fat使用的全局变量.txt

avr MP3 的源程序,包含文件系统,适合初学者

        //Following is file name invalid characters table. Invalid chars are defined by MS. File is 
        //disregarded if one of these characters are found in name. Used in getDirEntry function
        eeprom	byte invalidFileChars[47] = { 
                    0x00, 0x01, 0x02, 0x03, 0x04, 0x06,
                    0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C,
                    0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12,
                    0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
                    0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E,
                    0x1F, 0x22, 0x2A, 0x2B, 0x2C, 0x2E, 
                    0x2F, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E,
                    0x3F, 0x5B, 0x5C, 0x5D, 0x7C };

	//--------------------------------------------------------------------------
        //				FAT Part
        //--------------------------------------------------------------------------
        dword		FirstDataSector;	//First data sector of the partition
        word 		Bytes_Per_Sector;	//Bytes per sector in drive, usually 512 bytes
        byte		Sectors_Per_Cluster;//Sectors per cluster
        word        	Bytes_Per_Cluster;  //bytes of a cluster
        dword  		FirstFATSector;		//First sector of the FAT table
        dword		FirstRootCluster;   //First cluster of Root Directory
        dword   	FirstRootSector;    //First root sector(fat16 or fat12)
        word		rootDirSectors;     //Root directory sectors
        //dword		DriveSize;          //Drive size (free space in drive, used for identification)
        //dword		FirstDirSector;     //First directory sector
        dword		dirStackLBA;		//LBA address of ZIPAMP.SYS file for directory stack
        dword		cfgFileLBA;		    //LBA address of ZIPAMP.CFG file
		
        byte		fileName[FILE_NAME_LENGTH]; //file name, NULL terminated
        byte   		fileExtension[4];	//file extension, 4 byte to make it dword
        dword		FileSize=0;         //File size of the file just read from dir table
        word		currentFileNum; 	//File number from the directory table
        dword		currentCluster;		//Current cluster in file chain.
        dword		firstCluster;		//First cluster of the file just read from dir table.
        byte		subDirLevel=0;		//# of dir level we went down from root directory
		byte		dirString[DIR_STRING_LENGTH];//Dir tree string, used for displaying path on LCD
                                        //position 0 (dirString[0]) stores size of the string.
		byte		FATtype;            //file system type:FAT32=32,FAT16=16.FAT12=12.
		//dword		maxcluster;			//last usable cluster+1
		//byte		dirStack[7];		//used RAM for doing stack
		dword       tableStartCluster;  //unicode.bin file start cluster
		dword       tableSize;          //the size of unicode.bin	    
            
        typedef struct 
        {  //Holds the read offset of each dir entry position in root directiry
            dword   dirLBA;        //sector address of a directory
            word	readPos;       //Offset in sector
            word	fileNum;       //File number
            word    entryCount;    //Root directory Entry count
        } ROOT_OFFSET_TYPE;
        
        ROOT_OFFSET_TYPE    dirReadOffset;     //file root read offset