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ATAPI-4 mode for CompactFlash

Started by Martin March 30, 2004
I want ask which mode is using CompactFlash device. It's not clear
from ATAPI-4 spec. Is it always PIO in/out protocol or can I even run
write/read in any of DMA modes?
Martin wrote:

> I want ask which mode is using CompactFlash device. It's not clear > from ATAPI-4 spec. Is it always PIO in/out protocol or can I even run > write/read in any of DMA modes?
Have a look at http://www.sandisk.com/pdf/industrial/ProdManualIndustrialGradeATAv2.6.pdf http://www.sandisk.com/pdf/industrial/ProductManualStdGradev1.5.pdf They support PIO0..4 and DMA0..2. Tankred.
Martin wrote:
> I want ask which mode is using CompactFlash device. It's not clear > from ATAPI-4 spec. Is it always PIO in/out protocol or can I even run > write/read in any of DMA modes?
1) DMA DMA is only supported in true IDE mode; not removable CompactFlash/PCMCIA mode. Of course, you can power-up a CompactFlash device in true IDE mode... if you want. 2) PIO Someone please correct me if I'm wrong, but there seems to be a bit of a problem with CompactFlash and PIO; firstly, PIO is really only appropriate for x86/PC-AT (or architecures where IO and memory are in different address spaces). If you want to use CompactFlash in memory-mapped mode (as most embedded products do), then PIO timings are not much help; there don't seem to be any equivalent 'Memory Cycle' timings in the device identity or CIS. Regards Tim