STM32移植FATFS文件系统的一般步骤：
由于存储介质的不同，导致FATFS文件系统底层函数的移植问题显得很复杂，但是还是有一定的章法的，本文参考野火的例程，以SPI_FLASH为例子，来简要的介绍一下FATFS的diskio.c和ffconf.h文件的配置
ffconf.h文件：
这个文件的配置需要注意点：
- 141行_VOLUMES选择设备数量，比如同时有SPI_FLASH，SD卡两个逻辑驱动器，那就应该给2
- _USE_MKFS要使能，这个宏定义决定是否可以使用格式化函数f_mkfs,如果你之前没有格式化，那一定会用到这个函数的
- 163行_MAX_SS，这个宏定义决定了一个扇区的字节数量
完成以上三步，那SPI_FLASH的ffconf文件就算移植完成了，配置好的文件如下：
/*---------------------------------------------------------------------------/
/ FatFs - FAT file system module configuration file R0.11a (C)ChaN, 2015
/---------------------------------------------------------------------------*/
#define _FFCONF 64180 /* Revision ID */
/*---------------------------------------------------------------------------/
/ Function Configurations
/---------------------------------------------------------------------------*/
#define _FS_READONLY 0
/* This option switches read-only configuration. (0:Read/Write or 1:Read-only)
/ Read-only configuration removes writing API functions, f_write(), f_sync(),
/ f_unlink(), f_mkdir(), f_chmod(), f_rename(), f_truncate(), f_getfree()
/ and optional writing functions as well. */
#define _FS_MINIMIZE 0
/* This option defines minimization level to remove some basic API functions.
/
/ 0: All basic functions are enabled.
/ 1: f_stat(), f_getfree(), f_unlink(), f_mkdir(), f_chmod(), f_utime(),
/ f_truncate() and f_rename() function are removed.
/ 2: f_opendir(), f_readdir() and f_closedir() are removed in addition to 1.
/ 3: f_lseek() function is removed in addition to 2. */
#define _USE_STRFUNC 0
/* This option switches string functions, f_gets(), f_putc(), f_puts() and
/ f_printf().
/
/ 0: Disable string functions.
/ 1: Enable without LF-CRLF conversion.
/ 2: Enable with LF-CRLF conversion. */
#define _USE_FIND 0
/* This option switches filtered directory read feature and related functions,
/ f_findfirst() and f_findnext(). (0:Disable or 1:Enable) */
#define _USE_MKFS 1
/* This option switches f_mkfs() function. (0:Disable or 1:Enable) */
#define _USE_FASTSEEK 0
/* This option switches fast seek feature. (0:Disable or 1:Enable) */
#define _USE_LABEL 0
/* This option switches volume label functions, f_getlabel() and f_setlabel().
/ (0:Disable or 1:Enable) */
#define _USE_FORWARD 0
/* This option switches f_forward() function. (0:Disable or 1:Enable)
/ To enable it, also _FS_TINY need to be set to 1. */
/*---------------------------------------------------------------------------/
/ Locale and Namespace Configurations
/---------------------------------------------------------------------------*/
#define _CODE_PAGE 932
/* This option specifies the OEM code page to be used on the target system.
/ Incorrect setting of the code page can cause a file open failure.
/
/ 1 - ASCII (No extended character. Non-LFN cfg. only)
/ 437 - U.S.
/ 720 - Arabic
/ 737 - Greek
/ 771 - KBL
/ 775 - Baltic
/ 850 - Latin 1
/ 852 - Latin 2
/ 855 - Cyrillic
/ 857 - Turkish
/ 860 - Portuguese
/ 861 - Icelandic
/ 862 - Hebrew
/ 863 - Canadian French
/ 864 - Arabic
/ 865 - Nordic
/ 866 - Russian
/ 869 - Greek 2
/ 932 - Japanese (DBCS)
/ 936 - Simplified Chinese (DBCS)
/ 949 - Korean (DBCS)
/ 950 - Traditional Chinese (DBCS)
*/
#define _USE_LFN 0
#define _MAX_LFN 255
/* The _USE_LFN option switches the LFN feature.
