I modified the EDMA video port DMA driver to read the video port status upon completion of video frame capture.The chaining etc all work OK, but I always get back 0. I know there is non-0 there, processor can read this location fine. I tried other video port registers - still 0. I change the address so upon completion DMA instead reads from location in ext RAM with known value, and it works OK.
It seems that the EDMA can not read certain internal dm648 registers. I can not find in any datasheet where EDMA may have limited access to the dm648 memory map.
Is there a limitation? Is there something I have set wrong? Could it be the privilege level?