The handle of peripheral

esp_periph_handle_t esp_periph_get_by_id(int periph_id)¶

Get the peripheral handle by Peripheral ID.

Return

The esp_periph_handle_t

Parameters

periph_id: as esp_periph_id_t, or any ID you use when call esp_periph_create

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

periph: The periph
event_id: The event identifier
data: The data
data_len: The data length

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

periph: The periph
cmd: The command
data: The data
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

periph: The periph
cmd: The command
data: The data
data_len: The data length

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

periph: The periph
data: The data

void *esp_periph_get_data(esp_periph_handle_t periph)¶

Get the userdata stored in the peripheral.

Return

Peripheral data pointer

Parameters

periph: The periph

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

periph: The periph
interval_tick: The interval tick
callback: The callback

esp_err_t esp_periph_stop_timer(esp_periph_handle_t periph)¶

Stop peripheral timer.

Return

ESP_OK
ESP_FAIL

Parameters

periph: The periph

QueueHandle_t esp_periph_get_queue()¶

Peripheral using event_iface to control the event, all events send out to event_iface queue. But in case we want to read events directly from the event_iface queue, this function will be useful.

Return: The queue handle

esp_periph_id_t esp_periph_get_id(esp_periph_handle_t periph)¶

Get Peripheral Identify.

Return

The peripheral identify

Parameters

periph: The periph

esp_err_t esp_periph_set_id(esp_periph_handle_t periph, esp_periph_id_t periph_id)¶

Set Peripheral identify.

Return

ESP_OK
ESP_FAIL

Parameters

periph: The periph
periph_id: The periph identifier

audio_event_iface_handle_t esp_periph_get_event_iface()¶

Return the event_iface used by this esp_peripherals.

Return: The audio event iface handle

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

periph_id: The periph identifier
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 operation from initialization, execution of commands to destroy, functions assigned by this function.

Return

ESP_OK
ESP_FAIL

Parameters

periph: The periph
init: The initialize
run: The run
destroy: The destroy

long long esp_periph_tick_get()¶

Get tick in milliseconds (from ESP32 boot)

Return: Tick in milliseconds

esp_err_t esp_periph_set_callback(esp_periph_event_handle_t cb)¶

Set event callback function.

Return

ESP_OK
ESP_FAIL

Structures¶

struct esp_periph_config_t¶

Common peripherals configurations.

Public Members

void *user_context¶: peripherals context data

esp_periph_event_handle_t event_handle¶: The Peripheral events handle

Macros¶

periph_tick_get¶

Type Definitions¶

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)¶

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¶

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

periph: The periph
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

periph: The periph

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

periph: The periph
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

periph: The periph
tick_to_wait: The tick to wait

Structures¶

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

const char *ssid¶: SSID of target AP

const char *password¶: password of target AP

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:

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

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

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

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 filter/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

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¶#include "freertos/FreeRTOS.h"
#include "esp_log.h"
#include "esp_peripherals.h"
#include "periph_console.h"

static const char *TAG = "ESP_PERIPH_TEST";

static esp_err_t _periph_event_handle(audio_event_iface_msg_t *event, void *context)
{
    switch ((int)event->source_type) {
        case PERIPH_ID_CONSOLE:
            ESP_LOGI(TAG, "CONSOLE, command id=%d", event->cmd);
            break;
    }
    return ESP_OK;
}

esp_err_t console_test_cb(esp_periph_handle_t periph, int argc, char *argv[])
{
    int i;
    ESP_LOGI(TAG, "CONSOLE Callback, argc=%d", argc);
    for (i=0; i<argc; i++) {
        ESP_LOGI(TAG, "CONSOLE Args[%d] %s", i, argv[i]);
    }
    return ESP_OK;
}

void app_main(void)
{
    // Initialize Peripherals pool
    esp_periph_config_t periph_cfg = {
        .event_handle = _periph_event_handle,
        .user_context = NULL,
    };
    esp_periph_init(&periph_cfg);

