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Fat32.c
资源名称：51-SD.rar　[点击查看]
上传用户：jcsy2001
上传日期：2013-11-29
资源大小：201k
文件大小：5k
源码类别：

嵌入式/单片机编程

开发平台：

C/C++

Fat32.c：源码内容
  1. #include "common.h"
  2. #include "Fat.h"
  3. #include "Fat32.h"
  4. #include "DEVICE.H"
  5. #include "HAL.H"
  6. ////////////////////////////////////////
  7. extern SYS_INFO_BLOCK xdata DeviceInfo;
  8. extern FILE_INFO xdata ThisFile;
  9. extern unsigned char xdata DBUF[BUFFER_LENGTH];
  10. extern unsigned char xdata FATBUF[512];
  11. ////////////////////////////////////////
  13. unsigned long FirstSectorofCluster32(unsigned long clusterNum)
  14. {
  15. unsigned long temp;
  16. temp=clusterNum-2;
  17. temp=temp*DeviceInfo.BPB_SecPerClus;
  18. temp=temp+DeviceInfo.FirstDataSector;
  19. return temp;
  20. }
  22. unsigned long ThisFatSecNum32(unsigned long clusterNum)
  23. {
  24.    unsigned long temp;
  25.    temp=clusterNum/(DeviceInfo.BPB_BytesPerSec/4);
  26.    temp=temp+DeviceInfo.FatStartSector;
  27.    return temp;
  28. }
  30. unsigned long ThisFatEntOffset32(unsigned long clusterNum)
  31. {
  32. return (clusterNum%(DeviceInfo.BPB_BytesPerSec/4))*4;
  33. }
  35. unsigned long GetNextClusterNum32(unsigned long clusterNum)
  36. {
  37. unsigned long FatSecNum,FatEntOffset;
  39. FatSecNum=ThisFatSecNum32(clusterNum);
  40. FatEntOffset=ThisFatEntOffset32(clusterNum);
  41. if(ThisFile.FatSectorPointer!=FatSecNum)
  42. {
  44. if(!SdReadSector(FatSecNum,1,FATBUF))
  45. return 0xFFFFFFFF;
  46. ThisFile.FatSectorPointer=FatSecNum;
  47. }
  49. ///////////////////////////////////////////////////
  50. clusterNum=LSwapINT32(FATBUF[FatEntOffset],FATBUF[FatEntOffset+1],FATBUF[FatEntOffset+2],FATBUF[FatEntOffset+3]);
  51. return clusterNum;
  52. }
  54. unsigned char GoToPointer32(unsigned long pointer)
  55. {
  57. unsigned int clusterSize;
  59. clusterSize=DeviceInfo.BPB_SecPerClus*DeviceInfo.BPB_BytesPerSec;
  60. ThisFile.ClusterPointer=ThisFile.StartCluster;
  61. while(pointer>clusterSize)
  62. {
  63. pointer-=clusterSize;
  64. ThisFile.ClusterPointer=GetNextClusterNum32(ThisFile.ClusterPointer);
  65. if(ThisFile.ClusterPointer==0xffffffff)
  66. {
  67. return FALSE;
  68. }
  69. }
  70. ThisFile.SectorofCluster=pointer/DeviceInfo.BPB_BytesPerSec;
  71. ThisFile.SectorPointer=FirstSectorofCluster32(ThisFile.ClusterPointer)+ThisFile.SectorofCluster;
  72. ThisFile.OffsetofSector=pointer%DeviceInfo.BPB_BytesPerSec;
  73. ThisFile.FatSectorPointer=0;
  74. return TRUE;
  76. }
  78. unsigned char DeleteClusterLink32(unsigned long clusterNum)
  79. {
  80. unsigned long FatSecNum,FatEntOffset;
  81. unsigned char i;
  82. while((clusterNum>1)&&(clusterNum<DeviceInfo.TotCluster))
  83. {
  84. FatSecNum=ThisFatSecNum32(clusterNum);
