M5Stack CoreS3 has dual MEMS microphones connected via ES7210 4-channel ADC. This PR implements ES7210 initialization and I2S configuration based on M5Unified to enable embedded:io/audio/in.

Changes

New ES7210 driver (modules/drivers/peripherals/es7210/)

• I2C initialization sequence at 0x40 matching M5Unified register configuration
• Microphone gain, bias, and filter setup
• Error handling for missing hardware

M5Stack CoreS3 target updates

• manifest.json: Add audioin module, configure I2S_NUM_1 stereo @ 16kHz, pins BCK=34/WS=33/DATAIN=14
• setup-target.js: Initialize ES7210 during target setup

audioin.c enhancement

• Support stereo I2S mode when numChannels=2 (was hardcoded to mono)
• Use MODDEF_AUDIOIN_I2S_SLOT define for slot mask configuration

Implementation Notes

• Speaker and mic share I2S bus (different data pins: 13/14)
• Standard I2S mode, not PDM
• Stereo captures both onboard microphones

Usage

import AudioIn from "embedded:io/audio/in";

const input = new AudioIn({
    onReadable(size) {
        const samples = new Int16Array(size / 2);
        this.read(samples.buffer);
        // Stereo samples: [L0, R0, L1, R1, ...]
    }
});
input.start();

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.