    const periph_console_cmd_t cmd[]= {
        { .cmd = "play", .id = 1, .help = "Play audio" },
        { .cmd = "stop", .id = 2, .help = "Stop audio" },
        { .cmd = "test", .help = "test console", .func = console_test_cb },
    };

    periph_console_cfg_t console_cfg = {
        .command_num = sizeof(cmd)/sizeof(periph_console_cmd_t),
        .commands = cmd,
    };
    esp_periph_handle_t console_handle = periph_console_init(&console_cfg);
    esp_periph_start(console_handle);
    vTaskDelay(30000/portTICK_RATE_MS);
    ESP_LOGI(TAG, "Stopped");
    esp_periph_destroy();

}

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

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_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 sepecifc 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 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 recorder/pipeline_raw_http 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:

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)¶

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

periph: The LED periph
gpio_num: The gpio number
time_on_ms: The time on milliseconds
time_off_ms: The time off milliseconds
fade: Fading enabled
loop: Loop

esp_err_t periph_led_stop(esp_periph_handle_t periph, int gpio_num)¶

Stop Blink the LED.

Return

ESP_OK
ESP_FAIL

Parameters

periph: The periph
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)

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

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_msc_adc_button

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

Macros¶

ADC_DEFAULT_ARR¶

Enumerations¶

enum periph_adc_button_event_id_t¶

Values:

PERIPH_ADC_BUTTON_IDLE¶

PERIPH_ADC_BUTTON_CLICK¶

PERIPH_ADC_BUTTON_PRESS¶

PERIPH_ADC_BUTTON_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_msc_leds 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_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_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

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¶

Enumerations¶

enum periph_is31fl3216_state_t¶

Values:

IS31FL3216_STATE_OFF¶

IS31FL3216_STATE_ON¶

IS31FL3216_STATE_FLASH¶

IS31FL3216_STATE_BY_AUDIO¶

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/element_sdcard_mp3 example.

API Reference¶

Header File¶

audio_pipeline/include/ringbuf.h

Functions¶

ringbuf_handle_t rb_create(int size, int block_size)¶

Create ringbuffer with total size = size * block_size.

Return

ringbuf_handle_t

Parameters

size: The size
block_size: The block size

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

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

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

rb: The Ringbuffer handle

int rb_bytes_available(ringbuf_handle_t rb)¶

Get total bytes available of Ringbuffer.

Return

total bytes available

Parameters

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

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

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

Return

Number of bytes read

Parameters

rb: The Ringbuffer handle
buf: The buffer pointer to read out data
len: The length request
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

rb: The Ringbuffer handle
buf: The buffer
len: The length
ticks_to_wait: The ticks to wait

int rb_size_get(ringbuf_handle_t rb)¶

Get total size of ringbuffer.

Return

Total size of ringbuffer (in block byte(s))

Parameters

rb: The Ringbuffer handle

esp_err_t rb_done_write(ringbuf_handle_t rb)¶

Set status of writing to ringbuffer is done.

Return

ESP_OK
ESP_FAIL

Parameters

rb: The Ringbuffer handle

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, int index)¶

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
index: Indicates which codec will be initialized

esp_err_t audio_hal_deinit(audio_hal_handle_t audio_hal, int index)¶

Uninitialize media codec driver.

Return

int, 0success, othersfail

Parameters

audio_hal: reference function pointer for selected audio codec
index: Indicates which codec will be deinitialized

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_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(%)

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

Macros¶

AUDIO_HAL_VOL_DEFAULT¶

AUDIO_HAL_ES8388_DEFAULT¶

AUDIO_HAL_ES8374_DEFAULT¶

Type Definitions¶

typedef struct audio_hal *audio_hal_handle_t¶

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

*volume: voice volume (0~100)

esp_err_t es8388_set_voice_mute(int enable)¶

Configure ES8388 DAC mute or not. Basically you can use this function to mute the output or not.

