mirror of
https://github.com/hathach/tinyusb.git
synced 2026-08-18 11:02:16 +00:00
4b1c8d16f7
Documentation tooling:
- Add the `build-doc` skill and `tools/build_doc.py` wrapper for local
Sphinx builds (clean / -W / open).
- Enable Markdown (MyST) in conf.py and auto-collect
examples/{device,host,dual}/*/README.md into a 3-level Examples nav
(Examples > Device/Host/Dual > example), noting each page's source
location and normalizing headings to a single H1.
- Remove the stale `.claude/commands/build-doc.md`; point the AGENTS.md
Documentation section at the skill.
Example docs:
- Add a README.md for every device/host/dual example: what it does, USB
interface table, notable tusb_config.h settings, generic CMake + Make
build steps, and how to try it.
- Fold each *_freertos variant into its base README, noting the FreeRTOS
source path and any RTOS-specific behavior.
Generated docs/examples/ output is git-ignored. Builds clean with
`sphinx-build -W`.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Audio Test Microphone
A minimal USB Audio Class 2.0 (UAC2) microphone that streams a generated test signal, useful for verifying the audio device stack end to end.
What it does
- Enumerates as a UAC2 microphone with 1 input channel at 48 kHz, 16-bit.
- An audio task fills a buffer with a continuously incrementing 16-bit ramp counter and writes it to the IN endpoint every 1 ms, simulating data from an I2S source. The counter resets when the streaming interface is closed.
- Handles UAC2 control requests: feature-unit mute/volume, clock-source sample-rate and clock-validity, and input-terminal connector.
- Blinks the on-board LED to indicate USB state (not mounted / mounted / suspended).
USB Descriptors
| Interface | Class driver |
|---|---|
| 0–1 | UAC2 audio (control + streaming), 1-channel microphone input |
Configuration
Notable tusb_config.h settings:
#define CFG_TUD_AUDIO 1
#define CFG_TUD_AUDIO_FUNC_1_SAMPLE_RATE 48000
#define CFG_TUD_AUDIO_ENABLE_EP_IN 1
#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX 1
#define CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX 2 // 16-bit
#define CFG_TUD_AUDIO_EP_SZ_IN TUD_AUDIO_EP_SIZE(TUD_OPT_HIGH_SPEED, CFG_TUD_AUDIO_FUNC_1_SAMPLE_RATE, CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_TX, CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX)
#define CFG_TUD_AUDIO_FUNC_1_EP_IN_SZ_MAX CFG_TUD_AUDIO_EP_SZ_IN
Building
CMake:
mkdir build && cd build
cmake -DBOARD=raspberry_pi_pico ..
cmake --build .
Make:
make BOARD=raspberry_pi_pico all
FreeRTOS variant
A FreeRTOS build is in examples/device/audio_test_freertos — identical single-channel UAC2 test microphone, with the device, audio, and LED-blink work split across FreeRTOS tasks.
Try it
The device appears as a single-channel USB microphone. On Linux, list it with arecord -l and capture with arecord (for example arecord -D hw:CARD=MicNode -c 1 -f S16_LE -r 48000 test.wav); the recorded samples form a rising ramp. The included src/plot_audio_samples.py records and plots the signal (requires sounddevice and matplotlib).