STM32 uac2_headset example SAI DMA data corruption

[pm-daniel]

PC OS : Windows 10 Pro 2004 Board : NUCLEO-H743ZI2 Firmware: examples/device/uac2_headset

I'm having trouble using SAI in DMA mode to transmit received audio samples to external codec ic. It looks like half of the data is being somehow corrupted (for each ~1ms SAI transmission of correct data, there is ~1ms of silence). I'm attaching code snippets:

bool tud_audio_rx_done_cb callback when SAI transmission is being set up (DMA is not using circular buffer): bool tud_audio_rx_done_cb(uint8_t rhport, uint8_t *buffer, uint16_t buf_size) { (void)rhport; rx_buff = buffer; HAL_SAI_Transmit_DMA(&hsai_BlockA1, (uint8_t *)rx_buff, 192); return true; }

SAI config parameters: hsai_BlockA1.Instance = SAI1_Block_A; hsai_BlockA1.Init.AudioMode = SAI_MODEMASTER_TX; hsai_BlockA1.Init.Synchro = SAI_ASYNCHRONOUS; hsai_BlockA1.Init.OutputDrive = SAI_OUTPUTDRIVE_DISABLE; hsai_BlockA1.Init.NoDivider = SAI_MASTERDIVIDER_ENABLE; hsai_BlockA1.Init.FIFOThreshold = SAI_FIFOTHRESHOLD_EMPTY; hsai_BlockA1.Init.AudioFrequency = SAI_AUDIO_FREQUENCY_48K; hsai_BlockA1.Init.SynchroExt = SAI_SYNCEXT_DISABLE; hsai_BlockA1.Init.MonoStereoMode = SAI_STEREOMODE; hsai_BlockA1.Init.CompandingMode = SAI_NOCOMPANDING; hsai_BlockA1.Init.TriState = SAI_OUTPUT_NOTRELEASED;

Maybe someone will be able to tell whether I'm doing something wrong or it's a bug?

Log: https://pastebin.com/Z0Qv7Mwf

[pm-daniel]

Apparently, the problem was caused by USB-SAI timing issues, not by the USB stack itself.