#147427 - simonjhall - Thu Dec 20, 2007 2:43 pm
I need to transfer some data from slot-2 memory to main memory (in the order or tens of kb) and I happen to be on the ARM7 at the time.
Forgetting any IPC overhead etc etc, what's the difference in speed going to be if this DMA is started from the ARM7 or from the AMR9? Is the transfer speed determined by the relavent CPU clock or the bus clock? Or is there in fact no difference between the two, eg the DMA controller lives on the bus?
Anyone have any experience with doing this sort of thing before?
EDIT: just a tip for people who are wondering why their data ain't coming back right - DMA on ARM7 can't handle the same address and sizes ranges as ARM9 DMA. Just wasted an hour finding that out ;-)
_________________
Big thanks to everyone who donated for Quake2
Forgetting any IPC overhead etc etc, what's the difference in speed going to be if this DMA is started from the ARM7 or from the AMR9? Is the transfer speed determined by the relavent CPU clock or the bus clock? Or is there in fact no difference between the two, eg the DMA controller lives on the bus?
Anyone have any experience with doing this sort of thing before?
EDIT: just a tip for people who are wondering why their data ain't coming back right - DMA on ARM7 can't handle the same address and sizes ranges as ARM9 DMA. Just wasted an hour finding that out ;-)
_________________
Big thanks to everyone who donated for Quake2