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

-1 Parameter error
0 voice mute disable
1 voice mute enable

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

void es8388_pa_power(bool enable)¶

Set ES8388 PA power.

Return

void

Parameters

enable: true for enable PA power, false for disable PA power

Structures¶

struct es_i2s_clock_t¶

Configure ES8388 clock.

Public Members

es_sclk_div_t sclk_div¶: bits clock divide

es_lclk_div_t lclk_div¶: WS clock divide

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¶

Enumerations¶

enum es_bits_length_t¶

Values:

BIT_LENGTH_MIN = -1¶

BIT_LENGTH_16BITS = 0x03¶

BIT_LENGTH_18BITS = 0x02¶

BIT_LENGTH_20BITS = 0x01¶

BIT_LENGTH_24BITS = 0x00¶

BIT_LENGTH_32BITS = 0x04¶

BIT_LENGTH_MAX¶

enum es_sclk_div_t¶

Values:

MCLK_DIV_MIN = -1¶

MCLK_DIV_1 = 1¶

MCLK_DIV_2 = 2¶

MCLK_DIV_3 = 3¶

MCLK_DIV_4 = 4¶

MCLK_DIV_6 = 5¶

MCLK_DIV_8 = 6¶

MCLK_DIV_9 = 7¶

MCLK_DIV_11 = 8¶

MCLK_DIV_12 = 9¶

MCLK_DIV_16 = 10¶

MCLK_DIV_18 = 11¶

MCLK_DIV_22 = 12¶

MCLK_DIV_24 = 13¶

MCLK_DIV_33 = 14¶

MCLK_DIV_36 = 15¶

MCLK_DIV_44 = 16¶

MCLK_DIV_48 = 17¶

MCLK_DIV_66 = 18¶

MCLK_DIV_72 = 19¶

MCLK_DIV_5 = 20¶

MCLK_DIV_10 = 21¶

MCLK_DIV_15 = 22¶

MCLK_DIV_17 = 23¶

MCLK_DIV_20 = 24¶

MCLK_DIV_25 = 25¶

MCLK_DIV_30 = 26¶

MCLK_DIV_32 = 27¶

MCLK_DIV_34 = 28¶

MCLK_DIV_7 = 29¶

MCLK_DIV_13 = 30¶

MCLK_DIV_14 = 31¶

MCLK_DIV_MAX¶

enum es_lclk_div_t¶

Values:

LCLK_DIV_MIN = -1¶

LCLK_DIV_128 = 0¶

LCLK_DIV_192 = 1¶

LCLK_DIV_256 = 2¶

LCLK_DIV_384 = 3¶

LCLK_DIV_512 = 4¶

LCLK_DIV_576 = 5¶

LCLK_DIV_768 = 6¶

LCLK_DIV_1024 = 7¶

LCLK_DIV_1152 = 8¶

LCLK_DIV_1408 = 9¶

LCLK_DIV_1536 = 10¶

LCLK_DIV_2112 = 11¶

LCLK_DIV_2304 = 12¶

LCLK_DIV_125 = 16¶

LCLK_DIV_136 = 17¶

LCLK_DIV_250 = 18¶

LCLK_DIV_272 = 19¶

LCLK_DIV_375 = 20¶

LCLK_DIV_500 = 21¶

LCLK_DIV_544 = 22¶

LCLK_DIV_750 = 23¶

LCLK_DIV_1000 = 24¶

LCLK_DIV_1088 = 25¶

LCLK_DIV_1496 = 26¶

LCLK_DIV_1500 = 27¶

LCLK_DIV_MAX¶

enum es_d2se_pga_t¶

Values:

D2SE_PGA_GAIN_MIN = -1¶

D2SE_PGA_GAIN_DIS = 0¶

D2SE_PGA_GAIN_EN = 1¶

D2SE_PGA_GAIN_MAX =2¶

enum es_adc_input_t¶

Values:

