HAL_SD_ERROR_TX_UNDERRUN when using FATFS

[ABatt.1]

I'm trying to use FATFS on NUCLEO-F401RE to write a file into the SD Card.

I generated the project into cube MX and added thi code before the while(1) loop:

 /* USER CODE BEGIN 2 */
  temp = f_mount(&StrutturaCtrFS,"",1);
  if(FR_OK != temp){
	  while(1);
  }
 
  temp = f_open(&File_CFG,"Cfg.ini", FA_READ | FA_WRITE | FA_CREATE_ALWAYS);
  if(FR_OK != temp){
	  while(1);
  }
 
  temp = f_write(&File_CFG, "CIAO",4,0);
  if(FR_OK != temp){
	  while(1);
  }
  f_close(&File_CFG);
  /* USER CODE END 2 */

it stops in F_wirte instruction. With debugger I founded that the error is a HAL_SD_ERROR_TX_UNDERRUN in HAL_SD_WriteBlocks (line 782 in stm32f4xx_hal_sd.c).

Attached there is my .ioc file

The SD is connected as this:

MISO -> PC8 (SDIO_DO)

MOSI -> PD2 (SDIO_CMD)

CLK -> PC12 (SDIO_SK)

CS -> PC3 ( GPIO OUTPUT HIGH)

also (because my SD card slot doesn't have a SD_presence pin) I put PC9 of FATFS to GND.

What's wrong in this project ?

Thanks to all.

[ABatt.1]

Hi to all,

After triple checked all (configuration and connection) I found the mistake.

The clock is too fast!

With oscilloscope on PC12 I see that the clock was not a square wave:

So I changed "SDIOCLK clock divide factor" in CubeMX from 0 to 32. Now the clock is ok:

and the file was successfully written into SD card.

this limitation on clock is due to the NUCLEO-board or my SD CARD/slot ?

I have a 10k pullup resistor on MISO, MOSI and SCK, but as I can see from the wave form is not a pull-up issue.

Attached there is new .ioc file

Thanks to all.

AB