MSP430 单片机读写SD卡程序（带fat文件系统）

//------------------------------------------------------------------------- /*FAT16.C - LINO TECH Designed by Carter 2008-03-19 */ #include <stdint.h> #include "FAT16.h" #include "sd.h" //------------------------------------------------------------------------ #define SEC_Size 512 #define MBR_Sector 0 //绝对地址 #define FAT_Sector 0 //逻辑地址 //------------------------------------------------------------------------- uint8_t BUFFER[SEC_Size]; uint8_t PB_RelativeSector; uint16_t BPB_BytesPerSec; uint8_t BPB_SecPerClus; uint16_t BPB_RsvdSecCnt; uint8_t BPB_NumFATs; uint16_t BPB_RootEntCnt; uint16_t BPB_TotSec16; uint16_t BPB_FATSz16; //FAT占用的sectors uint32_t BPB_HiddSec; //------------------------------------------------------------------------- uint8_t ReadSector(uint32_t sector, uint8_t* buffer ) { int8 stat; hwInterface sdNow; sdNow.sectorCount = 1; stat = sd_readSector(&sdNow,sector,buffer,512); if(stat==0) { return SD_SUCC; } else { return SD_FAIL; }; } uint8_t WriteSector(uint32_t sector, uint8_t* buffer) { hwInterface sdNow; sdNow.sectorCount = 1; sd_writeSector(&sdNow,sector,buffer); return 0; } uint8_t ReadBlock(uint32_t LBA){ //绝对地址读一个扇区 if(ReadSector(LBA,BUFFER)!=0)return SD_FAIL; return SD_SUCC; } //------------------------------------------------------------------------- uint8_t WriteBlock(uint32_t LBA){ //绝对地址写一个扇区 if(WriteSector(LBA,BUFFER)!=0)return SD_FAIL; return SD_SUCC; } //------------------------------------------------------------------------- uint8_t ReadFatBlock(uint32_t Add){ //逻辑地址读一个扇区 // return ReadBlock(Add+PB_RelativeSector); //for HardDisk return ReadBlock(Add+BPB_HiddSec); } //------------------------------------------------------------------------- uint8_t WriteFatBlock(uint32_t Add){ //逻辑地址写一个扇区 // return WriteBlock(Add+PB_RelativeSector); //for HardDisk return WriteBlock(Add+BPB_HiddSec); } //------------------------------------------------------------------------- void CopyBytes(uint8_t *ps,uint8_t *pd,uint16_t size){ //内存拷贝 for(;size;size--)*pd++=*ps++; } //------------------------------------------------------------------------- uint8_t IsEqual(uint8_t *pa,uint8_t *pb,uint8_t size){ //内存比较 for(;size;size--)if(*pa++!=*pb++)return 0; return 1; } //------------------------------------------------------------------------- void EmptyBytes(uint8_t *pd,uint16_t size){ //内存清空 for(;size;size--)*pd++ =0; } //------------------------------------------------------------------------- uint8_t ReadMBR(void){ //读取MBR数据结构 uint8_t ok; FAT_MBR * MBR=(FAT_MBR*)BUFFER; ok=ReadBlock(MBR_Sector); if(ok==SD_FAIL)return SD_FAIL; if(MBR->MBR_Signature!=0xAA55)return SD_FAIL; //读有效标志 //获取参数 PB_RelativeSector=MBR->MBR_pb[0].PB_RelativeSector;//读逻辑地址与绝对地址的偏移 return SD_SUCC; } //------------------------------------------------------------------------- uint8_t ReadBPB(void){ //读取BPB数据结构 uint8_t ok; FAT_BPB * BPB=(FAT_BPB*)BUFFER; // ok=ReadFatBlock(FAT_Sector); ok=ReadBlock(FAT_Sector); if(ok==SD_FAIL)return SD_FAIL; //获取参数 BPB_BytesPerSec = BPB->BPB_BytesPerSec; BPB_SecPerClus = BPB->BPB_SecPerClus; BPB_RsvdSecCnt = BPB->BPB_RsvdSecCnt; BPB_NumFATs = BPB->BPB_NumFATs; BPB_RootEntCnt = BPB->BPB_RootEntCnt; BPB_TotSec16 = BPB->BPB_TotSec16; BPB_FATSz16 = BPB->BPB_FATSz16; BPB_HiddSec = BPB->BPB_HiddSec; return SD_SUCC; } //------------------------------------------------------------------------- uint32_t DirStartSec(void){ //获取根目录开始扇区号 return BPB_RsvdSecCnt+BPB_NumFATs*BPB_FATSz16; } //------------------------------------------------------------------------- uint16_t