SD Cards

Does anyone out there have any IP and documents on how to use SD cards ?


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Reply to
Victor Schutte
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Victor, the answer to your question is "Yes". But that's was obvious, isnt it?

If you want that somebody replies to you and says: "here you go please take free IP for your commercial product" - then that answer usually do not get. Even if there is free IP, using it may take more support than you save.

SD is little different from MMC so plain MMC IP will not work for SD, there was supposed to be MMC IP at opencores but the project creator never uploaded any files and project was deleted later.


Reply to
Antti Lukats

IIRC SD is a superset of MMC.

An SD card is an MMC card with a few extra pins, access modes and a security scheme.

I heard the latter was soon cracked, but the keepers of the spec behave as if it were not. That is, you have to pay to see it. Which is a bad sign: security should be ensured by keys, not knowledge of the locking mechanism. After all, anyone can find out how Chubb locks work, but it won't tell you which key you need for a particular lock.

In short you have an MMC card with the option of faster access modes. These shouldn't be too hard to add if you already know MMC.

The security features are not worth bothering with, IMHO.

Reply to


yes and no.

if you have IP core that supports MMC then inserting SD card would yield the card to not be recognized at all.

its mostly similar, but in order to support MMC/SD there is some additional things required to make both work.

the basics sure are the same

Antti PS MMC spec ver 4 adds 8bit - per clock mode and 52MHz max clock so the max transfer rates are getting higher! MMC_ver4 uses 6 more pins in addition to the SD card pins

Reply to
Antti Lukats

I could have thought a major point would be to produce something compatible with MMC and not annoy existing customers with loads of MMC equipment.

Perhaps the SD spec just allows you to read MMC cards instead of having to replace them.

I wish they would just define card standards with an array of pin positions for D0...Dn and leave it up to the reader to detect and use whatever width of data bus both can support.

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