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Altera_Forum's avatar
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
Icon for Honored Contributor rankHonored Contributor
17 years ago

I also had this question, and I am not sure what is the correct answer.

I *think* that a null descriptor is the (last) descriptor with the OWNED_BY_HARDWARE bit set. It's addresses and length are "don't cares".

I think the SG DMA engine will stop upon reaching this descriptor.

The documentation is not quite clear on this.

Regards,

Leon.