ADC_INPUT_MIN = -1¶

ADC_INPUT_LINPUT1_RINPUT1 = 0x00¶

ADC_INPUT_MIC1 = 0x05¶

ADC_INPUT_MIC2 = 0x06¶

ADC_INPUT_LINPUT2_RINPUT2 = 0x50¶

ADC_INPUT_DIFFERENCE = 0xf0¶

ADC_INPUT_MAX¶

enum es_dac_output_t¶

Values:

DAC_OUTPUT_MIN = -1¶

DAC_OUTPUT_LOUT1 = 0x04¶

DAC_OUTPUT_LOUT2 = 0x08¶

DAC_OUTPUT_SPK = 0x09¶

DAC_OUTPUT_ROUT1 = 0x10¶

DAC_OUTPUT_ROUT2 = 0x20¶

DAC_OUTPUT_ALL = 0x3c¶

DAC_OUTPUT_MAX¶

enum es_mic_gain_t¶

Values:

MIC_GAIN_MIN = -1¶

MIC_GAIN_0DB = 0¶

MIC_GAIN_3DB = 3¶

MIC_GAIN_6DB = 6¶

MIC_GAIN_9DB = 9¶

MIC_GAIN_12DB = 12¶

MIC_GAIN_15DB = 15¶

MIC_GAIN_18DB = 18¶

MIC_GAIN_21DB = 21¶

MIC_GAIN_24DB = 24¶

MIC_GAIN_MAX¶

enum es_module_t¶

Values:

ES_MODULE_MIN = -1¶

ES_MODULE_ADC = 0x01¶

ES_MODULE_DAC = 0x02¶

ES_MODULE_ADC_DAC = 0x03¶

ES_MODULE_LINE = 0x04¶

ES_MODULE_MAX¶

enum es_mode_t¶

Values:

ES_MODE_MIN = -1¶

ES_MODE_SLAVE = 0x00¶

ES_MODE_MASTER = 0x01¶

ES_MODE_MAX¶

enum es_i2s_fmt_t¶

Values:

ES_I2S_MIN = -1¶

ES_I2S_NORMAL = 0¶

ES_I2S_LEFT = 1¶

ES_I2S_RIGHT = 2¶

ES_I2S_DSP = 3¶

ES_I2S_MAX¶

ES8374 Driver¶

Driver for ES8374 codec chip.

API Reference¶

Header File¶

audio_hal/driver/es8374/es8374.h

Functions¶

esp_err_t es8374_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_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_set_voice_volume(int volume)¶

Set voice volume.

Return

ESP_OK
ESP_FAIL

Parameters

volume: voice volume (0~100)

esp_err_t es8374_get_voice_volume(int *volume)¶

Get voice volume.

Return

ESP_OK
ESP_FAIL

Parameters

*volume: voice volume (0~100)

esp_err_t es8374_set_voice_mute(int 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

-1: Parameter error
0: Voice is unmuted
1: Voice is muted

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_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_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

void es8374_pa_power(bool enable)¶

Set ES8374 PA power.

Return

void

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_init(audio_hal_codec_config_t *cfg)¶

Initialize ZL38063 chip.

Return

ESP_OK
ESP_FAIL

Parameters

cfg: configuration of ZL38063

esp_err_t zl38063_deinit(void)¶

Deinitialize ZL38063 chip.

Return

ESP_OK
ESP_FAIL

esp_err_t zl38063_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_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_set_voice_volume(int volume)¶

Set voice volume.

Return

ESP_OK
ESP_FAIL

Parameters

volume: voice volume (0~100)

esp_err_t zl38063_get_voice_volume(int *volume)¶

Get voice volume.

