Hi, I have a few questions regarding these cards.

Do they have 7 or 13 pins?

Scandisc datasheet v 1.3 page 14 has a 7 pin diagram, but the mmc standard  jesd84-a441 has a 13 pin diagram. Looks confusing to me , since they both refer to mmc cards.

The datasheet is found at

Is there any updated version of that info? I tried to call a sales number for direct buy in appendix a but it has been disconnected.

I would like to use MMC for some data distribution and don’t want it to be copied. Can I use MMC or MMC secure is the only option I have?  If data is copy protected, can it be read through SPI or I need to use normal card communication?

Thank you


they are 7 pin but mmc cards have been discontinued for several years now. the SD form factor pretty much killed mmc

So, in case I would like to develop a product and need memory I would be stuck with SD? Don’t they have some $2000 membership fee and as a start up that means the world to me? There isn’t even any open standard on them,  or am I missing something?

By the way they really aren’t produced that much or just demand is low and market share is quite neglible?

Thank you for the reply drlucky. The truth is bitter.

yes, the sd association has a fee and you would have to pay it if you need some developmental things. there are available spec sheets and standards for implementing them in your design but you would get them from the distributors where you would purchase the cards. go with OEM cards. no one provides these documents for retail products. 

SD is probably the largest manufactured card in the flash market. it is used in more devices and his higher number sells than any other flash form factor.

if you want to design on something more open look into compact flash however you will still run into some similar issues as sd.

Hi drlucky,

I have been thinking for a while whether to use mmc or SD about my product, and this standard fee had put the idea off my head till now. I can’t even find mmc on the market now and their price is almost the same if not higher than SD, so what’s the point? Compact flash seem to be even more expensive :frowning:

Anyway, when you mean getting the datasheet from oem, whom do you have in mind? SanDisk wont give any datasheet to me, would it? The last version of Sandisk for SD that I have been able to find is v1.9 of 2003. It might be kind of outdated now, isn’t it?

Thank you.

try contacting one of the sandisk OEM distributors they should have the data sheets.