nanoFramework.Iot.Device.Es8156

ES8156 - Low-power stereo audio DAC (playback codec)

The Everest Semiconductor ES8156 is a low-power stereo audio DAC used on many ESP32 audio boards (ESP-BOX, ESP32-S3-Korvo, LyraT). It converts an I2S PCM stream into analog audio for a headphone/line output or a speaker amplifier.

This binding covers the I2C control plane only. It configures the codec (clocking, serial data format, volume, mute and power state). The actual PCM audio samples are streamed over I2S using System.Device.I2s and are not handled by this binding.

The register sequences are ported from the Espressif esp_codec_dev component and must be validated on real hardware. The default I2C address and the exact serial-format bit mapping depend on your board wiring - confirm against the schematic and codec datasheet.

Documentation

• ES8156 is configured over I2C (control) and streams audio over I2S (data).
• Two chips make up a full-duplex audio path on boards such as the ESP32-S3-BOX-Lite: the ES8156 (DAC, playback) and the ES7243E (ADC, capture).
• Espressif esp_codec_dev component - the source of the register sequences used by this binding (ES8156 driver source).
• Espressif ESP32-S3-BOX-Lite hardware overview and the ESP-BOX repository.

Audio path on the ESP32-S3-BOX-Lite

The I2C bus carries register configuration only (sample rate, data format, volume, mute, power). No audio samples travel over I2C. The actual PCM audio streams over I2S.

Usage

Important: I2C pins for the ESP32 must be properly set up before creating the I2cDevice. For this, make sure you install the nanoFramework.Hardware.Esp32 NuGet and use the Configuration class to configure the pins:

using Iot.Device.Es8156;
using nanoFramework.Hardware.Esp32;
using System.Device.Gpio;
using System.Device.I2c;
using System.Device.I2s;

// Setup ESP32-S3-BOX-Lite I2C control bus (SDA = GPIO8, SCL = GPIO18).
// GPIO8/GPIO18 are passed as pin numbers directly because the Gpio helper enum omits the
// classic ESP32 flash pins (IO6-IO11).
Configuration.SetPinFunction(8, DeviceFunction.I2C1_DATA);
Configuration.SetPinFunction(18, DeviceFunction.I2C1_CLOCK);

I2cConnectionSettings settings = new I2cConnectionSettings(1, Es8156.DefaultI2cAddress);
I2cDevice i2cDevice = new I2cDevice(settings);

Es8156 dac = new Es8156(i2cDevice);

// Enable the speaker power amplifier (POWER_AMP = GPIO46).
GpioController gpio = new GpioController();
GpioPin powerAmp = gpio.OpenPin(46, PinMode.Output);
powerAmp.Write(PinValue.High);

// Setup the ESP32 I2S transmitter first so MCLK/BCLK/WS are running before the codec is
// configured. ESP32-S3-BOX-Lite: BCLK = GPIO17, WS = GPIO47, DOUT = GPIO15, MCLK = GPIO2.
Configuration.SetPinFunction(17, DeviceFunction.I2S1_BCK);
Configuration.SetPinFunction(47, DeviceFunction.I2S1_WS);
Configuration.SetPinFunction(15, DeviceFunction.I2S1_DATA_OUT);
Configuration.SetPinFunction(2, DeviceFunction.I2S1_MCK);

I2sDevice i2s = new I2sDevice(new I2sConnectionSettings(1)
{
    Mode = I2sMode.Master | I2sMode.Tx,
    CommunicationFormat = I2sCommunicationFormat.I2S,
    ChannelFormat = I2sChannelFormat.RightLeft,
    BitsPerSample = I2sBitsPerSample.Bit16,
    SampleRate = 16_000,
    BufferSize = 40_000,
});

// A first write of silence starts the master clocks so the codec locks during configuration.
i2s.Write(new byte[512]);

// Bring the codec up and un-mute at a moderate volume.
dac.Initialize();
dac.Volume = 70;
dac.Muted = false;

// Write interleaved stereo 16-bit PCM to i2s.Write(...) to play audio. The sample generates
// a short triangle-wave melody so you can hear the DAC output on the speaker.

For other targets (STM32, etc.) use the preset hardware I2C pins (no SetPinFunction call needed).