/
/ 0: Disable LFN feature. _MAX_LFN has no effect.
/ 1: Enable LFN with static working buffer on the BSS. Always NOT thread-safe.
/ 2: Enable LFN with dynamic working buffer on the STACK.
/ 3: Enable LFN with dynamic working buffer on the HEAP.
/
/ When enable the LFN feature, Unicode handling functions (option/unicode.c) must
/ be added to the project. The LFN working buffer occupies (_MAX_LFN + 1) * 2 bytes.
/ When use stack for the working buffer, take care on stack overflow. When use heap
/ memory for the working buffer, memory management functions, ff_memalloc() and
/ ff_memfree(), must be added to the project. */
#define _LFN_UNICODE 0
/* This option switches character encoding on the API. (0:ANSI/OEM or 1:Unicode)
/ To use Unicode string for the path name, enable LFN feature and set _LFN_UNICODE
/ to 1. This option also affects behavior of string I/O functions. */
#define _STRF_ENCODE 3
/* When _LFN_UNICODE is 1, this option selects the character encoding on the file to
/ be read/written via string I/O functions, f_gets(), f_putc(), f_puts and f_printf().
/
/ 0: ANSI/OEM
/ 1: UTF-16LE
/ 2: UTF-16BE
/ 3: UTF-8
/
/ When _LFN_UNICODE is 0, this option has no effect. */
#define _FS_RPATH 0
/* This option configures relative path feature.
/
/ 0: Disable relative path feature and remove related functions.
/ 1: Enable relative path feature. f_chdir() and f_chdrive() are available.
/ 2: f_getcwd() function is available in addition to 1.
/
/ Note that directory items read via f_readdir() are affected by this option. */
/*---------------------------------------------------------------------------/
/ Drive/Volume Configurations
/---------------------------------------------------------------------------*/
#define _VOLUMES 2
/* Number of volumes (logical drives) to be used. */
#define _STR_VOLUME_ID 0
#define _VOLUME_STRS "RAM","NAND","CF","SD1","SD2","USB1","USB2","USB3"
/* _STR_VOLUME_ID option switches string volume ID feature.
/ When _STR_VOLUME_ID is set to 1, also pre-defined strings can be used as drive
/ number in the path name. _VOLUME_STRS defines the drive ID strings for each
/ logical drives. Number of items must be equal to _VOLUMES. Valid characters for
/ the drive ID strings are: A-Z and 0-9. */
#define _MULTI_PARTITION 0
/* This option switches multi-partition feature. By default (0), each logical drive
/ number is bound to the same physical drive number and only an FAT volume found on
/ the physical drive will be mounted. When multi-partition feature is enabled (1),
/ each logical drive number is bound to arbitrary physical drive and partition
/ listed in the VolToPart[]. Also f_fdisk() funciton will be available. */
#define _MIN_SS 512
#define _MAX_SS 4096 //每个扇区的最大字节
/* These options configure the range of sector size to be supported. (512, 1024,
/ 2048 or 4096) Always set both 512 for most systems, all type of memory cards and
/ harddisk. But a larger value may be required for on-board flash memory and some
/ type of optical media. When _MAX_SS is larger than _MIN_SS, FatFs is configured
/ to variable sector size and GET_SECTOR_SIZE command must be implemented to the
/ disk_ioctl() function. */
#define _USE_TRIM 0
/* This option switches ATA-TRIM feature. (0:Disable or 1:Enable)
/ To enable Trim feature, also CTRL_TRIM command should be implemented to the
/ disk_ioctl() function. */
#define _FS_NOFSINFO 0
/* If you need to know correct free space on the FAT32 volume, set bit 0 of this
/ option, and f_getfree() function at first time after volume mount will force
/ a full FAT scan. Bit 1 controls the use of last allocated cluster number.
/
/ bit0=0: Use free cluster count in the FSINFO if available.
/ bit0=1: Do not trust free cluster count in the FSINFO.
/ bit1=0: Use last allocated cluster number in the FSINFO if available.
/ bit1=1: Do not trust last allocated cluster number in the FSINFO.
