Hi,
I'm trying to configure a eZdsp_F28335 McBSP to read from a buffer via DMA and via loopback store the results in another DMA buffer and repeat the cycle indefinitely without using an external to the DMA or McBSP interrupt to set the DMA RUN bit for each transfer. Is this possible? I would like to use the sample rate generator to produce frame-synchronization pulses (FSXM = 1 and FSGM = 1) and have the transmissions synchronised with them sending the same set of values repeatedly.
I have a basic transfer set up where I drive the transmission via a timer interrupt that sets the RUN bit in the source and destination DMA and via the McBSP the results appear in the destination DMA buffer. This configuration works great, however I would like to remove the timer interrupt and enable FSXM and FSGM and have the transfers complete indefinitely without having a remote timer interrupt driving the transfer. Is this possible?
I have made several attempts to configure this repeating transfer arrangement, but I seem to only produce random values in the destination DMA buffer. I zero the destination buffer out and then set the source and destination DMA RUN bits to 1 along with setting FSXM and FSGM. I've also played with the SRC_WRAP_SIZE in an attempt to set the src pointer back to the beginningwhen it reaches the end of the buffer, but this did not seem to help. Basically I want to keep the DMA RUN bits set and have the McBSP transfer data on each cycle.
I've been through all the examples I could find and have yet to see one with this capability set up, so I'm not sure it possible, but I do see a need for it.
Thanks for your help!