USBX Audio Class frame done callback not called

[nico23]

I've set up my STM32U5A9J-DK to use ThreadX and connect to my PC via USBX and Audio Class.

I'm correctly see the Audio Device on my PC and I can easily stream audio to it. The only thing is that, for some reason, the callback for new frame done is not fired

	audio_stream_parameter[0].ux_device_class_audio_stream_parameter_callbacks.ux_device_class_audio_stream_change
	= USBD_AUDIO_PlaybackStreamChange;

	audio_stream_parameter[0].ux_device_class_audio_stream_parameter_callbacks.ux_device_class_audio_stream_frame_done
	= USBD_AUDIO_PlaybackStreamFrameDone;

The strage thing is that USBD_AUDIO_PlaybackStreamChange is correctly called

VOID USBD_AUDIO_PlaybackStreamChange(UX_DEVICE_CLASS_AUDIO_STREAM *audio_play_stream,
                                     ULONG alternate_setting)
{
  /* USER CODE BEGIN USBD_AUDIO_PlaybackStreamChange */

  /* Do nothing if alternate setting is 0 (stream closed).  */
  if (alternate_setting == 0)
  {
    return;
  }

  BufferCtl.state = PLAY_BUFFER_OFFSET_UNKNOWN;

  /* Start reception (stream opened).  */
  ux_device_class_audio_reception_start(audio_play_stream);

  /* USER CODE END USBD_AUDIO_PlaybackStreamChange */

  return;
}

Instead, USBD_AUDIO_PlaybackStreamFrameDone is never called

VOID USBD_AUDIO_PlaybackStreamFrameDone(UX_DEVICE_CLASS_AUDIO_STREAM *audio_play_stream,
                                        ULONG length)
{
  /* USER CODE BEGIN USBD_AUDIO_PlaybackStreamFrameDone */

  UCHAR *frame_buffer;
  ULONG frame_length;

  /* Get access to first audio input frame.  */
  ux_device_class_audio_read_frame_get(audio_play_stream, &frame_buffer, &frame_length);

...
}

[T_Hamdi]

Hello @nico23 

To help you fix the issue where the ux_device_class_audio_stream_frame_done callback is not triggered, I recommend referring to the STM32WBA USBX Audio example available here:

STM32WBA BLE USBX Audio Example .

[FBL]

Hi @nico23 

Would you attach minimum firmware to reproduce the behavior? 

[nico23]

Hi @FBL 

Here you are https://github.com/NicoCaldo/NovaSonus_ThreadX

I'm seeing that my memory allocation is one-third the one in the example

#define USBX_DEVICE_MEMORY_STACK_SIZE       20 * 1024

vs

#define USBX_APP_MEM_POOL_SIZE       60 * 1024
#define USBX_MEMORY_STACK_SIZE       53 * 1024

Could it be the issue?

[FBL]

Hi @nico23 

I suggest isolate the USB audio functionality by disabling other middleware like TouchGFX to rule out conflicts and narrow down the issue. Would you please provide a minimal project based on this STM32U5A9J-DK board, without any other peripherals configured? This will help us assist you more efficiently.