*/
/*---------------------------------------------------------------------------/
/ System Configurations
/---------------------------------------------------------------------------*/
#define _FS_TINY 0
/* This option switches tiny buffer configuration. (0:Normal or 1:Tiny)
/ At the tiny configuration, size of the file object (FIL) is reduced _MAX_SS
/ bytes. Instead of private sector buffer eliminated from the file object,
/ common sector buffer in the file system object (FATFS) is used for the file
/ data transfer. */
#define _FS_NORTC 0
#define _NORTC_MON 1
#define _NORTC_MDAY 1
#define _NORTC_YEAR 2015
/* The _FS_NORTC option switches timestamp feature. If the system does not have
/ an RTC function or valid timestamp is not needed, set _FS_NORTC to 1 to disable
/ the timestamp feature. All objects modified by FatFs will have a fixed timestamp
/ defined by _NORTC_MON, _NORTC_MDAY and _NORTC_YEAR.
/ When timestamp feature is enabled (_FS_NORTC == 0), get_fattime() function need
/ to be added to the project to read current time form RTC. _NORTC_MON,
/ _NORTC_MDAY and _NORTC_YEAR have no effect.
/ These options have no effect at read-only configuration (_FS_READONLY == 1). */
#define _FS_LOCK 0
/* The _FS_LOCK option switches file lock feature to control duplicated file open
/ and illegal operation to open objects. This option must be 0 when _FS_READONLY
/ is 1.
/
/ 0: Disable file lock feature. To avoid volume corruption, application program
/ should avoid illegal open, remove and rename to the open objects.
/ >0: Enable file lock feature. The value defines how many files/sub-directories
/ can be opened simultaneously under file lock control. Note that the file
/ lock feature is independent of re-entrancy. */
#define _FS_REENTRANT 0
#define _FS_TIMEOUT 1000
#define _SYNC_t HANDLE
/* The _FS_REENTRANT option switches the re-entrancy (thread safe) of the FatFs
/ module itself. Note that regardless of this option, file access to different
/ volume is always re-entrant and volume control functions, f_mount(), f_mkfs()
/ and f_fdisk() function, are always not re-entrant. Only file/directory access
/ to the same volume is under control of this feature.
/
/ 0: Disable re-entrancy. _FS_TIMEOUT and _SYNC_t have no effect.
/ 1: Enable re-entrancy. Also user provided synchronization handlers,
/ ff_req_grant(), ff_rel_grant(), ff_del_syncobj() and ff_cre_syncobj()
/ function, must be added to the project. Samples are available in
/ option/syscall.c.
/
/ The _FS_TIMEOUT defines timeout period in unit of time tick.
/ The _SYNC_t defines O/S dependent sync object type. e.g. HANDLE, ID, OS_EVENT*,
/ SemaphoreHandle_t and etc.. A header file for O/S definitions needs to be
/ included somewhere in the scope of ff.c. */
#define _WORD_ACCESS 0
/* The _WORD_ACCESS option is an only platform dependent option. It defines
/ which access method is used to the word data on the FAT volume.
/
/ 0: Byte-by-byte access. Always compatible with all platforms.
/ 1: Word access. Do not choose this unless under both the following conditions.
/
/ * Address misaligned memory access is always allowed to ALL instructions.
/ * Byte order on the memory is little-endian.
/
/ If it is the case, _WORD_ACCESS can also be set to 1 to reduce code size.
/ Following table shows allowable settings of some type of processors.
/
/ ARM7TDMI 0 *2 ColdFire 0 *1 V850E 0 *2
/ Cortex-M3 0 *3 Z80 0/1 V850ES 0/1
/ Cortex-M0 0 *2 x86 0/1 TLCS-870 0/1
/ AVR 0/1 RX600(LE) 0/1 TLCS-900 0/1
/ AVR32 0 *1 RL78 0 *2 R32C 0 *2
/ PIC18 0/1 SH-2 0 *1 M16C 0/1
/ PIC24 0 *2 H8S 0 *1 MSP430 0 *2
/ PIC32 0 *1 H8/300H 0 *1 8051 0/1
/
/ *1:Big-endian.
