FatFS

FatFs is a lightweight software library for small systems that implements FAT file system support. It's written in ANSI C89 and has no dependencies other than a minimal C environment. It'll compile out of the box in virtually any environment.

FatFs itself does not provide the device/media-specific Storage Device Controls. Those have to come from the device implementer. The SDSPI submodule provides these functions for FatFs. Four files are provided: sdcard.c, sdcard.h, diskio.c, and board.h.

FatFs Media Access Interface.

FatFs Media Access Interface.

FatFs Configuration

FatFs is very configurable, so you can trade options for footprint. All configuration options are well-documented and centralized in the ffconf.h file. Relative to the default settings, I modified the following:

  • Enable FF_USE_FIND: filtered directory read functions, f_findfirst() and f_findnext().
  • Enable FF_USE_STRFUNC: string functions, f_gets(), f_putc(), f_puts(), and f_printf().
  • Enable FF_FS_RPATH: support for relative paths.
  • Enable FF_FS_NORTC: I disabled the timestamp feature. I will revisit this when I bring up RTC on BoxLambda.

https://github.com/epsilon537/fatfs/blob/boxlambda/source/ffconf.h

FatFs_Test

FatFs itself does not provide a test suite, but I found a simple test sequence in another project. I used that code as the starting point for a BoxLambda fatfs_test.