eMMC in 8 bits Wide bus mode

[Radwan Neouchi]

Posted on January 04, 2017 at 15:35

Hello,

I'm using a STM32L4 and CubeMx to generate eMMC code, either the 8 bits wide bus mode configuration isn't supported and should be configured manually.

I was able, with few code modification, to use the SD auto generated code to communicate with the eMMC in 4 bits mode, but when trying to move to 8 bits mode my f_mount() function returns '

http://elm-chan.org/fsw/ff/en/rc.html#ns

' error.

To adapt the SD code to an eMMC i've added few eMMC appropriate commands to configure its Power Class and bus wide by a switch command and it worked without any issue.

To move to 8 bits mode, I added some more current (needed as said in the eMMC datasheet) and passed the 8 bits mode argument instead of 4 bits one. Then in the HAL_SD_MspInit() and HAL_SD_MspDeInit() functions I added the 4 additive used GPIO pins init and DeInit procedure...

What are the manually modifications needed to use the 8 bits bus wide mode? And did I missed some of this neede modifications?

Regards.

[dirkvermaak]

Posted on January 17, 2017 at 13:10

Hi, we are currently trying the exact same thing and awaiting the imminent release of the STM32F4 eMMC drivers. May I ask exactly what changes you made to get the SD driver working with your eMMC?

Many Thanks,

Dirk