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Setting the Last pNext in EPPI Chained Loopback

Question asked by spflanze on Oct 8, 2013
Latest reply on Oct 10, 2013 by CraigG

I am using VisualDSP++ for a VDK project on BF547. I am receiving DMA data across the EPPI interface from an AD7606 A to D converter. The buffer is setup for the Chained Loop back method.

 

My expectation was, since this is a loopback, that the pNext member of the last ADI_DEV_1D_BUFFER object in the chain should have a value that is the address of the first buffer of the chain. When I do this the function adi_dev_Read() returns error 0x40000013 which is "non-NULL terminated buffer list".

 

So, for chained loopback, should the last ADI_DEV_1D_BUFFER object's pNext member be set to NULL, and if set to NULL does the driver or Blackfin hardware know where the first ADI_DEV_1D_BUFFER object is in the chain to loop back to? Or is something else wrong?

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