GetDirSecCount(void){ //目录项占用的扇区数 return BPB_RootEntCnt*32/BPB_BytesPerSec; } //------------------------------------------------------------------------- uint32_t DataStartSec(void){ //获取数据区开始扇区号 return DirStartSec()+GetDirSecCount(); } //------------------------------------------------------------------------- uint32_t ClusConvLBA(uint16_t ClusID){ //获取一个簇的开始扇区 return DataStartSec()+BPB_SecPerClus*(ClusID-2); } //------------------------------------------------------------------------- uint16_t ReadFAT(uint16_t Index){ //读取文件分配表的指定项 uint16_t *RAM=(uint16_t*)BUFFER; uint32_t SecID; SecID=BPB_RsvdSecCnt+Index/256; ReadFatBlock(SecID); return RAM[Index%256]; } //------------------------------------------------------------------------- void WriteFAT(uint16_t Index,uint16_t Value){ //写文件分配表的指定项 uint16_t *RAM=(uint16_t*)BUFFER; uint32_t SecID; SecID=BPB_RsvdSecCnt+Index/256; ReadFatBlock(SecID); RAM[Index%256]=Value; WriteFatBlock(SecID); } //------------------------------------------------------------------------- uint16_t GetEmptyDIR(void){ //获取根目录中可以使用的一项 uint16_t i,DirSecCut,DirStart,m,ID=0; DirSecCut=GetDirSecCount(); DirStart=DirStartSec(); for(i=0;i<DirSecCut;i++){ ReadFatBlock(DirStart+i); for(m=0;m<16;m++){ if(BUFFER[m*32]==0)return ID; if(BUFFER[m*32]==0xe5)return ID; ID++; } } return ID; } //------------------------------------------------------------------------- //获得和文件名对应的目录 uint8_t GetFileID(uint8_t Name[11],DIR *ID,uint16_t *pIndex){ uint16_t i,DirSecCut,DirStart,m; DirSecCut = GetDirSecCount(); DirStart = DirStartSec(); for(i=0,*pIndex=0;i<DirSecCut;i++){ ReadFatBlock(DirStart+i); for(m=0;m<16;m++){ if(IsEqual(Name,(uint8_t *)&((DIR*)&BUFFER[m*32])->FileName,11)){ *ID = *((DIR*)&BUFFER[m*32]); return 1; //找到对应的目录项,返回1. } (*pIndex)++; } } return 0; //没有找到对应的目录项,返回0. } //------------------------------------------------------------------------- uint16_t GetNextFAT(void){ //获取一个空的FAT项 uint16_t FAT_Count,i; FAT_Count=BPB_FATSz16*256; //FAT表总项数 for(i=0;i<FAT_Count;i++){ if(ReadFAT(i)==0)return i; } return 0; } //------------------------------------------------------------------------- void ReadDIR(uint16_t Index, DIR* Value){ //读取根目录的指定项 uint32_t LBA = DirStartSec()+Index/16; ReadFatBlock(LBA); CopyBytes((uint8_t *)&BUFFER[(Index%16)*32],(uint8_t *)Value,32); } //------------------------------------------------------------------------- void WriteDIR(uint16_t Index, DIR* Value){ //写根目录的指定项 uint32_t LBA = DirStartSec()+Index/16; ReadFatBlock(LBA); CopyBytes((uint8_t *)Value,(uint8_t *)&BUFFER[(Index%16)*32],32); WriteFatBlock(LBA); } //------------------------------------------------------------------------- void CopyFAT(void){ //复制文件分配表,使其和备份一致 uint16_t i; for(i=0;i<BPB_FATSz16;i++){ ReadFatBlock(BPB_RsvdSecCnt+i); WriteFatBlock(BPB_RsvdSecCnt+BPB_FATSz16+i); } } //------------------------------------------------------------------------- uint8_t CreateFile(uint8_t *Name,uint32_t Size){ //创建一个空文件 uint16_t ClusID, ClusNum, ClusNext, i,dirIndex; DIR FileDir; if(GetFileID(Name,&FileDir,&dirIndex)==1)return SD_FAIL; //文件已存在 ClusNum=Size/(BPB_SecPerClus*BPB_BytesPerSec)+1; EmptyBytes((uint8_t *)&FileDir,sizeof(DIR)); CopyBytes(Name,(uint8_t *)&FileDir.FileName,11); FileDir.FilePosit.Size=Size; FileDir.FilePosit.Start=GetNextFAT(); ClusID=FileDir.FilePosit.Start; // for(i=0;i<ClusNum-1;i++){ for(i=0;i<ClusNum;i++){ WriteFAT(ClusID,0xffff); ClusNext=GetNextFAT(); WriteFAT(ClusID,ClusNext); ClusID=ClusNext; } WriteFAT(ClusID, 0xffff); WriteDIR(GetEmptyDIR(),&FileDir); CopyFAT(); return SD_SUCC; } //--------