FatFS是壹個專為小型嵌入式系統設計的通用FAT文件系統模塊。FatFs具有較高的可配置性，最小配置僅使用1K的RAM空間，非常適用於嵌入式系統。FatFs 的編寫遵循ANSI C，並且完全與磁盤I/O層分開。因此，它獨立(不依賴)於硬件架構。它可以被嵌入到低成本的微控制器中，如AVR, 8051, PIC, ARM, Z80, 68K 等等，而不需要做任何修改。
特點
Windows兼容的FAT文件系統
不依賴於平臺，易於移植
代碼和工作區占用空間非常小
多種配置選項：
多卷(物理驅動器和分區)
多ANSI/OEM代碼頁，包括DBCS
在ANSI/OEM或Unicode中長文件名的支持
RTOS的支持
多扇區大小的支持
只讀，最少API，I/O緩沖區等等
FatFs的源代碼只有幾個文件:diskio.c,ff.c,ff_util.c,tff.c及頭文件。diskio.c是磁盤操作的代碼文件(這個文件是移植時要實現的)，ff.c是壹般FatFs的代碼文件，tff.c是微型FatFs的代碼文件，ff_util.c是幾個輔助函數。integer.h是內部基本類型的定義，ff.h是壹般FatFs包含的頭文件，tff.h是微型FatFs包含的頭文件。
[cpp] view plaincopy在CODE上查看代碼片派生到我的代碼片
#if _FATFS_TINY != 1
#include <fatfs/src/ff.h>
#else
#include <fatfs/src/tff.h>
#endif
#include <fatfs/src/ff_util.h>
微型FatFs配置最小時僅占用內存1KB，但它是壹個只讀的FAT系統。
FatFs的配置文件是fatfs_config.h:
[cpp] view plaincopy在CODE上查看代碼片派生到我的代碼片
//------------------------------------------------------------------------------
// General Definitions (previously in ff.h)
//------------------------------------------------------------------------------
#define _FATFS_TINY 0
/* When _FATFS_TINY is set to 1, fatfs is compiled in Tiny mode
/ Else, it is compiled in normal mode
/ Tiny FatFs feature : Very low memory consumption, suitable for small memory
/ system. (1KB RAM) : Supports only single drive, no disk format,
/ only read functions, no write functions */
//------------------------------------------------------------------------------
// Definitions for normal FATFS (previously in ff.h)
//------------------------------------------------------------------------------
#if _FATFS_TINY == 0
#define _MCU_ENDIAN 2
/* The _MCU_ENDIAN defines which access method is used to the FAT structure.
/ 1: Enable word access.
/ 2: Disable word access and use byte-by-byte access instead.
/ When the architectural byte order of the MCU is big-endian and/or address
/ miss-aligned access results incorrect behavior, the _MCU_ENDIAN must be set to 2.
/ If it is not the case, it can also be set to 1 for good code efficiency. */
#define _FS_READONLY 0
/* Setting _FS_READONLY to 1 defines read only configuration. This removes
/ writing functions, f_write, f_sync, f_unlink, f_mkdir, f_chmod, f_rename,
/ f_truncate and useless f_getfree. */
#define _FS_MINIMIZE 0
/* The _FS_MINIMIZE option defines minimization level to remove some functions.
/ 0: Full function.
/ 1: f_stat, f_getfree, f_unlink, f_mkdir, f_chmod, f_truncate and f_rename are removed.
/ 2: f_opendir and f_readdir are removed in addition to level 1.
/ 3: f_lseek is removed in addition to level 2. */
#define _USE_STRFUNC 0
/* To enable string functions, set _USE_STRFUNC to 1 or 2. */
#define _USE_FSINFO 1
/* To enable FSInfo support on FAT32 volume, set _USE_FSINFO to 1. */
#define _USE_SJIS 1
/* When _USE_SJIS is set to 1, Shift-JIS code transparency is enabled, otherwise
/ only US-ASCII(7bit) code can be accepted as file/directory name. */
#define _USE_NTFLAG 1
/* When _USE_NTFLAG is set to 1, upper/lower case of the file name is preserved.
/ Note that the files are always accessed in case insensitive. */
#define _USE_MKFS 1
/* When _USE_MKFS is set to 1 and _FS_READONLY is set to 0, f_mkfs function is
/ enabled. */
#define _DRIVES 2
/* Number of logical drives to be used. This affects the size of internal table. */
#define _MULTI_PARTITION 0
/* When _MULTI_PARTITION is set to 0, each logical drive is bound to same
/ physical drive number and can mount only 1st primaly partition. When it is
/ set to 1, each logical drive can mount a partition listed in Drives[]. */
//------------------------------------------------------------------------------
// Definitions for normal FATFS TINY (previously in tff.h)
//------------------------------------------------------------------------------
#else
#define _MCU_ENDIAN 2
/* The _MCU_ENDIAN defines which access method is used to the FAT structure.
/ 1: Enable word access.
/ 2: Disable word access and use byte-by-byte access instead.
/ When the architectural byte order of the MCU is big-endian and/or address
/ miss-aligned access results incorrect behavior, the _MCU_ENDIAN must be set to 2.
/ If it is not the case, it can also be set to 1 for good code efficiency. */
#define _FS_READONLY 1
/* Setting _FS_READONLY to 1 defines read only configuration. This removes
/ writing functions, f_write, f_sync, f_unlink, f_mkdir, f_chmod, f_rename,
/ f_truncate, f_getfree and internal writing codes. */
#define _FS_MINIMIZE 0
/* The _FS_MINIMIZE option defines minimization level to remove some functions.
/ 0: Full function.
/ 1: f_stat, f_getfree, f_unlink, f_mkdir, f_chmod, f_truncate and f_rename are removed.
/ 2: f_opendir and f_readdir are removed in addition to level 1.
/ 3: f_lseek is removed in addition to level 2. */
#define _USE_STRFUNC 0
/* To enable string functions, set _USE_STRFUNC to 1 or 2. */
#define _USE_FSINFO 1
/* To enable FSInfo support on FAT32 volume, set _USE_FSINFO to 1. */
#define _USE_SJIS 1
/* When _USE_SJIS is set to 1, Shift-JIS code transparency is enabled, otherwise
/ only US-ASCII(7bit) code can be accepted as file/directory name. */
#define _USE_NTFLAG 1
/* When _USE_NTFLAG is set to 1, upper/lower case of the file name is preserved.
/ Note that the files are always accessed in case insensitive. */
#define _USE_FORWARD 0
/* To enable f_forward function, set _USE_FORWARD to 1. */
#define _FAT32 1
/* To enable FAT32 support in addition of FAT12/16, set _FAT32 to 1. */
#endif
//------------------------------------------------------------------------------
// Other definitions
//------------------------------------------------------------------------------
/*-----------------------------------------------------------------------*/
/* Correspondence between drive number and physical drive */
/* Note that Tiny-FatFs supports only single drive and always */
/* accesses drive number 0. */
#define DRV_MMC 0
#define DRV_SDRAM 1
#define DRV_ATA 2
#define DRV_USB 3
#define SECTOR_SIZE_SDRAM 512
#define SECTOR_SIZE_SDCARD 512