Usage of both SDIO interface at the same time in STM32H747

Rekhas19 · ‎2023-12-15

Hi, I observed a limitation in the STM32H7 reference manual saying that

"The current version of the SDMMC supports only one SD/SDIO/e•MMC card at any one
time and a stack of e•MMC."

So my application requires to control two SDIO slaves from both SDIO interfaces of STM32H747 at the same time, Is this realizable?

FBL · ‎2023-12-15

Hello @Rekhas19

Indeed, SDMMC interface only supports one card at a time, meaning that a device can only read from or write to one card at a time.

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Rekhas19 · ‎2023-12-25

Hi Belaid,

Thank you for replying to my query.

When i saw the HAL and LLs of STM32H7 , i could not find any reference to CMD5, CMD52 and CMD53,which are SDIO specific functions. Please excuse me, I am very new to SDIO protocol. Can you please point to any reference API or example for those commands?

AScha.3 · ‎2023-12-25

Hi,

As I understand the manual, every sdmmc interface can use one card, so using both sdmmc can connect to two SD cards, one on each sdmmc interface.

You want to use fatfs - or what? So give them two different drive names, maybe 0 and 1 .

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FBL · ‎2023-12-25

You can find SD Card Specific commands here.
I hope this helps!

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