avrfat16.h

移植到mega32上面的fat16代码实现了

/*! \file fat.h \brief FAT16/32 file system driver. */
//*****************************************************************************
//
// File Name	: 'fat.h'
// Title		: FAT16/32 file system driver
// Author		: Pascal Stang
// Date			: 11/07/2000
// Revised		: 12/12/2000
// Version		: 0.3
// Target MCU	: ATmega103 (should work for Atmel AVR Series)
// Editor Tabs	: 4
//
// NOTE: This code is currently below version 1.0, and therefore is considered
// to be lacking in some functionality or documentation, or may not be fully
// tested.  Nonetheless, you can expect most functions to work.
//
///	\ingroup general
/// \defgroup fat FAT16/32 File System Interface (fat.c)
/// \code #include "fat.h" \endcode
/// \par Overview
///		This FAT16/32 interface allows you to detect and mount FAT16/32
///		partitions, browse directories and files, and read file data.
///		The interface is designed to operate with the avrlib IDE/ATA driver.
///		Reading FAT efficiently requires at least 512+ bytes of RAM so this
///		interface may not be suitable for processors with less than 1K of RAM.
///		This interface will properly follow a file's cluster chain so files
///		need not be defragmented.
///
/// \note This code is based in part on work done by Jesper Hansen for his
///		excellent YAMPP MP3 player project.
//
// This code is distributed under the GNU Public License
//		which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************

#ifndef FAT_H
#define FAT_H

#include "global.h"


// Some useful cluster numbers
#define MSDOSFSROOT     0               // cluster 0 means the root dir
#define CLUST_FREE      0               // cluster 0 also means a free cluster
#define MSDOSFSFREE     CLUST_FREE
#define CLUST_FIRST     2               // first legal cluster number
#define CLUST_RSRVD     0xfffffff6      // reserved cluster range
#define CLUST_BAD       0xfffffff7      // a cluster with a defect
#define CLUST_EOFS      0xfffffff8      // start of eof cluster range
#define CLUST_EOFE      0xffffffff      // end of eof cluster range

#define FAT12_MASK      0x00000fff      // mask for 12 bit cluster numbers
#define FAT16_MASK      0x0000ffff      // mask for 16 bit cluster numbers
#define FAT32_MASK      0x0fffffff      // mask for FAT32 cluster numbers


// Partition Type used in the partition record
#define PART_TYPE_UNKNOWN		0x00
#define PART_TYPE_FAT12			0x01
#define PART_TYPE_XENIX			0x02
#define PART_TYPE_DOSFAT16		0x04
#define PART_TYPE_EXTDOS		0x05
#define PART_TYPE_FAT16			0x06
#define PART_TYPE_NTFS			0x07
#define PART_TYPE_FAT32			0x0B
#define PART_TYPE_FAT32LBA		0x0C
#define PART_TYPE_FAT16LBA		0x0E
#define PART_TYPE_EXTDOSLBA		0x0F
#define PART_TYPE_ONTRACK		0x33
#define PART_TYPE_NOVELL		0x40
#define PART_TYPE_PCIX			0x4B
#define PART_TYPE_PHOENIXSAVE	0xA0
#define PART_TYPE_CPM			0xDB
#define PART_TYPE_DBFS			0xE0
#define PART_TYPE_BBT			0xFF

struct partrecord // length 16 bytes
{
	BYTE	prIsActive;					// 0x80 indicates active partition
	BYTE	prStartHead;				// starting head for partition
	WORD	prStartCylSect;				// starting cylinder and sector
	BYTE	prPartType;					// partition type (see above)
	BYTE	prEndHead;					// ending head for this partition
	WORD	prEndCylSect;				// ending cylinder and sector
	DWORD	prStartLBA;					// first LBA sector for this partition
	DWORD	prSize;						// size of this partition (bytes or sectors ?)
};


struct partsector
{
	CHAR	psPartCode[512-64-2];		// pad so struct is 512b
	BYTE	psPart[64];					// four partition records (64 bytes)
	BYTE	psBootSectSig0;				// two signature bytes (2 bytes)
	BYTE	psBootSectSig1;
#define BOOTSIG0        0x55
#define BOOTSIG1        0xaa
};



