We are trying to to read and write to a SD card. We are using the STM32F50N8. Find below attached the schematic for the SD card and the GPIO. We have set it up the same we as mentioned here (SD 4 bit wide mode) - https://www.youtube.com/watch?v=

[PMold.1]

Hi,

We are trying to to read and write to a SD card.

We are using the STM32F50N8. Find below attached the schematic for the SD card and the GPIO.

We have set it up the same we as mentioned here (SD 4 bit wide mode) - https://www.youtube.com/watch?v=I9KDN1o6924&ab_channel=STMicroelectronics

However, FR returns not ready.

Can you please advice us on how to fix this.

Many thanks,

[Tesla DeLorean]

What's an STM32F50N8 ? a STM32F750N8?

Not Ready typically comes from not having the right GPIO associated GPIO_SDMMC_DET, and that is properly initialized.

Check that it goes low properly when the card is present, that you need the PULL-UP enabled, as you don't have an external one. You can remove the checking code also if the pin doesn't report correctly

Also no external pull-ups on the D0,D1,D2,D3,CMD card side, would have suggested those, so definitely ensure the internal pull-ups on STM32 side.

[PMold.1]

Sorry STM32F750N8. I made these external pull ups with 10K resistors. I also added a pull up to the GPIO_SDMMMC_DET line and it goes low when the SD card is inside. I also made the internal pins to pull up as shown below. However, it still returns not ready. The line it breaks on is attached below. 

 

[PMold.1]

For this project I was using FreeRTOS. Hence, the issue.

All I had to do to fix it was to increase the stack size of the task.