  85. FatEntOffset=ThisFatEntOffset32(clusterNum);
  86. if(SdReadSector(FatSecNum,1,DBUF))
  87.        {
  88.          if(clusterNum<DeviceInfo.LastFreeCluster) DeviceInfo.LastFreeCluster=clusterNum; 
  89.  clusterNum=LSwapINT32(DBUF[FatEntOffset],DBUF[FatEntOffset+1],DBUF[FatEntOffset+2],DBUF[FatEntOffset+3]);
  90.        }
  91. else
  92. return FALSE;
  93. DBUF[FatEntOffset]=0x00;DBUF[FatEntOffset+1]=0x00;DBUF[FatEntOffset+2]=0x00;DBUF[FatEntOffset+3]=0x00;
  94. for(i=0;i<DeviceInfo.BPB_NumFATs;i++)
  95. {
  96. DelayMs(5);
  97. if(!SdWriteSector(FatSecNum+i*DeviceInfo.BPB_FATSz32,1,DBUF))
  98. return FALSE;
  99. }
  100. }
  101. return TRUE;
  102. }
  104. unsigned long GetFreeCusterNum32(void)
  105. {
  106. unsigned long xdata clusterNum,i;
  107. unsigned long xdata sectorNum;
  108. unsigned char xdata j;
  109. sectorNum=ThisFatSecNum32(DeviceInfo.LastFreeCluster);
  110.     clusterNum=(sectorNum-DeviceInfo.FatStartSector)*(DeviceInfo.BPB_BytesPerSec/4);
  112. while(sectorNum<DeviceInfo.BPB_FATSz32+DeviceInfo.FatStartSector)
  113. {
  114. if(!SdReadSector(sectorNum,1,DBUF))
  115. return 0x0;
  116. for(i=0;i<DeviceInfo.BPB_BytesPerSec;i=i+4)
  117.    {
  118.     if((DBUF[i]==0)&&(DBUF[i+1]==0)&&(DBUF[i+2]==0)&&(DBUF[i+3]==0))
  119.      {
  120.      DBUF[i]=0xff;DBUF[i+1]=0xff;DBUF[i+2]=0xff;DBUF[i+3]=0xff;
  121. for(j=0;j<DeviceInfo.BPB_NumFATs;j++)
  122. {
  123. DelayMs(5);
  124. if(!SdWriteSector(sectorNum+j*DeviceInfo.BPB_FATSz32,1,DBUF))
  125. return FALSE;
  126. }
  127.                 clusterNum=clusterNum+i/4;
  128.         if((clusterNum-2)<DeviceInfo.TotCluster) 
  129.   {
  130.    if(clusterNum>DeviceInfo.LastFreeCluster) DeviceInfo.LastFreeCluster=clusterNum;
  131.    return clusterNum;
  132.   }
  133.       else return FALSE; 
  134.      }
  135.    }
  136. clusterNum+=DeviceInfo.BPB_BytesPerSec/4;
  137. sectorNum++;
  138. DelayMs(1);
  139. }
  140. return 0x0;
  141. }
  143. unsigned long CreateClusterLink32(unsigned long currentCluster)
  144. {
  145. unsigned long xdata newCluster;
  146. unsigned long xdata FatSecNum,FatEntOffset;
  147. unsigned char xdata i;
  149. newCluster=GetFreeCusterNum32();
  151. FatSecNum=ThisFatSecNum32(currentCluster);
  152. FatEntOffset=ThisFatEntOffset32(currentCluster);
  153. if(SdReadSector(FatSecNum,1,DBUF))
  154. {
  155. DBUF[FatEntOffset]=newCluster;
  156. DBUF[FatEntOffset+1]=newCluster>>8;
  157. DBUF[FatEntOffset+2]=newCluster>>16;
  158. DBUF[FatEntOffset+3]=newCluster>>24;
  159. for(i=0;i<DeviceInfo.BPB_NumFATs;i++)
  160. {
  161. DelayMs(5);
  162. if(!SdWriteSector(FatSecNum+i*DeviceInfo.BPB_FATSz32,1,DBUF))
  163. return FALSE;
  164. }
  165. }
  166. else
  167. return 0x00;
  169. return newCluster;
  170. }