STM32F405 and SDIO

Development Boards MicroMod
1

Has anyone managed to get the SDIO interface working with the STM32F405 processor board. I’m using the ATP carrier board and a microSD card breakout, and have connected pins PD2 to the card’s CMD line, PC8 to the card’s DATA/D0 line and PC12 to the card’s CLK/SCK line. 3.3V and ground are also connected to the card. As far as I can tell, this should be enough for 1-bit SDIO communications.

I’ve tested with a modified version of this code, which is originally for an STM board: https://github.com/colosimo/fatfs-stm32

The schematic for the STM32F405 board shows the PD2 pin connected to other components. Does this complicate use of SDIO?

2

Looking again at the processor board schematic, it seems that I was misinterpreting how the pins are broken out.

My impression is that the SDIO_CLK pin is the problem as it’s connected to the flash chip and otherwise not broken out on the connector.