FATFS

The FATFS structure holds dynamic work area of individual logical drives. It is given by application program and registerd/unregisterd to the FatFs module with f_mount function. Following members are in standard configuration. There is no member that can be changed from the application program.

typedef struct _FATFS_ {
    BYTE    fs_type;    /* FAT sub type */
    BYTE    drive;      /* Physical drive number */
    BYTE    csize;      /* Number of sectors per cluster */
    BYTE    n_fats;     /* Number of FAT copies */
    BYTE    wflag;      /* win[] dirty flag (1:must be written back) */
    BYTE    fsi_flag;   /* fsinfo dirty flag (1:must be written back) */
    WORD    id;         /* File system mount ID */
    WORD    n_rootdir;  /* Number of root directory entries (0 on FAT32) */
#if _FS_REENTRANT
    _SYNC_t sobj;       /* Identifier of sync object */
#endif
#if _MAX_SS != 512
    WORD    s_size;     /* Sector size */
#endif
#if !_FS_READONLY
    DWORD   last_clust; /* Last allocated cluster */
    DWORD   free_clust; /* Number of free clusters */
    DWORD   fsi_sector; /* fsinfo sector */
#endif
#if _FS_RPATH
    DWORD   cdir;       /* Current directory (0:root)*/
#endif
    DWORD   sects_fat;  /* Sectors per fat */
    DWORD   max_clust;  /* Maximum cluster# + 1. Number of clusters is max_clust - 2 */
    DWORD   fatbase;    /* FAT start sector */
    DWORD   dirbase;    /* Root directory start sector (Cluster# on FAT32) */
    DWORD   database;   /* Data start sector */
    DWORD   winsect;    /* Current sector appearing in the win[] */
    BYTE    win[_MAX_SS];/* Disk access window for Directory/FAT */
} FATFS;