reSpeaker XVF3800 USB Audio Bridge with XIAO ESP32S3

Overview

This project provides Arduino firmware for an ESP32-S3 USB audio and control bridge connected to a reSpeaker XVF3800. A single native USB connection provides stereo capture, stereo playback, and a CDC serial interface for reSpeaker XVF3800 control over I2C.

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Firmware Features

• USB Audio Class 1 (UAC1) capture and playback over Full-Speed USB.
• Stereo signed 32-bit little-endian PCM, with 32-bit Philips I2S slots.
• Compile-time selection of 16 kHz or 48 kHz operation and the I2S clock source.
• Simultaneous USB capture and playback. USB and I2S use the same nominal sample rate.
• Playback buffering and software clock drift correction, with USB host volume and mute controls for the master and individual channels.
• Capture without playback volume processing or software resampling.
• USB CDC commands forwarded to the reSpeaker XVF3800 I2C control interface, with a Python host utility and read-only audio/USB diagnostics.
• A project-local TinyUSB DWC2 driver and USB descriptors that fit duplex audio and CDC into the ESP32-S3 hardware FIFO budget.

Audio Modes

Set BRIDGE_MODE in bridge_config.h, then rebuild the complete sketch. Master and Slave in the macro names describe the reSpeaker XVF3800 role. The ESP32-S3 uses the opposite role.

Mode	Sample rate	reSpeaker role	ESP32-S3 role	Clock source
BRIDGE_I2S_MASTER_48K	48 kHz	Master	Slave	reSpeaker
BRIDGE_I2S_MASTER_16K	16 kHz	Master	Slave	reSpeaker
BRIDGE_I2S_SLAVE_16K	16 kHz	Slave	Master	ESP32-S3

The reSpeaker XVF3800 must run firmware configured for the matching sample rate and I2S role. The bridge does not configure or flash the reSpeaker. Mode selection requires recompilation; there is no runtime rate switch or 16/48 kHz conversion.

Requirements

• An ESP32-S3 board with native USB; the supplied profile targets the Seeed Studio XIAO ESP32S3.
• Arduino IDE or Arduino CLI with the Espressif board package available.
• Arduino-ESP32 3.3.11.

No separate USB audio library is required. Use the pinned core version: the local USB driver override and descriptors depend on its TinyUSB implementation.

Build Settings (Arduino IDE)

Open reSpeaker_ESP32S3_USB_BRIDGE.ino, install/select Arduino-ESP32 3.3.11, and use these settings:

Setting	Value
Board	Seeed Studio XIAO_ESP32S3
USB Mode	USB-OTG (TinyUSB)
USB CDC On Boot	Disabled
Upload Mode	USB-OTG CDC (TinyUSB)
USB Firmware MSC On Boot	Disabled
USB DFU On Boot	Disabled
CPU Frequency	240 MHz
PSRAM	Disabled

In short: USB Mode = USB-OTG (TinyUSB); CDC/MSC/DFU On Boot = Disabled; CPU = 240 MHz; PSRAM = Disabled.

The firmware creates its own CDC interface, so CDC On Boot must remain disabled. In the pinned CLI profile, CDCOnBoot=cdc corresponds to Disabled. The sketch checks these three USB settings at compile time. Upload Mode is checked through ARDUINO_FQBN, because the core does not define a separate upload-mode macro. The CLI profile explicitly selects UploadMode=cdc to request the 1200-baud reset and wait for the download port.

Select Verify to compile, then Upload.

Download and Install

1. Download the firmware from GitHub: reSpeaker_ESP32S3_USB_BRIDGE.
2. Copy the entire contents of the downloaded repository into a new folder Documents\Arduino\reSpeaker_ESP32S3_USB_BRIDGE. Include all files: the .ino, headers, .cpp files, sketch.yaml, host\, src\, and docs. Copying only the .ino file is insufficient.
3. Edit bridge_config.h in the new folder to select the 16 kHz mode, If you are using:

// #define BRIDGE_MODE BRIDGE_I2S_MASTER_48K
#define BRIDGE_MODE BRIDGE_I2S_SLAVE_16K

4. In Arduino IDE, open File > Sketchbook > reSpeaker_ESP32S3_USB_BRIDGE (the folder name now matches the .ino).

Check USB Enumeration

Disconnect and reconnect the USB cable. You should see:

• A CDC serial port (for example, COM5 on Windows) — this is the control port.
• An audio device named BRIDGE I2S Slave 16k (stereo, 32-bit, 16 kHz in and out).

Close any program (such as a serial monitor) that is holding the port before continuing.

Verify the Control Side (Host Tool)

From the repository, enter the host folder and install the dependency:

cd host
python -m venv .venv
.venv\Scripts\activate.bat
python -m pip install -r requirements.txt
python bridge_host.py --list-ports
python bridge_host.py --port COMx --ping
python bridge_host.py --port COMx VERSION

Replace x in COMx with your actual COM port number. On Linux or macOS, activate the virtual environment with source .venv/bin/activate and use a path such as /dev/ttyACM0 or /dev/cu.usbmodemXXXX instead of COMx.

Expected Results

Test Audio

• Playback: play a stereo 32-bit 16 kHz WAV file to the BRIDGE I2S Slave 16k output; sound should come from the reSpeaker codec/speaker.
• Capture: record 16 kHz stereo 32-bit audio from its input.

Reference Audacity Snapshot

Resources

• reSpeaker_ESP32S3_USB_BRIDGE firmware (GitHub)
• README.md — firmware overview, audio modes, and build instructions.
• PLAYBACK.md — audio wiring, playback buffering, diagnostics, and audio/USB status.
• CONTROL.md — I2C wiring, the Python host utility, and the CDC serial protocol.

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