A handheld gadget under development has a problem reading certain
types of 32 Meg SD cards.  It works with RiData and Sandisk, but
doesn't work with Lexar, Panasonic, etc.
I'm looking for detailed specs on the cards, the protocol, or anything
that would lead to an answer of why this could be.

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Clarification of Question by bigman2000-ga on 28 Aug 2003 10:08 PDT

Cards were all formated by the same win2k box.  Problem appears even
when FAT file system is not used and the physical device is accessed
by sector.

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Request for Question Clarification by arimathea-ga on 28 Aug 2003 13:13 PDT

bigman2000-ga,

Thanks for your response.  I've found some specifications on the
standards themselves for your review, but I suspect you already have
them.    They are:

http://www.mmca.org/tech/MMC-System-Summary-v3.31.pdf 
http://www.sdcard.org/sdphysical_simplifyed_Ver101.PDF
http://www.sdcard.org/SDIO-SimpleSpec-1.00_A.pdf
http://www.sdcard.org/Simple_of_SDIO_Card_Type-A_Spec_v1.0_Draft_C_20020524.pdf

The complete specifications for the systems themselves cost a
significant amount of money, so i'm not able to provide them.  I
haven't yet been able to locate any specifications on the cards
themselves.  One source noted that the Lexar card (and probably the
other cards you're having problems with) apparently have a USB core in
silicon on the card itself, which may be leading to the
incompatibility.  It may also be worthwhile to check out Storage
Tools:

   http://www.softwinter.com/storagetools.html

A number of individuals seem to report success using these cards after
working with Storage Tools.  It's a commercial product, though, and I
cannot speak directly to its effectiveness.

I'm still researching.  Thanks for your patience.

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Clarification of Question by bigman2000-ga on 28 Aug 2003 14:59 PDT

Thanks, those may be helpful, not sure yet.   Am aware of sites like 
 http://www.xtdnet.nl/paul/toshiba_m1283bx.pdf
but it doesn't say much about what the sdcard is supposed to answer with.

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Request for Question Clarification by arimathea-ga on 09 Sep 2003 21:27 PDT

bigman2000-ga,

Did you have any luck with the specifications I located?  It seems as
if at least the SDIO Simple Specification talks protocol details.  If
my specifications were of assistance, i'll be happy to post them as an
answer and close this question out.

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Clarification of Question by bigman2000-ga on 09 Sep 2003 22:32 PDT

The bit loss or shifting problem is exhibited even when the first
sector on the card is read repeatably.  So it is not a formatting or
fragmentation issue.  It looks like a clock timing problem, but the
clock is clean.

The SDCARD.org specs are designed to be bad enough to get you to pay
$1500 to get the real specs.  They don't have necessary details.

bigman2000-ga,

I'm still searching for your specifications, but i'd like to recommend
that you try to reformat the cards that are having difficulties. 
There isn't any direct information I could find leading to a
specification difference between Sandisk/Lexar/Panasonic/RiData, but I
did find a host of documents referring to incompatibilities due to
format differences.

If this ends up answering your question, let me know and I will post
it as an answer.

Thanks!
arimathea-ga

SanDisk has product manuals on their site.  These manuals do have
detailed timing info and command reference.  I'd get these instead of
paying $500 to mmca.org or $1500 to sdcard.org.

http://www.sandisk.com/download/Product%20Manuals/MMCProdMn_5.1.pdf
http://www.sandisk.com/download/Product%20Manuals/Product%20ManualSDCardv1.7.pdf