schematics for microSd on SDMMC

[MLe M.1]

Hello,

Do you have schematics suggestion for using a microSD on the SDMMC interface of the STM32L476? The reference manuel only shows data with 8 lines while the microSD has only 4 lines with data3 share with card detect.

Do I only need to ignore the card detect and configure bus has 4 lines?

Best regards

Mich

[SofLit · Accepted solution]

Hello,

For hardware, you can refer to  STM32L476G-EVAL Schematics downloadable from this link.

For Software you can refer to the example available in STM32L4 cube under the path: Projects\STM32L476G-EVAL\Applications\FatFs\FatFs_uSD_Standalone

Hope this does answer your question.

[Tesla DeLorean]

Generally the interface takes 6 pins. with a 7th GPIO pin connected to a mechanical switch on the SD Card holder/socket to indicate the card is present. Use this so you can detect removal, etc.

Now MMC+ cards and eMMC can support 8-bit modes, but the former kind of disappeared rather quickly as a standard, and sockets are hard to find. Basically everyone pivoted into the MicroSD form-factor and 50+ MHz bandwidths.