Buildroot dummy soundcard

I’ve setup a dummy soundcard for testing i2s3 on the 40 pin header for audio reliability. I’m happy to say that it is very reliable.
You can do your own build using this repo here :

Note that because of the following issue, booting is still manual :

Note that because of the following issue, device tree overlays don’t load and apply at boot time :

To make it work, do the following :

  • Add your rsa id public key to overlays/root/.ssh to get ssh login after booting
  • Build the buildroot system and write to sdcard.
  • At boot time, manually copy boot.cmd into uboot to get boot happening
  • Once logged in, prepare jackd for networked audio
    • Start jackd in net mode on your desktop/laptop
    • on the rock 3a, load up the bare audio soundcard :
    • on the rock 3a, run
    • on your desktop start a jackd enable audio software (such as jaaa)
    • on your desktop use qjackctl’s graph to connect the audio software to the system
  • on the rock 3a, use a shorting header to short the ADC and DAC pins and also the LRCLK_TX and LRCLK_RX pins

You are now piping audio through the dummy soundcard on the rock 3a back to your desktop computer.

1 Like