Suppose that DMA is programmed to transfer 4 samples (4 bytes each) to SAI0 TX in one minor loop. There are two minor loops per major loop. SAI TX triggers the DMA transfer through request.
If watermark for SAI TX FIFO is set to 1 what will be the DMA transfer behavior:
opt. 1: SAI triggers request when FIFO level is less or equal 1, DMA performs 1 minor loop (transfers 4 samples), then DMA waits for next request from SAI (when FIFO level is again less or equal 1) to transfer the second minor loop
opt. 2: SAI triggers request when FIFO level is less or equal 1, DMA performs 1 minor loop (transfers 4 samples), then DMA peforms the second minor loop, not waiting for next request from SAI
Also a question: how does SAI<->DMA request handshaking work?