How does a DMA synchronize to the first element of the McBSP? The McBSP will
send events to the DMA on every element transfer, but how does the DMA
synchronize to an EXTERNAL frame synch (and clock)?
Should the McBSP frame interrupt be used to start the McBSP
transmitter/reciever? Presently the DMA is started and subsequently the McBSP.
The McBSP is started irrespective of the external frame pulse.
I am testing a loopback using a pair of DMAs and a McBSP (internal loopback in
the McBSP), and notice the elements are shifted in reception. The TX side is
verified against a scope and it is fine. (the McBSP uses a 1-bit delay in both
TX and RX)
Furhtermore, I even observe one TX transfer to be slip as well when two McBSPs
are used (I'm actually using 2 McBSP, 4 DMA, and 4 ping-pong buffer pairs.
The DMA transposes 32 elements by 32 frames).
I tested this on an EVM and it works to no surprise, but obviously I had to used
the internal sample rate generator a synchronization source.