Return

ESP_OK
ESP_FAIL

Parameters

*volume: voice volume (0~100)

Macros¶

AUDIO_HAL_ZL38063_DEFAULT¶

Configuration Options¶

Compile-time configuration options specific to ESP-ADF.

ESP HTTP client¶

ESP_HTTP_CLIENT_ENABLE_HTTPS¶

Enable https

Found in: Component config > ESP HTTP client

This option will enable https protocol by linking mbedtls library and initializing SSL transport

Audio HAL¶

AUDIO_BOARD¶

Audio board

Found in: Audio HAL

Select an audio board to use with the ESP-ADF

Available options:

ESP_LYRAT_V4_3_BOARD

ESP_LYRAT_V4_2_BOARD

ESP_LYRATD_MSC_V2_1_BOARD

ESP_LYRATD_MSC_V2_2_BOARD

Speech Recognition Configuration¶

SR_MODEL_SEL¶

Speech recognition wake net to use

Found in: Speech Recognition Configuration

Select the wake net to be used.

Available options:

SR_MODEL_WN3_QUANT

SR_MODEL_WN4_QUANT

NAME_OF_WAKEUP_WORD¶

Name of wakeup word

Found in: Speech Recognition Configuration

Select wakeup word

Available options:

WAKEUP_WORD_HI_LEXIN

WAKEUP_WORD_ALEXA

WAKEUP_WORD_LIGHT_CONTROL_CN

WAKEUP_WORD_SPEECH_CMD_CH

HTTP Server¶

HTTPD_MAX_REQ_HDR_LEN¶

Max HTTP Request Header Length

Found in: Component config > HTTP Server

This sets the maximum supported size of headers section in HTTP request packet to be processed by the server

HTTPD_MAX_URI_LEN¶

Max HTTP URI Length

Found in: Component config > HTTP Server

This sets the maximum supported size of HTTP request URI to be processed by the server

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¶

When designing a project with ability to process an audio signal 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 them
WI-Fi interface to obtain an audio data stream from the internet
Bluetooth interface to obtain an audio data stream from e.g. a BT 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 and amplifier with 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 BT 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 ESP32 has all the above features or is able to support them (e.g. can drive Ethernet PHY). Considering the ESP32 cost is about $3, 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 couple of examples.

Project Minimum¶

With several peripherals on ESP32, 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 minumum 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 additional memory may be required. For such cases consider using ESP32-WROVER that provides 4 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
Component	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

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]
Depending on value of SD_CARD_OPEN_FILE_NUM_MAX in audio_hal/board/board.h, that is then used in sd_card_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]
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]
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¶

All of Streams and Codecs based on audio element.
All events based on queue.
Audio pipeline supports dynamic combination.
Audio pipeline supports multiple elements.
Pipeline Support functionality plug-in.
Audio common peripherals support work in the one task.
Support post-event mechanism in peripherals.
Support high level audio play API based on element and audio pipeline.
Audio high level interface supports dynamic adding of codec library.
Audio high level interface supports dynamic adding of input and output stream.
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¶

audio_element_handle_t el;
audio_element_cfg_t cfg = DEFAULT_AUDIO_ELEMENT_CONFIG();
cfg.open = _el_open;
cfg.read = _el_read;
cfg.process = _el_process;
cfg.write = _el_write;
cfg.close = _el_close;
el = audio_element_init(&cfg);
TEST_ASSERT_NOT_NULL(el);
TEST_ASSERT_EQUAL(ESP_OK, audio_element_start(el));

