audio_4_channel_mic on STM32F411 with modified tud_audio_tx_done_post_load_cb

[klaus-liebler]

Operating System

Windows 11

Board

BlackPill F411

Firmware

audio_4_channel_mic example (unmodified and modified, see below)

What happened ?

I successfully integrated the audio_4_channel_mic example in a new STM32CubeIDE project and used "plot_audio_samples.py" to test it. When I looked at the plot, I saw that the value 1 remains constant for two samples (see marking in the screenshot below). According to the source code, the value 1 should only be displayed for one sample.

I investigated further and changed the "Generate dummy data" code to get unique sample values on all four channels

for(int i=0;i<48;i++){
  i2s_dummy_buffer[0][2*i]   = 100+i;
  i2s_dummy_buffer[0][2*i+1] = 200+i;
  i2s_dummy_buffer[1][2*i]   = 300+i;
  i2s_dummy_buffer[1][2*i+1] = 400+i;
}

Again I started "plot_audio_samples.py".

Expected result: A sawtooth with continuously increasing values from 400->447

Actual result: A sawtooth with the values 400->446 and then a drop to 100 (47 of 48 values of second fifo, second channel, then the first value oder first fifo and first channel).

How to reproduce ?

Compile and run example here https://github.com/klaus-liebler/soundcard

Debug Log as txt file (LOG/CFG_TUSB_DEBUG=2)

Not available

Screenshots

See above

I have checked existing issues, dicussion and documentation

• I confirm I have checked existing issues, dicussion and documentation.

[HiFiPhile]

Could you try #2259 ?

After fix:

[klaus-liebler]

Thank you so much, @HiFiPhile . I can confirm, that #2259 fixes the problem.

Regards, Klaus