FAT32.h

//********************************************************
// **** ROUTINES FOR FAT32 IMPLEMATATION OF SD CARD *****
//********************************************************
//Controller: ATmega168 (Clock: 8 Mhz-internal)
//Compiler: AVR-GCC
//Version : 2.1
//Author: CC Dharmani, Chennai (India)
// www.dharmanitech.com
// With some changes by Mujda
//Date: 26 Feb 2009 - updated 13 Sep 2009
//********************************************************

//Link to the Post: http://www.dharmanitech.com/2009/01/sd-card-interfacing-with-atmega8-fat32.html


//**************************************************
// ***** HEADER FILE : FAT32.h ******
//**************************************************
#ifndef _FAT32_H_
#define _FAT32_H_

//Structure to access Master Boot Record for getting info about partioions
struct MBRinfo_Structure{
unsigned char     nothing[446];      //ignore, placed here to fill the gap in the structure
unsigned char     partitionData[64]; //partition records (16x4)
unsigned int      signature;         //0xaa55
};

//Structure to access info of the first partioion of the disk
struct partitionInfo_Structure{
unsigned char     status;                 //0x80 - active partition
unsigned char     headStart;              //starting head
unsigned int      cylSectStart;           //starting cylinder and sector
unsigned char     type;                   //partition type
unsigned char     headEnd;                //ending head of the partition
unsigned int      cylSectEnd;             //ending cylinder and sector
unsigned long     firstSector;            //total sectors between MBR & the first sector of the partition
unsigned long     sectorsTotal;           //size of this partition in sectors
};

//Structure to access boot sector data
struct BS_Structure{
unsigned char jumpBoot[3];      //default: 0x009000EB
unsigned char OEMName[8];
unsigned int  bytesPerSector;   //deafault: 512
unsigned char sectorPerCluster;
unsigned int  reservedSectorCount;
unsigned char numberofFATs;
unsigned int  rootEntryCount;
unsigned int  totalSectors_F16; //must be 0 for FAT32
unsigned char mediaType;
unsigned int  FATsize_F16;      //must be 0 for FAT32
unsigned int  sectorsPerTrack;
unsigned int  numberofHeads;
unsigned long hiddenSectors;
unsigned long totalSectors_F32;
unsigned long FATsize_F32;      //count of sectors occupied by one FAT
unsigned int  extFlags;
unsigned int  FSversion;        //0x0000 (defines version 0.0)
unsigned long rootCluster;      //first cluster of root directory (=2)
unsigned int  FSinfo;           //sector number of FSinfo structure (=1)
unsigned int  BackupBootSector;
unsigned char reserved[12];
unsigned char driveNumber;
unsigned char reserved1;
unsigned char bootSignature;
unsigned long volumeID;
unsigned char volumeLabel[11];   //"NO NAME "
unsigned char fileSystemType[8]; //"FAT32"
unsigned char bootData[420];
unsigned int  bootEndSignature;  //0xaa55
};


//Structure to access FSinfo sector data
struct FSInfo_Structure
{
unsigned long leadSignature;      //0x41615252
unsigned char reserved1[480];
unsigned long structureSignature; //0x61417272
unsigned long freeClusterCount;   //initial: 0xffffffff
unsigned long nextFreeCluster;    //initial: 0xffffffff
unsigned char reserved2[12];
unsigned long trailSignature;     //0xaa550000
};

//Structure to access Directory Entry in the FAT
struct dir_Structure{
unsigned char name[11];
unsigned char attrib;         //file attributes
unsigned char NTreserved;     //always 0
unsigned char timeTenth;      //tenths of seconds, set to 0 here
unsigned int  createTime;     //time file was created
unsigned int  createDate;     //date file was created
unsigned int  lastAccessDate;
unsigned int  firstClusterHI; //higher word of the first cluster number
unsigned int  writeTime;      //time of last write
unsigned int  writeDate;      //date of last write
unsigned int  firstClusterLO; //lower word of the first cluster number
unsigned long fileSize;       //size of file in bytes
};

//Attribute definitions for file/directory
#define ATTR_READ_ONLY     0x01
#define ATTR_HIDDEN        0x02
#define ATTR_SYSTEM        0x04
#define ATTR_VOLUME_ID     0x08
#define ATTR_DIRECTORY     0x10
#define ATTR_ARCHIVE       0x20
#define ATTR_LONG_NAME     0x0f


#define DIR_ENTRY_SIZE     0x32
#define EMPTY              0x00
#define DELETED            0xe5
#define GET         0
#define SET         1
#define READ        0
#define VERIFY      1
#define ADD         0
#define REMOVE      1
#define TOTAL_FREE  1
#define NEXT_FREE   2
#define GET_LIST    0
#define GET_FILE    1
#define DELETE          2
#define EOF         0x0fffffff


//************* external variables *************
extern volatile unsigned char buffer[512];
extern volatile unsigned long startBlock;
extern volatile unsigned long firstDataSector, rootCluster, totalClusters;
extern volatile unsigned int  bytesPerSector, sectorPerCluster, reservedSectorCount;

//global flag to keep track of free cluster count updating in FSinfo sector
unsigned char freeClusterCountUpdated;
unsigned long unusedSectors;

//************* functions *************
unsigned char getBootSectorData (void);

unsigned long getFirstSector(unsigned long clusterNumber);
unsigned long getSetFreeCluster(unsigned char totOrNext, unsigned char get_set, unsigned long FSEntry);
struct dir_Structure* findFiles (unsigned char flag, unsigned char *fileName);
unsigned long getSetNextCluster (unsigned long clusterNumber,unsigned char get_set,unsigned long clusterEntry);
unsigned char readFile (unsigned char flag, unsigned char *fileName);
unsigned char convertFileName (unsigned char *fileName);
void createFile (unsigned char *fileName);
unsigned long searchNextFreeCluster (unsigned long startCluster);
void memoryStatistics (void);
void displayMemory (unsigned long memory);
void deleteFile (unsigned char *fileName);
void freeMemoryUpdate (unsigned char flag, unsigned long size);
void sampleData(unsigned char *line);
void convertToAscii(unsigned char *line, unsigned int start, int val, int places);
void adc_init();

#endif