Lpc2000

On Sat, Feb 07, 2004 at 03:27:23AM -0500, J.C. Wren wrote:
> The SD/MMC card connector will support the physical SD card.  I had 
> planned on only supporting the SPI mode, but there's several uncommitted 
> I/O lines on the processor, so I may wire those up (with jumpers, of 
> course) to support SD mode.

Some comments to SD and MMC cards. In SPI mode all commands from the SD mode
are also available. One-Wire SD mode has the same speed as the SPI mode.
(3.125MBit/s burst rate at 25Mz clock). You can speed up this to 12MBit/s by
using the 4 data lines in 4bit SD mode, but I guess this can not be done by
using simple IO-Pins, or timer inputs/outputs (much too slow).  With no
additional hardware the SPI-mode of the SD card is the best solution for the
lpc21xx. And I doubt that you can use it at the full speed. (What is the
max. frequency of the lpc21xx SPI?).

        Matthias