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STM32F4 MMC support

Associate III
Posted on March 16, 2016 at 11:21

Dear support, 

    looking at this forum there are several request about MMC support on STM32. 

I wonder whether ST is going to release a working driver for this kind of devices. 

Thank you in advance. 

Nesrine M_O
Lead II
Posted on March 16, 2016 at 15:09

Hi peregrinus,

We are aware about your request, and I confirm that there is a plan to support MMC on HAL but not yet available.


Associate II
Posted on March 17, 2016 at 12:18

Good morning,

I was planing to use STM32F427 + emmc for a new desing.

But after doing a search in the forum it seems that it's not a good idea.

Moreover, reading the documentation in the point related it says:

 3.30 Secure digital input/output interface (SDIO)

 An SD/SDIO/MMC host interface is available, that supports MultiMediaCard System

 Specification Version 4.2 in three different databus modes: 1-bit (default), 4-bit and 8-bit.

But present emmc devices are version 4.5 or 5, would they work?

Should I forget about using emmc and use instead SD card for my new desing?

Posted on March 17, 2016 at 15:31

ST has some odd priorities, I wish sometimes they'd focus some of the thousands of man hours wasted on other projects, and get some of the fundamental examples working and up to date.

I suspect it will work fine if someone spends some time and effort on it, people should perhaps stop relying on ST and others to furnish code. I think there is a general over reliance on that.

If you don't have mechanical issues with SD cards (vibration, insertion, retention, size, etc), they probably offer the best long term viability and field upgrade avenues. Even on a board with MMC I'd be tempted to place an SD socket/holder footprint I could populate as a BOM change.

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