Example SD Card file write example using Azure RTOS FileX with SDIO is not working for STM32F767ZI Nucleo board

[rdevisetti]

Example SD Card file write example using Azure RTOS FileX with SDIO is not working for STM32F767ZI Nucleo board. Please let me know how to fix it. I used the Fx_uSD_File_Edit example is used. It is failing in getting the SCR register value on the SD Card. Anyone have any idea on this issue? Am I missing anything? Even the same thing is happening with the project created by myself for STM32F767ZI Nucleo board. What can be the solution?

[AScha.3 · Accepted solution]

Probably hardware problem; how you connect sd-card ? (pic ?)

wires? lenght?

pin mode?

1 or 4-bit mode?

[rdevisetti]

Wires connected are 8 and the length of the wires may be around 30 cm. I had selected the SDMMC1 peripheral for SD card interface. Using 4-bit SD mode.

Pin Mode: Alternate Function Push Pull

Pin 2 SDMMC_D0 PC8
Pin 4 SDMMC_D1 PC9
Pin 6 SDMMC_D2 PC10
Pin 8 SDMMC_D3 PC11
Pin 10 SDMMC_CK PC12
Pin 12 SDMMC_CMD PD2

Pin 11 GND

Pin 7 VCC (+3.3V)

[AScha.3]

Ok, just think: the sd-card works at full speed with 25MHz data clock/rate , so short connection is needed.

From my tests i can tell: connected to the nucleo pin header with 70mm wires , no connection to card.

Same adapter with 20mm wires working.

And all pins set on medium or medium/high speed, pullups ON .

And at first 1-bit mode (is less critical than 4-bit mode).

And dont write or mkfs at first , only read (existing file on card) ! ..until this working fine.