SD Cards - Quick Question

Jan 12, 2010 3 Replies

Anyone know if SD Memory cards have internal unique serial numbers that can be read by their host systems? I'm not so much worried (right now) about the electronics, code or licensing agreements -- only if it is possible?



I thought I read somewhere that they had an internal laser-engraved, (unique?) serial number. That might have been for CompactFlash cards, though. I really just don't recall.



Thanks for the help. References / web links are welcome!



-mpm


You want the CID. Take a look here,

Cheers

Thanks. The CID register does indeed look like it will serve our purposes.

I'm assuming this register is read-only, and is factory populated during manufacture? Is that true?

I went looking for write privledges for CID, but did not see them in the document. If you know, it would save some head-scratching.

But even if CID can be altered after SD Card manufacture, we would still probably be OK with that. We just need an audit trail for some data to be released on SD card, and CID looks like it will do nicely.

Thanks again.

-mpm

From what I understand the CID was for multiple cards on a bus, but the latest spec has dropped support for multiple cards. As far as I know the CID is still present and is hard coded.

Look at msdn , there are calls that allow you to send low level commands to the card.

Cheers

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