ELM - FatFs Generic FAT File System Module

FatFs is a generic FAT file system module for small embedded systems. The FatFs is written in compliance with ANSI C and completely separated from the disk I/O layer. Therefore it is independent of hardware architecture. It can be incorporated into low cost microcontrollers, such as AVR, 8051, PIC, ARM, Z80, 68k and etc..., without any change. Petit FatFs module is also available here.

Features

Windows compatible FAT file system.
Platform independent. Easy to port.
Very small footprint for code and work area.
Various configuration options:
- Multiple volumes (physical drives and partitions).
- Multiple ANSI/OEM code pages including DBCS.
- Long file name support in ANSI/OEM or Unicode.
- RTOS support.
- Multiple sector size support.
- Read-only, minimized API, I/O buffer and etc...

Application Interface

FatFs module provides following functions to the applications. In other words, this list describes what FatFs can do to access the FAT volumes.

f_mount - Register/Unregister a work area
f_open - Open/Create a file
f_close - Close a file
f_read - Read file
f_write - Write file
f_lseek - Move read/write pointer, Expand file size
f_truncate - Truncate file size
f_sync - Flush cached data
f_opendir - Open a directory
f_readdir - Read a directory item
f_getfree - Get free clusters
f_stat - Get file status
f_mkdir - Create a directory
f_unlink - Remove a file or directory
f_chmod - Change attribute
f_utime - Change timestamp
f_rename - Rename/Move a file or directory
f_chdir - Change current directory
f_chdrive - Change current drive
f_getcwd - Retrieve the current directory
f_forward - Forward file data to the stream directly
f_mkfs - Create a file system on the drive
f_fdisk - Divide a physical drive
f_gets - Read a string
f_putc - Write a character
f_puts - Write a string
f_printf - Write a formatted string
f_tell - Get the current read/write pointer
f_eof - Test for end-of-file on a file
f_size - Get size of a file
f_error - Test for an error on a file

Disk I/O Interface

Since the FatFs module is completely separated from disk I/O layer, it requires following functions at least to access the physical media. When O/S related feature is enabled, it will require process/memory functions in addition. However the low level disk I/O module is not a part of FatFs module so that it must be provided by user. The sample drivers are also available in the resources.

disk_initialize - Initialize disk drive
disk_status - Get disk status
disk_read - Read sector(s)
disk_write - Write sector(s)
disk_ioctl - Control device dependent features
get_fattime - Get current time

Resources

The FatFs module is a free software opened for education, research and development. You can use, modify and/or redistribute it for personal projects or commercial products without any restriction under your responsibility. For further information, refer to the application note.

FatFs User Forum
Read first: FatFs module application note August 27, 2012
Nemuisan's Blog (Well written implementations for STM32F/SDIO and LPC2300/MCI)
ARM-Projects by Martin THOMAS (examples for LPC2000, AT91SAM and STM32)
FAT32 Specification by Microsoft (The reference document on FAT file system)
How to Use MMC/SDC
Benchmark 1 (ATmega64/9.2MHz with MMC via SPI, HDD/CFC via GPIO)
Benchmark 2 (LPC2368/72MHz with MMC via MCI)
Demo movie of an application (this project is in ffsample.zip/lpc23xx)