1 Reply Latest reply on Sep 12, 2011 6:04 AM by anand.srinivasan.asokan

    Who own the memory when calling CyU3PDmaChannelSetupSendBuffer?

    oliver.king-smith

      If I receive a DMA buffer from the GPIF (that is I get a callback) can I use the DMA buffer by passing it to CyU3PDmaChannelSetupSendBuffer?

         

      Can I create a "fake" CyU3PDmaBuffer_t where the buffer field points at a location in memory that another DMA channel is using?

         

      For example can I call CyU3PDmaChannelGetBuffer to get a CyU3PDmaBuffer_t for a DMA transfer that just completed, and then pass that to CyU3PDmaChannelSetupSendBuffer to commit the same buffer with no memory copying to the outgoing DMA channel?

         

      Likewise can I allocate my own CyU3PDmaBuffer_t by using a CyU3PMemAlloc and then populate the fields to make it looks like a CyU3PDmaBuffer_t?

         

      CyU3PDmaBuffer_t *my_dma = (CyU3PDmaBuffer_t *)CyU3PMemAlloc(sizeof(CyU3PMemAlloc));

         

      my_dma.buffer = p; /* some location in memory that is part of a dma memory on another channel */

         

      my_dma.count = 1;

         

      my_dma.size = length_to_transfer; /* amount of memory to transfer */

         

      my_dma.status = ???; /* not sure what should go here, maybe CyU3PDmaMode_t */