// Format of a boot sector.  This is the first sector on a DOS floppy disk
// or the first sector of a partition on a hard disk.  But, it is not the
// first sector of a partitioned hard disk.
struct bootsector33 {
	BYTE 	bsJump[3];					// jump inst E9xxxx or EBxx90
	CHAR	bsOemName[8];				// OEM name and version
	CHAR	bsBPB[19];					// BIOS parameter block
	CHAR	bsDriveNumber;				// drive number (0x80)
	CHAR	bsBootCode[479];			// pad so struct is 512b
	BYTE	bsBootSectSig0;				// boot sector signature byte 0x55
	BYTE	bsBootSectSig1;				// boot sector signature byte 0xAA
#define BOOTSIG0        0x55
#define BOOTSIG1        0xaa
};

struct extboot {
	CHAR	exDriveNumber;				// drive number (0x80)
	CHAR	exReserved1;				// reserved
	CHAR	exBootSignature;			// ext. boot signature (0x29)
#define EXBOOTSIG       0x29
	CHAR	exVolumeID[4];				// volume ID number
	CHAR	exVolumeLabel[11];			// volume label
	CHAR	exFileSysType[8];			// fs type (FAT12 or FAT16)
};

struct bootsector50 {
	BYTE	bsJump[3];					// jump inst E9xxxx or EBxx90
	CHAR	bsOemName[8];				// OEM name and version
	CHAR	bsBPB[25];					// BIOS parameter block
	CHAR	bsExt[26];					// Bootsector Extension
	CHAR	bsBootCode[448];			// pad so structure is 512b
	BYTE	bsBootSectSig0;				// boot sector signature byte 0x55
	BYTE	bsBootSectSig1;				// boot sector signature byte 0xAA
#define BOOTSIG0        0x55
#define BOOTSIG1        0xaa
};

struct bootsector710 {
	BYTE	bsJump[3];					// jump inst E9xxxx or EBxx90
	CHAR	bsOEMName[8];				// OEM name and version
	CHAR	bsBPB[53];					// BIOS parameter block
	CHAR	bsExt[26];					// Bootsector Extension
	CHAR	bsBootCode[418];			// pad so structure is 512b
	BYTE	bsBootSectSig2;				// 2 & 3 are only defined for FAT32?
	BYTE	bsBootSectSig3;
	BYTE	bsBootSectSig0;				// boot sector signature byte 0x55
	BYTE	bsBootSectSig1;				// boot sector signature byte 0xAA
#define BOOTSIG0        0x55
#define BOOTSIG1        0xaa
#define BOOTSIG2        0
#define BOOTSIG3        0
};


/***************************************************************/
/***************************************************************/

// BIOS Parameter Block (BPB) for DOS 3.3
struct bpb33 {
        WORD	bpbBytesPerSec; // bytes per sector
        BYTE    bpbSecPerClust;	// sectors per cluster
        WORD	bpbResSectors;	// number of reserved sectors
        BYTE	bpbFATs;		// number of FATs
        WORD	bpbRootDirEnts;	// number of root directory entries
        WORD	bpbSectors;		// total number of sectors
        BYTE	bpbMedia;		// media descriptor
        WORD	bpbFATsecs;     // number of sectors per FAT
        WORD	bpbSecPerTrack; // sectors per track
        WORD	bpbHeads;       // number of heads
        WORD	bpbHiddenSecs;  // number of hidden sectors
};

// BPB for DOS 5.0
// The difference is bpbHiddenSecs is a short for DOS 3.3,
// and bpbHugeSectors is not present in the DOS 3.3 bpb.
struct bpb50 {
        WORD	bpbBytesPerSec; // bytes per sector
        BYTE	bpbSecPerClust; // sectors per cluster
        WORD	bpbResSectors;  // number of reserved sectors
        BYTE	bpbFATs;        // number of FATs
        WORD	bpbRootDirEnts; // number of root directory entries
        WORD	bpbSectors;     // total number of sectors
        BYTE	bpbMedia;       // media descriptor
        WORD	bpbFATsecs;     // number of sectors per FAT
        WORD	bpbSecPerTrack; // sectors per track
        WORD	bpbHeads;       // number of heads
        DWORD	bpbHiddenSecs;  // # of hidden sectors
// 3.3 compat ends here
        DWORD	bpbHugeSectors; // # of sectors if bpbSectors == 0
};

// BPB for DOS 7.10 (FAT32)
// This one has a few extensions to bpb50.
struct bpb710 {
		WORD	bpbBytesPerSec;	// bytes per sector
		BYTE	bpbSecPerClust;	// sectors per cluster
		WORD	bpbResSectors;	// number of reserved sectors
		BYTE	bpbFATs;		// number of FATs
		WORD	bpbRootDirEnts;	// number of root directory entries
		WORD	bpbSectors;		// total number of sectors