uac2_headset example with stereo microphone

[klusekb]

Hi,

I added TinyUSB and the UAC2 headset example to a STM32CubeMX project (STM32F411 MPU). It worked fine - everything I sent to the speaker came back from the microphone. Yay!

But, what I really need is a device with a two input channels. I tried the following:

In tusb_config.h, I changed

#define CFG_TUD_AUDIO_FUNC_1_N_CHANNELS_TX 2

In main.c, audio_task(), I adjusted the "limit" and amount of data to be written (as the microphone is stereo now):

  int16_t *src = (int16_t*)spk_buf;
  int16_t *limit = (int16_t*)spk_buf + spk_data_size / 1;
  int16_t *dst = (int16_t*)mic_buf;
  while (src < limit)
  {
    // Combine two channels into one
    int32_t left = *src++;
    *dst++ = left;
    int32_t right = *src++;
    *dst++ = right;
    //*dst++ = (left >> 1) + (right >> 1);
  }
  tud_audio_write((uint8_t *)mic_buf, spk_data_size / 1);
  spk_data_size = 0;

This compiles and runs, and is recognized as a TinyUSB headset microphone and headphones. Also, the audio_task code above runs whenever I output any sound. Sadly, nothing makes it back through the microphone path.
One thing that seemed suspect to me was _nchannelslogical hardcoded as 0x01 in usb_descriptor.h, line 103:

TUD_AUDIO_DESC_INPUT_TERM(/_termid/ UAC2_ENTITY_MIC_INPUT_TERMINAL, /_termtype/ AUDIO_TERM_TYPE_IN_GENERIC_MIC, /_assocTerm/ 0x00, /_clkid/ UAC2_ENTITY_CLOCK, /_nchannelslogical/ 0x01, /_channelcfg/ AUDIO_CHANNEL_CONFIG_NON_PREDEFINED, /_idxchannelnames/ 0x00, /_ctrl/ 0 * (AUDIO_CTRL_R << AUDIO_IN_TERM_CTRL_CONNECTOR_POS), /_stridx/ 0x00),\

But, nothing happens when I change it to 2.

Any ideas? Am I doing something completely wrong?

Thanks!
Bart

[hathach]

do you see any complains from PC kernel/driver log, also please double check with UAC2 specs to make sure you don't miss any other descriptors fields.