I've read through the datasheet multiple times and concluded that the case is impossible, but decided to ask smarter people here.
I'm reading ADC data to memory1 with DMAC. It works.
I'm writing from memory2 to I2S with DMAC. It works.
Doing these two simultaneously doesn't.
I'm reading two ADC channels to alternating buffers. Do some audio processing (in an Arduino loop) and write to another alternating buffer. The later is sent to I2S to an Audio Driver. I tried doing it with DMAC but it would only do one of these at a time. Read a whole buffer or write a whole buffer. I switched to reading ADC wit DMAC, and writing I2S with interrupts. (obviously there is a delay of a few tens of ms between the input signal and output signal in my case, which is perfectly fine, and not part of the problem)
Any way to make it all work (like magic) with DMAC?