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MMC command definitions?

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Rob Turk

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Mar 10, 2003, 5:24:01 AM3/10/03
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Hello group,

Anyone here have a good reference to the protocol for SPI communication with
MultiMedia Card (MMC) memory devices? How do I read/write blocks and how do
I get status? Sample code would be nice ;-)

Thanks,
Rob


Stef

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Mar 10, 2003, 5:42:39 AM3/10/03
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I will not call them good reference, but there is a lot of info in the
hitachi datasheets and user manuals.

Make sure you clock in a few extra 0xFF's before and after the commands
and data. Or use an SPI bus with a continously running clock and
high-state data line when idle.

Remember that if you are reading data, you will have to keep the clock
running, even if you are just waiting for the device to start it's
answer. When using the AT91 SPI module, this means you will have to keep
sending 0xFF continously when waiting for a reply.

Stef


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