/ *2:Unaligned memory access is not supported.
/ *3:Some compilers generate LDM/STM for mem_cpy function.
*/
diskio.c:
/*-----------------------------------------------------------------------*/
/* Low level disk I/O module skeleton for FatFs (C)ChaN, 2014 */
/*-----------------------------------------------------------------------*/
/* If a working storage control module is available, it should be */
/* attached to the FatFs via a glue function rather than modifying it. */
/* This is an example of glue functions to attach various exsisting */
/* storage control modules to the FatFs module with a defined API. */
/*-----------------------------------------------------------------------*/
#include "GuiStar_spi_flash.h"
#include "diskio.h" /* FatFs lower layer API */
#define SPI_FLASH 1
#define CD_CARD 0
/*-----------------------------------------------------------------------*/
/* Get Drive Status */
/*-----------------------------------------------------------------------*/
DSTATUS disk_status (
BYTE pdrv /* Physical drive nmuber to identify the drive */
)
{
DSTATUS stat;
// int result;
switch (pdrv) {
case SPI_FLASH :
if(SPI_FLASH_ReadID()==sFLASH_ID)
{
stat = 0; //状态正常
}
else
{
stat = STA_NOINIT;//状态不正常
}
return stat;
case SD_CARD:
return stat;
}
return STA_NOINIT;
}
/*-----------------------------------------------------------------------*/
/* Inidialize a Drive */
/*-----------------------------------------------------------------------*/
DSTATUS disk_initialize (
BYTE pdrv /* Physical drive nmuber to identify the drive */
)
{
DSTATUS stat;
// int result;
switch (pdrv) {
case SPI_FLASH :
SPI_FLASH_Init();
SPI_Flash_WAKEUP();
stat = disk_status(SPI_FLASH);
return stat;
case SD_CARD:
return stat;
}
return STA_NOINIT;
}
/*-----------------------------------------------------------------------*/
/* Read Sector(s) */
/*-----------------------------------------------------------------------*/
DRESULT disk_read (
BYTE pdrv, /* Physical drive nmuber to identify the drive */
BYTE *buff, /* Data buffer to store read data */
DWORD sector, /* Sector address in LBA */
UINT count /* Number of sectors to read */
)
{
DRESULT res;
// int result;
switch (pdrv) {
case SPI_FLASH :
SPI_FLASH_BufferRead(buff, sector<<12, count<<12);
res = RES_OK;
return res;
case SD_CARD :
return res;
}
return RES_PARERR;
}
/*-----------------------------------------------------------------------*/
/* Write Sector(s) */
/*-----------------------------------------------------------------------*/
#if _USE_WRITE
DRESULT disk_write (
BYTE pdrv, /* Physical drive nmuber to identify the drive */
const BYTE *buff, /* Data to be written */
DWORD sector, /* Sector address in LBA */
