SD runs in SPI or qSPI mode, MMC runs in MMC or SPI mode, with the default being MMC.
MMC does a 400Khz clock lock startup, then you send it a command to switch modes, from then on it acts much like SD. I don't have the info in front of me, but I have the docs at home.
I didn't say that my driver works with every MMC card. But, it does work for some.
Back in the day, this was (and still is somewhat) and big issue for driver programmers. It is not true that all MMC cards work the same way and follow the protocol.
Since the release of the SD 2.0 protocol all cards are now required to follow a strict set of standards. The original MMC and SD 1.0 protocols allowed a lot of *flexibility*.
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That is can you point me to the MMC spec to educate me about the MMC protocol?
rich
MMC does a 400Khz clock lock startup, then you send it a command to switch modes, from then on it acts much like SD. I don't have the info in front of me, but I have the docs at home.
Back in the day, this was (and still is somewhat) and big issue for driver programmers. It is not true that all MMC cards work the same way and follow the protocol.
Since the release of the SD 2.0 protocol all cards are now required to follow a strict set of standards. The original MMC and SD 1.0 protocols allowed a lot of *flexibility*.