Page Comparison

...

• FATFS is a file system library that allows for file management on the SD card

• It requires a couple of low level functions specific to the hardware platform in order to operate

  • See

    Code Block
    sd_diskio.h, bsp_driver_sd.h

• File names by default are 8.3 format (max 8 character file name, max 3 character file extension)

• There are two utility functions written the abstract over the FATFS API, one for reading, one for writing found in log_util.h

  • Code Block
    FRESULT logWrite(char*, void*, UINT, UINT*); FRESULT logRead(char*, void*, UINT, UINT*);

Debugging

• Ensure SD cards are formatted using MS-DOS (FAT32) using MBR (Master Boot Record)

• Ensure SD card is not over 32GB in capacity

• Ensure the clock for SDMMC is set according to your SD card speed, (i.e. if your card is rated for 10MB/s speed, set the SDMMCCLK to just under that, something like 8MB/s with 0 clock divider)

• Ensure file names follow 8.3 format

• All FATFS function calls return a FRESULT error code, printing them out is helpful

  • FATFS Error Codes: http://elm-chan.org/fsw/ff/doc/rc.html

Links

SD Drivers PR: https://github.com/UWARG/efs-zeropilot-3.5/pull/45

...

HAL Docs for STM32 Nucleo L5: https://www.st.com/resource/en/user_manual/um2659-description-of-stm32l5-hal-and-lowlayer-drivers-stmicroelectronics.pdf

FATFS Docs: http://elm-chan.org/fsw/ff/

FATFS Driver unit tests: http://elm-chan.org/fsw/ff/res/app4.c