fat32.h

fat32文件系统源代码

#include <sd.h>
#include <ctype.h>

/*
     振南 简易FAT32文件系统，不断完善中
	  V1.01
	  振南电子网  www.znmcu.cn
	  振南电子论坛 bbs.znmcu.cn
*/

sbit DATA  =P2^5;
sbit CLK   =P2^4;
sbit XCS   =P2^3 ;
sbit XRESET=P2^2 ;
sbit DREQ  =P2^1 ;
sbit XDCS  =P2^0 ;

#define VOL_VALUE 0x0000

/*
 分区记录结构如下
*/
struct PartRecord
{
 unsigned char Active;         //0x80表示此分区有效
 unsigned char StartHead;      //分区的开始头
 unsigned char StartCylSect[2];//开始柱面与扇区
 unsigned char PartType;       //分区类型
 unsigned char EndHead;        //分区的结束头
 unsigned char EndCylSect[2];  //结束柱面与扇区
 unsigned char StartLBA[4];    //分区的第一个扇区
 unsigned char Size[4];        //分区的大小 
};

/*
 分区扇区（绝对0扇区）定义如下
*/
struct PartSector
{
 unsigned char PartCode[446]; //MBR的引导程序
 struct PartRecord Part[4];      //4个分区记录
 unsigned char BootSectSig0;
 unsigned char BootSectSig1;
};

struct FAT32_FAT_Item
{
 unsigned char Item[4];
};

struct FAT32_FAT
{
 struct FAT32_FAT_Item Items[128];
};

/*
 FAT32中对BPB的定义如下  一共占用90个字节
*/
struct FAT32_BPB
{
 unsigned char BS_jmpBoot[3];     //跳转指令            offset: 0
 unsigned char BS_OEMName[8];     //                    offset: 3
 unsigned char BPB_BytesPerSec[2];//每扇区字节数        offset:11
 unsigned char BPB_SecPerClus[1]; //每簇扇区数          offset:13
 unsigned char BPB_RsvdSecCnt[2]; //保留扇区数目        offset:14
 unsigned char BPB_NumFATs[1];    //此卷中FAT表数       offset:16
 unsigned char BPB_RootEntCnt[2]; //FAT32为0            offset:17
 unsigned char BPB_TotSec16[2];   //FAT32为0            offset:19
 unsigned char BPB_Media[1];      //存储介质            offset:21
 unsigned char BPB_FATSz16[2];    //FAT32为0            offset:22
 unsigned char BPB_SecPerTrk[2];  //磁道扇区数          offset:24
 unsigned char BPB_NumHeads[2];   //磁头数              offset:26
 unsigned char BPB_HiddSec[4];    //FAT区前隐扇区数     offset:28
 unsigned char BPB_TotSec32[4];   //该卷总扇区数        offset:32

 unsigned char BPB_FATSz32[4];    //一个FAT表扇区数     offset:36
 unsigned char BPB_ExtFlags[2];   //FAT32特有           offset:40
 unsigned char BPB_FSVer[2];      //FAT32特有           offset:42
 unsigned char BPB_RootClus[4];   //根目录簇号          offset:44
 unsigned char FSInfo[2];         //保留扇区FSINFO扇区数offset:48
 unsigned char BPB_BkBootSec[2];  //通常为6             offset:50
 unsigned char BPB_Reserved[12];  //扩展用              offset:52
 unsigned char BS_DrvNum[1];      //                    offset:64
 unsigned char BS_Reserved1[1];   //                    offset:65
 unsigned char BS_BootSig[1];     //                    offset:66
 unsigned char BS_VolID[4];       //                    offset:67
 unsigned char BS_FilSysType[11]; //	                offset:71
 unsigned char BS_FilSysType1[8]; //"FAT32    "         offset:82
};

// Structure of a dos directory entry.
struct direntry 
{
 unsigned char deName[8];       // filename, blank filled
 unsigned char deExtension[3]; 	// extension, blank filled
 unsigned char deAttributes;   	// file attributes
 unsigned char deLowerCase;    	// NT VFAT lower case flags  (set to zero)
 unsigned char deCHundredth;   	// hundredth of seconds in CTime
 unsigned char deCTime[2];     	// create time
 unsigned char deCDate[2];     	// create date
 unsigned char deADate[2];     	// access date
 unsigned char deHighClust[2];     // high unsigned chars of cluster number
 unsigned char deMTime[2];     	// last update time
 unsigned char deMDate[2];     	// last update date
 unsigned char deLowCluster[2]; 	// starting cluster of file
 unsigned char deFileSize[4];      // size of file in unsigned chars
};

// Stuctures
struct FileInfoStruct
{
 unsigned char  FileName[12];
 unsigned long  FileStartCluster;			//< file starting cluster for last file accessed
 unsigned long  FileCurCluster;
 unsigned long  FileNextCluster;
 unsigned long  FileSize;					//< file size for last file accessed
 unsigned char  FileAttr;					//< file attr for last file accessed
 unsigned short FileCreateTime;			//< file creation time for last file accessed
 unsigned short FileCreateDate;			//< file creation date for last file accessed
 unsigned short FileMTime;
 unsigned short FileMDate;
 unsigned long  FileSector;				    //<file record place
 unsigned long   FileOffset;				    //<file record offset
};

