Hi Barry,

With the SanDisk MMC Cards there is a real pitfall which you
should be aware of:

- despite the fact that the statement in the manual says MMC
  cards can be used in MMC Mode OR in serial SPI Mode, SanDisk
  is actually shipping three types of cards:

  o Type1 can handle ONLY MMC Mode
  o Type2 can handle ONLY SPI Mode
  o Type3 can handle BOTH Modes!

- so you better double check with your suplier, wheter you have got
  the right card type (which i assujme is SPI for the PIC)

I had the same problem when using these cards in a 80C51 project.

Hope this is somewhat helpful

Reini OE3RDW

> -----UrsprŸngliche Nachricht-----
> Von: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]Im Auftrag von Barry King
> Gesendet am: Mittwoch, 03. November 1999 16:19
> An: PICLIST@MITVMA.MIT.EDU
> Betreff: Help with MultiMedia Cards
>
> I am working on interfacing a SanDisk MultiMedia Card flash to a
> PIC.
>
> So far, I am powering it up and sending what looks to me and my
> logic analyzer to be a correct command.  However, the MMC is not
> answering.
>
> Anyone out there have any experience with these MMCs?  I need a
> sanity check.  One of the things I'm not sure about is whether I've
> got the CRC right.  Anyone have working code?
>
> Thanks,
>
> Barry.
> ------------
> Barry King, KA1NLH
> Engineering Manager
> NRG Systems "Measuring the Wind's Energy"
> Hinesburg, Vermont, USA
> www.nrgsystems.com
>