Audio Event¶

Example¶

audio_event_handle_t evt1;
audio_event_cfg_t cfg = AUDIO_EVENT_IFACE_DEFAULT_CFG();
cfg.dispatcher = evt_process;
cfg.queue_size = 10;
cfg.context = &evt1;
cfg.type = AUDIO_EVENT_TYPE_ELEMENT;
evt1 = audio_event_init(&cfg);
TEST_ASSERT_NOT_NULL(evt1);

audio_event_msg_t msg;
int i;
ESP_LOGI(TAG, "[✓] dispatch 10 msg to evt1");
for (i = 0; i < 10; i++) {
    msg.cmd = i;
    TEST_ASSERT_EQUAL(ESP_OK, audio_event_dispatch(evt1, &msg));
}
msg.cmd = 10;
TEST_ASSERT_EQUAL(ESP_FAIL, audio_event_dispatch(evt1, &msg));
ESP_LOGI(TAG, "[✓] listening 10 event have dispatched fron evt1");
while (audio_event_listen(evt1) == ESP_OK);

Audio Pipeline¶

Example¶

audio_element_handle_t first_el, mid_el, last_el;
audio_element_cfg_t el_cfg = DEFAULT_AUDIO_ELEMENT_CONFIG();

el_cfg.open = _el_open;
el_cfg.read = _el_read;
el_cfg.process = _el_process;
el_cfg.close = _el_close;
first_el = audio_element_init(&el_cfg, "first");
TEST_ASSERT_NOT_NULL(first_el);

el_cfg.read = NULL;
el_cfg.write = NULL;
mid_el = audio_element_init(&el_cfg, "mid");
TEST_ASSERT_NOT_NULL(mid_el);
el_cfg.write = _el_write;
last_el = audio_element_init(&el_cfg, "last");
TEST_ASSERT_NOT_NULL(last_el);

audio_pipeline_cfg_t pipeline_cfg = DEFAULT_AUDIO_PIPELINE_CONFIG();
audio_pipeline_handle_t pipeline = audio_pipeline_init(&pipeline_cfg);
TEST_ASSERT_NOT_NULL(pipeline);
TEST_ASSERT_EQUAL(ESP_OK, audio_pipeline_register(pipeline, first_el, mid_el, last_el));
TEST_ASSERT_EQUAL(ESP_OK, audio_pipeline_link(pipeline, (const char *[]){"first", "mid", "last"}, 3));

Audio Peripheral¶

Example¶

esp_periph_config_t periph_cfg = {
    .event_handle = _periph_event_handle,
    .user_context = NULL,
};
esp_periph_init(&periph_cfg);

// Initialize button peripheral
periph_button_cfg_t btn_cfg = {
    .gpio_mask = GPIO_SEL_36 | GPIO_SEL_39
};
esp_periph_handle_t button_handle = periph_button_init(&btn_cfg);


esp_periph_start(button_handle);

ESP_LOGI(TAG, "wait for button Pressed or touched");

ESP_LOGI(TAG, "running...");
vTaskDelay(5000 / portTICK_RATE_MS);

esp_periph_stop(button_handle);
ESP_LOGI(TAG, "stop button...");
vTaskDelay(5000 / portTICK_RATE_MS);

esp_periph_start(button_handle);
ESP_LOGI(TAG, "start button...");
vTaskDelay(5000 / portTICK_RATE_MS);

ESP_LOGI(TAG, "destroy...");
esp_periph_destroy();

Audio Player¶

Example¶

esp_audio_cfg_t cfg = {
    .in_stream_buf_size = 4096,                    /*!< Input buffer size */
    .out_stream_buf_size = 4096,                   /*!< Output buffer size */
    .evt_que = NULL,                               /*!< Registered by uesr for receiving esp_audio event */
    .resample_rate = 48000,                        /*!< sample rate */
    .hal = NULL,                                   /*!<  */
};
audio_hal_codec_config_t audio_hal_codec_cfg =  AUDIO_HAL_ES8388_DEFAULT();
cfg.hal = audio_hal_init(&audio_hal_codec_cfg, 0);
esp_audio_handle_t player = esp_audio_create(&cfg);
TEST_ASSERT_NOT_EQUAL(player, NULL);
raw_stream_cfg_t raw_cfg = {
    .type = AUDIO_STREAM_READER,
};
audio_element_handle_t raw =  raw_stream_init(&raw_cfg);
wav_decoder_cfg_t wav_cfg = DEFAULT_WAV_DECODER_CONFIG();
audio_element_handle_t wav = wav_decoder_init(&wav_cfg);

