fat.h

PIC MMC and FAT Sample code

// Boot Sector Configuration
//	=================================================================================================
//			Entry						Position /	Description									Remarks
//										Length
//	=================================================================================================
#DEFINE	bsJumpCommand		//	0x00 / 3		Jump Command								0xEB 0xXX 0x90
#DEFINE	bsOEMName			//	0x03 / 8		OEM Name										XXX
#DEFINE	bsBytesPerSec		//	0x0B / 2		Bytes/Sector								512
#DEFINE	bsSecPerCluster	//	0x0D / 1		Sectors/Cluster							XXX (range: 1-64)
#DEFINE	bsReservedSec		//	0x0E / 2		Reserved Sectors							1
#DEFINE	bsNoOfFATs			//	0x10 / 1		Number of FATs								2
#DEFINE	bsNoRootDirs		//	0x11 / 2		Number of Root Directory Entries		512
#DEFINE	bsNoSecOnMedia		//	0x13 / 2		Number of Sectors on Media				XXX (Depends on card capacity. If the media has more than 65535 sectors, this field is zero and the 'number of total sectos' is set.)
#DEFINE	bsMediaDescriptor	//	0x15 / 1		Media Descriptor							0xF8 (Harddisk)
#DEFINE	bsSecPerFAT			//	0x16 / 2		Sectors/FAT									XXX
#DEFINE	bsSecPerTrack		//	0x18 / 2		Sectors/Track								32 (No Meaning)
#DEFINE	bsNoOfHeads			//	0x1A / 2		Number of Heads							2 (No Meaning)
#DEFINE	bsNoHiddenSec		//	0x1C / 4		Number of Hidden Sectors				0
#DEFINE	bsNoTotalSec		//	0x20 / 4		Number of Total Sectors					XXX (Depends on Capacity)
#DEFINE	bsDriveNo			//	0x24 / 1		Drive Number								0x80
//#DEFINE	bsReserved		//	0x25 / 1		Reserved										0
#DEFINE	bsExtdBootSign		//	0x26 / 1		Extended Boot Signature					0x29
#DEFINE	bsVolIDSN			//	0x27 / 4		Volume ID or Serial Number				XXX
#DEFINE	bsVolLabel			//	0x2B / 11	Volume Label								XXX (ASCII characters padded with blanks if less than 11 characters)
#DEFINE	bsFileSysType		//	0x36 / 8		File System Type							XXX (ASCII characters identifying the file system type FAT12 or FAT16)
#DEFINE	bsLoadProgCode		//	0x3E / 448	Load Program Code							XXX
#DEFINE	bsSignature			//	0x01FE / 2	Signature									0x55 0xAA

// Partition Table
//	=================================================================================================
//			Entry						Position /	Description									Remarks
//										Length
//	=================================================================================================
#DEFINE	ptCRC					//	0x00 / 446	Consistency Routine Check
#DEFINE	ptEntry1				//	0x01BE / 16	Partition Table Entry					
#DEFINE	ptEntry2				//	0x01CE / 16	Partition Table Entry					
#DEFINE	ptEntry3				//	0x01DE / 16	Partition Table Entry					
#DEFINE	ptEntry4				//	0x01EE / 16	Partition Table Entry					
#DEFINE	ptSignature			//	0x01FE / 1	Signature									0x55 0xAA

// Partition Entry Description
//	====================================================================================================================================================
//			Entry						Position /	Description												Remarks
//										Length
//	===============================================================================================================================================
#DEFINE	peBootDesc				//	0x00 / 1		Boot Descriptor						0x00 (Non-Bootable Device)
										//																0x80 (Bootable Device)
#DEFINE	peFirstPartitionSec	//	0x01 / 3		First Partition Sector				Address of Frist sector.
#DEFINE	peFileSysDesc			//	0x04 / 1		File System Descriptor				0x00 (Empty)
										//																0x01 (DOS 12-bit FAT < 16 MB)
										//																0x04 (DOS 16-bit FAT < 32 MB)
										//																0x05 (Extended DOS)
										//																0x06 (DOS 16-bit FAT >= 32 MB)
#DEFINE	peLastPartitionSec	//	0x05 / 3		Last Partition Sector				Address of Last Sector.
#DEFINE	peFirstSecPos			//	0x08 / 4		First Sector Relative to 			Number of First Sector (Linear Address)
										//					Beginning of Device	
#DEFINE	peNoSecinPartition	//	0x0C / 4		Number of Sectors in Partition	Between one and Maximum Number of Sectors on Device

// Partition Entry Addresses
#DEFINE	PARTITION1	0x01BE
#DEFINE	PARTITION2	0x01CE
#DEFINE	PARTITION3	0x01DE
#DEFINE	PARTITION4	0x01EE

// FAT Codes


// Global Variables
DWORD	peStart;			// Absolute byte address of the first sector of Partition 1.
DWORD fatStart;		// Absolute byte address of the first sector of the FAT of Partition 1.
DWORD rootDirStart;	// Absolute byte address of the first sector of the Root Directory of Partition 1.
DWORD dataSecStart;	// Absolute byte address of the first sector of the first data cluster of Partition 1 (ie N=2)
BYTE fatSecPerClus;	// Stores the size of a cluster in number of sectors.