How to integrate SPI sd card on STM32L452CC?

[MFrie.6]

I have a custom board with the l452cc controller. I am trying to run an sd card with fatfs through spi. I have generated cubemx fatfs files, but there is no interface layer for spi to fatfs. Are there some examples I can reference off of, or what is the best way to approach this?

Thanks.

[MFrie.6]

Thanks for the input, I'll see how far I get and ask back if I have questions. Thanks

[HDaji.1]

Is FatFS able to handle if SD card's sector size is not 512?

[HDaji.1]

If you make it work, please also post your tech details here.

[MFrie.6]

Well I'm making some progress. I implimented the NUCLEO-L452RE example project basically. 'BSP_SD_INIT()' returns success. f_mount however returns 'FR_NO_FILESYSTEM'. Sd card is a 16GB formatted with exFat currently. I have tried formatting it with FAT32 as well, with no success. Is this a low level problem, or is there something fundamentally wrong with my implimentation. Here is the section of applicable code.

static void SDCard_Config(void) { 
  /* Initialize the SD */
  if (BSP_SD_Init() != MSD_OK) {
#if DEBUG
    debug_printf("BSP_SD_INIT_FAILED\r\n");
#endif
  } else {
#if DEBUG
    debug_printf("BSP_SD_INIT_SUCCESS\r\n");
#endif
  }
}

void MX_FATFS_Init(void)
{
  /*## FatFS: Link the USER driver ###########################*/
  retUSER = FATFS_LinkDriver(&SD_Driver, USERPath);
 
  /* USER CODE BEGIN Init */
  /* additional user code for init */
  /* USER CODE END Init */
}

MX_FATFS_Init();
  SDCard_Config();
  FIL fil;        /* File object */
  char line[100]; /* Line buffer */
  FRESULT fr;     /* FatFs return code */
 
  /* Give a work area to the default drive */
  fr = f_mount(&SD_FatFs, "", 1);
  if (fr) {
    __NOP();
  }
 
  /* Open a text file */
  fr = f_open(&fil, "message.txt", FA_READ);
  if (fr) {
    __NOP();
  }
 
  /* Read every line and display it */
  while (f_gets(line, sizeof line, &fil)) {
    debug_printf(line);
  }
 
  /* Close the file */
  f_close(&fil);

Thanks

[MFrie.6]

Here is a logic capture of the above code. You will have to rename 'SD_init.sal.txt' to 'SD_init.sal', thanks to a forum quirk.

[MFrie.6]

So apparently 'Check boot record signature' is what is firing the error.

if (ld_word(fs->win + BS_55AA) != 0xAA55) return 3;	/* Check boot record signature (always placed here even if the sector size is >512) */

It would almost seem like I have a spi driver problem, but if I look in 'fs->win' there appears to be some random data lines 440 to 461 in the sector. So not sure if it is a driver problem or not.

[MFrie.6 · Accepted solution]

Ok so it was a driver problem. I haven't pinned it down yet, but it has to do with the dma, because when I use normal spi mode, it will do a basic read write. So the process to get an sd card working is this:

Generate fatfs files with cubemx

Copy BSP package in from the adafruit sd shield example

Write a spi driver, and tie it into the BSP package

In theory it should then work. I may have missed a few details, so feel free to ask if you have any questions.

[HDaji.1]

Are you able to read/write file with large size, like a few tens or even hundreds bytes?

How do you format the SD card? What is the sector size?

[MFrie.6]

I haven't tried much besides a basic hello world text file. I will see here at some point. The card is formatted with FAT, and I have tried exFat too and that works. I will post back after I have tried some bigger files.

[MFrie.6]

Well I don't know if this gets what you are wanting to know but here is a piece of code that I ran.

  BYTE buf[2048];
  memset(buf, 0x4c, sizeof(buf));
  UINT br, bw;
  fr = f_write(&fil, buf, sizeof(buf), &bw);

The file when I look at it is filled with 0x4c, so it seems like it is working.