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Altera_Forum
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17 years ago

How to define the NULL descriptor in SGDMA

I use the SGDMA in TSE MAC. As its document said, the last descriptor in the descriptor chain must be a NULL descriptor. But I wonder how to define the NULL descriptor. I define it in followin...
Altera_Forum's avatar
Altera_Forum
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17 years ago

Correction:

- the null descriptor is the last descriptor with the OWNED_BY_HARDWARE bit _cleared_. (not set as I typed earlier).

Addition:

- the null descriptor addresses and length are "don't cares", as the SG DMA engine will not perform a DMA transfer for this last descriptor.

Can someone comment if this is correct or not??