rotek
/
module_universal_io


			
				
					
						
						
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<h2>FATFS</h2>
<p>The <tt>FATFS</tt> structure (file system object) holds dynamic work area of individual logical drives. It is given by application program and registerd/unregisterd to the FatFs module with <tt>f_mount</tt> function. Initialization is done on first API call after <tt>f_mount</tt> function or media change. Application program must not modify any member in this structure, or any data on the FAT volume can be collapsed.</p>
<pre>
<span class="k">typedef</span> <span class="k">struct</span> {
    BYTE    fs_type;      <span class="c">/* FAT sub-type (0:Not mounted, FS_FAT12/FS_FAT16/FS_FAT32) */</span>
    BYTE    drv;          <span class="c">/* Physical drive number */</span>
    BYTE    csize;        <span class="c">/* Sectors per cluster (1,2,4,...,128) */</span>
    BYTE    n_fats;       <span class="c">/* Number of FAT copies (1,2) */</span>
    BYTE    wflag;        <span class="c">/* win[] flag (b0:win[] is dirty) */</span>
    BYTE    fsi_flag;     <span class="c">/* FSINFO flags (b7:Disabled, b0:Dirty) */</span>
    WORD    id;           <span class="c">/* File system mount ID */</span>
    WORD    n_rootdir;    <span class="c">/* Number of root directory entries (FAT12/16) */</span>
<span class="k">#if</span> _MAX_SS != _MIN_SS
    WORD    ssize;        <span class="c">/* Sector size (512,1024,2048 or 4096) */</span>
<span class="k">#endif</span>
<span class="k">#if</span> _FS_REENTRANT
    _SYNC_t sobj;         <span class="c">/* Identifier of sync object */</span>
<span class="k">#endif</span>
<span class="k">#if</span> !_FS_READONLY
    DWORD   last_clust;   <span class="c">/* FSINFO: Last allocated cluster (0xFFFFFFFF if invalid) */</span>
    DWORD   free_clust;   <span class="c">/* FSINFO: Number of free clusters (0xFFFFFFFF if invalid) */</span>
<span class="k">#endif</span>
<span class="k">#if</span> _FS_RPATH
    DWORD   cdir;         <span class="c">/* Cluster number of current directory (0:root) */</span>
<span class="k">#endif</span>
    DWORD   n_fatent;     <span class="c">/* Number of FAT entries (Number of clusters + 2) */</span>
    DWORD   fsize;        <span class="c">/* Sectors per FAT */</span>
    DWORD   volbase;      <span class="c">/* Volume base LBA */</span>
    DWORD   fatbase;      <span class="c">/* FAT base LBA */</span>
    DWORD   dirbase;      <span class="c">/* Root directory base (LBA|Cluster) */</span>
    DWORD   database;     <span class="c">/* Data base LBA */</span>
    DWORD   winsect;      <span class="c">/* Sector LBA appearing in the win[] */</span>
    BYTE    win[_MAX_SS]; <span class="c">/* Disk access window for directory, FAT (and file data at tiny cfg) */</span>
} FATFS;
</pre>
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