Digital audio input/output between 2 or more Belas

resynth

Hi,

Looks like I need to use 2 Bela's connected in series for a project. It's a processing power thing but the processing can be split into 2 distinct stages in series.

Is it possible, for sound quality and latency reasons, to skip out the DAC & ADC and send digital audio direct from one Bela to the other?

Thanks

giuliomoro

That's interesting and it could be done, but there is need to make some changes that are not necessarily trivial. On the hardware side, you have to connect the output data line of one to the input data line of the other one and the bitclock and frame sync of the second one also need to come from the bitclock out and frame sync out of the first one. The codec on the first one has to be set to I2sMain mode and the second one then has to be set to I2sSecondary mode. This should be doable with a decently shielded wire and a few flags in software. The other thing you need to do is to tell the second device's codec not to generate any data on the Bela input side. This requires a bit of datasheet digging to figure out what codec settings need to be changed. With a bit more effort on the software side you could get away with not using a cape at all on the second board and only use it as an "effect insert" while using ADC and DAC all on the first board.