UINT count /* Number of sectors to write */
)
{
DRESULT res;
// int result;
switch (pdrv) {
case SPI_FLASH :
SPI_FLASH_SectorErase(sector<<12);//必须要先擦除扇区
SPI_FLASH_BufferWrite((BYTE *)buff, sector<<12, count<<12);
res = RES_OK;
return res;
case SD_CARD:
return res;
}
return RES_PARERR;
}
#endif
/*-----------------------------------------------------------------------*/
/* Miscellaneous Functions */
/*-----------------------------------------------------------------------*/
#if _USE_IOCTL
DRESULT disk_ioctl (
BYTE pdrv, /* Physical drive nmuber (0..) */
BYTE cmd, /* Control code */
void *buff /* Buffer to send/receive control data */
)
{
DRESULT res;
// int result;
switch (pdrv) {
case SPI_FLASH :
switch(cmd)
{
case GET_SECTOR_COUNT://一共有多少个扇区
*(DWORD*)buff=2048;
break;
case GET_SECTOR_SIZE://每个扇区有多大
*(WORD*)buff=4096;
break;
case GET_BLOCK_SIZE://每次擦除的最小单位（单位是扇区)
*(DWORD*)buff=1;
break;
}
res = RES_OK;
return res;
case SD_CARD:
return res;
}
return RES_PARERR;
}
#endif
DWORD get_fattime (void)
{
return 0;
}
这个文件不同的存储介质，差异会很大，但是每个函数实现的功能对于上层函数来说都是相同的，所以在这里说明一下每个函数需要实现的功能：
（1）disk_status ：
在这个函数中，你需要做的是，检测存储介质的状态是否正常，以SPI_FLASH为例，读取一次设备ID，然后，与已知的设备ID对比，如果符合，则返回0，否则返回错误信息
（2）disk_initialize ：
在这个函数中，需要完成设备的初始化，同时调用disk_status获取并返回初始化之后，设备的状态
(3）disk_read 和disk_write：
这两个函数负责完成数据的读取和写入操作，读取自然不必多说，相信在座各位右手就行；写入的话就要注意擦除的问题了
（4）disk_ioctl ：
这个函数需要完成GET_SECTOR_COUNT，GET_SECTOR_SIZE和GET_BLOCK_SIZE等三个必须命令和其他的一些非必须命令，其他的命令如下表：
| CTRL_SYNC |
确保设备已完成挂起的写入过程。如果磁盘 I/O 模块具有回写式缓存，则必须立即将脏缓冲区写回介质。如果在disk_write函数中完成了对介质的每次写入操作，则无需执行此命令。 |
| CTRL_TRIM |
通知设备不再需要由 DWORD 数组 {<启动扇区><端扇区>} 指定的扇区块上的数据，这些数据可能会被擦除。这是与 ATA 设备的修剪相同的命令。当此功能不受支持或不是闪存设备时，无需执行此命令。FatF 不检查结果代码，即使扇区块未被很好地擦除，文件功能也不会受到影响。在删除集群链并f_mkfs函数时调用此命令。在 _USE_TRIM == 1 时是必需的。 |
| CTRL_FORMAT |
在媒体上创建物理格式。如果 buff 不为 null，则它是指向进度通知的回调函数的指针。 |
| CTRL_POWER_IDLE |
将设备置于空闲状态。如果设备通过通用读/写功能进入活动状态，则可能无法设置状态标志中的STA_NOINIT。 |
| CTRL_POWER_OFF |
将设备置于关闭状态。关闭设备的电源，并根据需要取消初始化设备接口。必须设置状态标志中的STA_NOINIT。设备通过disk_initialize功能进入活动状态。 |
| CTRL_LOCK |
锁定介质弹出装置。 |
| CTRL_UNLOCK |
解锁介质弹出机制。 |
| CTRL_EJECT |
弹出介质盒。STA_NOINIT和状态标志中的STA_NODISK是在函数成功后设置的。 |
| MMC_GET_TYPE |
获取卡类型。类型标志位0：MMCv3、位1：SDv1、位2：SDv2+和位3：LBA被存储到由增益所指向的字节变量中。（特定于母板/单点控制的特定命令） |
| MMC_GET_CSD |
将 CSD 寄存器放入由 buff 指向的 16 字节缓冲区中。（特定于母板/单点控制的特定命令） |
| MMC_GET_CID |
将 CID 寄存器放入由 buff 指向的 16 字节缓冲区中。（特定于母板/单点控制的特定命令） |
| MMC_GET_OCR |
将 OCR 寄存器放入由 buff 指向的 4 字节缓冲区中。（特定于母板/单点控制的特定命令） |
| MMC_GET_SDSTAT |
将 SDSTATUS 寄存器放入由抛光块指向的 64 字节缓冲区中。（特定于 SDC 的命令） |
| ATA_GET_REV |
将修订字符串放入由 buff 指向的 16 字节缓冲区中。（针对特定协议的命令） |
| ATA_GET_MODEL |
将模型字符串放入由 buff 指向的 40 字节缓冲区中。（针对特定协议的命令） |
| ATA_GET_SN |
将序列号字符串放入由 buff 指向的 20 字节缓冲区中。（针对特定协议的命令） |
