Forum Discussion

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

Data stream to PCIe: regular or scatter gather DMA controller?

For a simple data flow (FIFO output to DMA controller to PCIe TXS port) is there any advantage to using the scatter/gather DMA controller rather than the regular DMA controller? There is only one ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

I've verified by interrogating the control registers with a NIOS and using a protocol analyzer that the 'DMA controller' IP does not work in a quartus/PCIe system. The transaction length register counts down to 0 and then ... keeps on going! packets never stop.

I've since discovered that chapter 1 'Introduction' to the Embedded Periperals IP User Guide says that this core is not 'supported by QSYS'. This is not mentioned in the chapter describing the DMA controller itself. This should be translated to mean: It doesn't work. I hope this post can prevent someone else from wasting time with this.