Audio Codec Driver Guide

A codec driver in TuyaOpen connects an audio codec IC to the tdl_audio_* application interface, so an app can play and capture PCM without touching the I2S or I2C buses directly. This guide integrates a codec for voice interaction, audio playback, and AI applications.

Prerequisites

• Read TDD/TDL Driver Architecture
• Board with I2S and I2C interfaces
• Audio codec datasheet (e.g., ES8311, ES8388, ES8389)

Audio Architecture

TDL Audio Interface

The application interacts through tdl_audio_*:

tdl_audio_find("audio_device", &handle);
tdl_audio_open(handle, &audio_cfg);
tdl_audio_play(handle, pcm_data, len);
tdl_audio_close(handle);

Platform Differences

Aspect	T5AI	ESP32-S3
TDD location	src/peripherals/audio_codecs/tdd_audio/	boards/ESP32/common/audio/
I2S driver	TKL tkl_i2s_*	ESP-IDF i2s_channel_*
I2C control	TKL tkl_i2c_*	ESP-IDF i2c_master_*
Codec library	Internal	esp_codec_dev (ESP-IDF component)
Supported codecs	Platform audio IC	ES8311, ES8388, ES8389, no-codec (DAC)

ESP32 Audio Codec Registration Flow

Using ES8311 as example (from boards/ESP32/common/audio/tdd_audio_8311_codec.c):

1. Configure the codec

TDD_AUDIO_8311_CODEC_T codec_cfg = {
    .i2c_cfg = {
        .i2c_scl_io = I2C_SCL_IO,
        .i2c_sda_io = I2C_SDA_IO,
        .i2c_port = 0,
        .i2c_addr = 0x18,
    },
    .i2s_cfg = {
        .i2s_mclk_io = I2S_MCK_IO,
        .i2s_bclk_io = I2S_BCK_IO,
        .i2s_ws_io = I2S_WS_IO,
        .i2s_dout_io = I2S_DO_IO,
        .i2s_din_io = I2S_DI_IO,
    },
    .sample_rate = 16000,
    .pa_gpio = GPIO_OUTPUT_PA,
};

2. Register in board init

void board_register_hardware(void)
{
    tdd_audio_8311_codec_register("audio", codec_cfg);
}

3. TDD internally

• Creates I2C master bus via ESP-IDF
• Creates I2S duplex channel via ESP-IDF
• Initializes ES8311 via esp_codec_dev
• Fills TDD_AUDIO_INTFS_T (open, play, config, close)
• Calls tdl_audio_driver_register("audio", handle, &intfs, &info)

Available ESP32 Audio Codecs

Codec	File	I2C Addr	Notes
ES8311	tdd_audio_8311_codec.c	0x18	Common on S3 boards
ES8388	tdd_audio_es8388_codec.c	0x20	Alternate codec
ES8389	tdd_audio_es8389_codec.c	Varies	DNESP32S3-BOX2
No codec	tdd_audio_no_codec.c	N/A	Direct DAC output
ATK no codec	tdd_audio_atk_no_codec.c	N/A	Alternate no-codec

Writing a New Codec TDD

To add support for a new codec (e.g., WM8960):

1. Create tdd_audio_wm8960.c and tdd_audio_wm8960.h
2. Implement the four interface functions: open, play, config, close
3. In open: init I2C, init I2S, configure codec registers
4. In play: write PCM data to I2S channel
5. In config: handle sample rate changes, volume, mute
6. In close: stop I2S, power down codec
7. Call tdl_audio_driver_register() at the end of your register function

References

• TDD/TDL Driver Architecture
• Audio Driver Reference
• ESP32 Supported Features