 fatfs_stream_cfg_t fatfs_cfg = {
    .type = AUDIO_STREAM_READER,
    .root_path = "/sdcard",
};
i2s_stream_cfg_t i2s_cfg = I2S_STREAM_CFG_DEFAULT();
esp_audio_input_stream_add(player, fatfs_stream_init(&fatfs_cfg));

i2s_cfg.type = AUDIO_STREAM_WRITER;
esp_audio_output_stream_add(player, i2s_stream_init(&i2s_cfg));
wav_decoder_cfg_t wav_cfg = DEFAULT_WAV_DECODER_CONFIG();
esp_audio_codec_lib_add(player, AUDIO_CODEC_TYPE_DECODER, wav);

Development Boards¶

Hardware details of audio development boards designed by Espressif around ESP32.

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 ¶

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 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 LED: A general purpose LED controlled by the 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 V4.3 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 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 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 4 ohm speaker. The pins have a standard 2.54 mm / 0.1” pitch.
Right Speaker Output: Output socket to connect 4 ohm speaker. The pins have a standard 2.54 mm / 0.1” pitch.
PA Chip: A power amplifier used to amplify stereo audio signal from the Audio Codec Chip for driving two 4-ohm 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 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.
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 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

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 ¶

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	49,504
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	1,367
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	650
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¶

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.
Where to buy audio development boards produced by Espressif:
- ESP32-LyraT - Espressif Official Sample Provider, 乐鑫科技自营商城
- ESP32-LyraTD MSC - Espressif Official Sample Provider, 乐鑫科技自营商城

Copyrights and Licenses¶

Software Copyrights¶

Additional third party copyrighted code is included under the following licenses:

esp-stagefright is Copyright (c) 2005-2008, The Android Open Source Project, 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.

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

Audio Development Framework¶

Get Started¶

ESP32-LyraT V4.3 Getting Started Guide¶

What You Need¶

Overview¶

Components¶

Start Application Development¶

Initial Setup¶

Develop Applications¶

Summary of Key Changes from LyraT V4.2¶

Other Versions of LyraT¶

Related Documents¶

ESP32-LyraTD-MSC V2.2 Getting Started Guide¶

What You Need¶

Overview¶

Components¶

Start Application Development¶

Initial Setup¶

Develop Applications¶

Related Documents¶

About ESP-ADF¶

Setup ESP-IDF¶

Get ESP-ADF¶

Setup Path to ESP-ADF¶

Start a Project¶

Connect and Configure¶

Build, Flash and Monitor¶

Upload¶

Monitor¶

Update ESP-ADF¶

Related Documents¶

ESP32-LyraT V4.2 Getting Started Guide¶

What You Need¶

Overview¶

Functional Description¶

Hardware Setup Options¶

Allocation of ESP32 Pins¶

Start Application Development¶

Initial Setup¶

Develop Applications¶

Related Documents¶

ESP32-LyraT V4 Getting Started Guide¶

What You Need¶

Overview¶

Functional Description¶

Hardware Setup Options¶

Allocation of ESP32 Pins¶

Start Application Development¶

Initial Setup¶

Develop Applications¶

Related Documents¶

API Reference¶

Audio Framework¶

Audio Element¶

API Reference¶

Header File¶

Functions¶

Structures¶

Macros¶

Type Definitions¶

Enumerations¶

Audio Pipeline¶

API Reference¶

Header File¶

Functions¶

Structures¶

Macros¶

Type Definitions¶

Event Interface¶

Application Examples¶

API Reference¶

Header File¶

Functions¶

Structures¶

Macros¶

Type Definitions¶

Audio Common¶

API Reference¶

Header File¶

Macros¶