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Altera_Forum
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16 years ago

memory-to-memory sgdma problem

Hello, I am testing the sgdma core by copy data from one on-chip-memory buffer to the other. However, I met a confusing problem that the actual_transfered_bytes is always zero. Can anybody he...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

The length of your buffer is 40 (10 words of 4 bytes each). Like others have said make sure the data isn't held in the cache.

I can't remember if actual bytes transferred is supposed to update for MM->MM transaction types since there is no need to know it (you tell the DMA how much data to move). The actual bytes transferred field is meant for ST-->MM transactions with packet support enabled since you will not know how much data is arriving.