4-bit SD Card mode

[Neil Bradley]

>> What is the CPU in question?
> There are issues with AT91RM9200, but now I think the problem is something
> else than I assumed.

One possibility - If DMA mode is being used, has there been a cache flush 
on the region of memory where the SD card reads into? The ARM7/9 is *NOT* 
cache coherent with DMA peripherals, which can give all kinds of bizarre 
problems if the destination buffers are in the system's cache.

-->Neil

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C. Neil Bradley - KE7IXP - The one eyed man in the land of the blind is not
                            king. He's a prisoner.