/*
  FAT32初始化时初始参数装入如下结构体中
*/
struct FAT32_Init_Arg
{
 unsigned char BPB_Sector_No;   //BPB所在扇区号
 unsigned long Total_Size;            //磁盘的总容量
 unsigned long FirstDirClust;       //根目录的开始簇
 unsigned long FirstDataSector;	 //文件数据开始扇区号
 unsigned int  BytesPerSector;	 //每个扇区的字节数
 unsigned int  FATsectors;            //FAT表所占扇区数
 unsigned int  SectorsPerClust;	 //每簇的扇区数
 unsigned long FirstFATSector;	 //第一个FAT表所在扇区
 unsigned long FirstDirSector;	 //第一个目录所在扇区
 unsigned long RootDirSectors;	 //根目录所占扇区数
 unsigned long RootDirCount;	 //根目录下的目录与文件数
};

//#define FIND_BPB_UP_RANGE 2000  //BPB不一定在0扇区，对0～FINE_BPB_UP_RANGE扇区进行扫描


unsigned char xdata FAT32_Buffer[512]; //扇区数据读写缓冲区
struct FAT32_Init_Arg Init_Arg;	       //初始化参数结构体实体
struct FileInfoStruct FileInfo;        //文件信息结构体实体

unsigned char * FAT32_ReadSector(unsigned long LBA,unsigned char *buf) //FAT32中读取扇区的函数
{
 MMC_get_data_LBA(LBA,512,buf);
 return buf;
}

unsigned char FAT32_WriteSector(unsigned long LBA,unsigned char *buf)//FAT32中写扇区的函数
{
 return MMC_write_sector(LBA,buf);
}

unsigned long lb2bb(unsigned char *dat,unsigned char len) //小端转为大端
{
 unsigned long temp=0;
 unsigned long fact=1;
 unsigned char i=0;
 for(i=0;i<len;i++)
 {
  temp+=dat[i]*fact;
  fact*=256;
 }
 return temp;
}

unsigned long  FAT32_FindBPB()  //寻找BPB所在的扇区号
{
 if(FAT32_Buffer[0]!=0xeb)
 return lb2bb(((((struct PartSector *)(FAT32_Buffer))->Part[0]).StartLBA),4);
 else
 return 0;
}

unsigned long FAT32_Get_Total_Size() //存储器的总容量，单位为M
{
 FAT32_ReadSector(Init_Arg.BPB_Sector_No,FAT32_Buffer);
 return ((float)(lb2bb((((struct FAT32_BPB *)(FAT32_Buffer))->BPB_TotSec32),4)))*0.0004883;
}

void FAT32_Init(struct FAT32_Init_Arg *arg)
{
 struct FAT32_BPB *bpb=(struct FAT32_BPB *)(FAT32_Buffer);             //将数据缓冲区指针转为struct FAT32_BPB 型指针
 arg->BPB_Sector_No   =FAT32_FindBPB();                                             //FAT32_FindBPB()可以返回BPB所在的扇区号
 arg->Total_Size      =FAT32_Get_Total_Size();                                        //FAT32_Get_Total_Size()可以返回磁盘的总容量，单位是兆
 arg->FATsectors      =lb2bb((bpb->BPB_FATSz32)    ,4);                       //装入FAT表占用的扇区数到FATsectors中
 arg->FirstDirClust   =lb2bb((bpb->BPB_RootClus)   ,4);                        //装入根目录簇号到FirstDirClust中
 arg->BytesPerSector  =lb2bb((bpb->BPB_BytesPerSec),2);                   //装入每扇区字节数到BytesPerSector中
 arg->SectorsPerClust =lb2bb((bpb->BPB_SecPerClus) ,1);                   //装入每簇扇区数到SectorsPerClust 中
 arg->FirstFATSector  =lb2bb((bpb->BPB_RsvdSecCnt) ,2)+arg->BPB_Sector_No;//装入第一个FAT表扇区号到FirstFATSector 中
 arg->RootDirCount    =lb2bb((bpb->BPB_RootEntCnt) ,2);                   //装入根目录项数到RootDirCount中
 arg->RootDirSectors  =(arg->RootDirCount)*32>>9;                           //装入根目录占用的扇区数到RootDirSectors中
 arg->FirstDirSector  =(arg->FirstFATSector)+(bpb->BPB_NumFATs[0])*(arg->FATsectors); //装入第一个目录扇区到FirstDirSector中
 arg->FirstDataSector =(arg->FirstDirSector)+(arg->RootDirSectors); //装入第一个数据扇区到FirstDataSector中
}

void FAT32_EnterRootDir()
{
 unsigned long iRootDirSector;
 unsigned long iDir;
 struct direntry *pDir;
 for(iRootDirSector=(Init_Arg.FirstDirSector);iRootDirSector<(Init_Arg.FirstDirSector)+(Init_Arg.SectorsPerClust);iRootDirSector++)
 {
  FAT32_ReadSector(iRootDirSector,FAT32_Buffer);
  for(iDir=0;iDir<Init_Arg.BytesPerSector;iDir+=sizeof(struct direntry))
  {
   pDir=((struct direntry *)(FAT32_Buffer+iDir));
   if((pDir->deName)[0]!=0x00 /*无效目录项*/ && (pDir->deName)[0]!=0xe5 /*无效目录项*/ && (pDir->deName)[0]!=0x0f /*无效属性*/)
   {
    Printf_File_Name(pDir->deName);
   }
  }
 }
}

void FAT32_CopyName(unsigned char *Dname,unsigned char *filename)
{
 unsigned char i=0;
 for(;i<11;i++)
 {
  Dname[i]=filename[i];
 }
 Dname[i]=0;
}

unsigned long FAT32_EnterDir(char *path)
{
 unsigned long iDirSector;
 unsigned long iCurSector=Init_Arg.FirstDirSector;
 unsigned long iDir;
 struct direntry *pDir;
 unsigned char DirName[12];
 unsigned char depth=0,i=0;
 while(path[i]!=0)
 {
  if(path[i]=='\\')
  { 
   depth++;
  }
  i++;
 }
 if(depth==1)