nanoFramework.Iot.Device.Aw88298 1.0.7

AW88298 - I2S Class-D smart audio amplifier (speaker output)

The Awinic AW88298 is a 16-bit I2S Class-D smart audio amplifier with an integrated boost converter and DSP. It drives a speaker directly from an I2S PCM stream and is used, for example, on the M5Stack CoreS3 to drive the built-in 1W speaker.

This binding covers the I2C control plane only. It configures the amplifier (reset, power/enable, output volume, mute and boost). The PCM audio samples are streamed over I2S using System.Device.I2s and are not handled by this binding.

Documentation

• AW88298 is configured over I2C (control) and streams audio over I2S (data).
• On the M5Stack CoreS3 the AW88298 (speaker) and the ES7210 (microphones) share the same internal I2C bus and I2S data lines.
• Espressif esp_codec_dev component - the source of the register sequences (AW88298 driver source).
• M5Stack CoreS3 documentation and the Espressif CoreS3 board support package.

Audio path on the M5Stack CoreS3

Usage

using Iot.Device.Aw88298;
using nanoFramework.Hardware.Esp32;
using System.Device.I2c;
using System.Device.I2s;

// Setup the M5Stack CoreS3 internal I2C bus (SDA = GPIO12, SCL = GPIO11).
Configuration.SetPinFunction(12, DeviceFunction.I2C1_DATA);
Configuration.SetPinFunction(11, DeviceFunction.I2C1_CLOCK);

I2cConnectionSettings settings = new I2cConnectionSettings(1, Aw88298.DefaultI2cAddress);
I2cDevice i2cDevice = new I2cDevice(settings);

Aw88298 amplifier = new Aw88298(i2cDevice);

// Setup the ESP32 I2S transmitter (MCLK = GPIO0, BCLK = GPIO34, WS = GPIO33, DOUT = GPIO13).
Configuration.SetPinFunction(34, DeviceFunction.I2S1_BCK);
Configuration.SetPinFunction(33, DeviceFunction.I2S1_WS);
Configuration.SetPinFunction(13, DeviceFunction.I2S1_DATA_OUT);
Configuration.SetPinFunction(0, 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,
});

// Start the clocks, then configure the amplifier.
// Initialize takes the I2S sample rate so the amplifier's I2S control register matches the stream.
i2s.Write(new byte[512]);
amplifier.Initialize(16_000);
amplifier.Volume = 100;
amplifier.Muted = false;
amplifier.Start();

// Write interleaved stereo 16-bit PCM to i2s.Write(...) to play audio.