> 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?
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.
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.