sd.h

FAT32文件系统的存储机制及其在单片机上的实现,已通过

   //Command for reading CSD Registers
   unsigned char CMD[] = {0x49,0x00,0x00,0x00,0x00,0xFF};
   unsigned char temp;
   temp=MMC_Read_Block(CMD,Buffer,16); //read 16 bytes

   return(temp);
}

//***************************************************************************
//Routine for reading CID Registers from MMC/SD-Card (16Bytes) 
//Return 0 if no Error.
unsigned char Read_CID_MMC(unsigned char *Buffer)
//***************************************************************************
{
   //Command for reading CID Registers
   unsigned char CMD[] = {0x4A,0x00,0x00,0x00,0x00,0xFF}; 
   unsigned char temp;
   temp=MMC_Read_Block(CMD,Buffer,16); //read 16 bytes

   return(temp);
}

//****************************************************************************
//returns the :
// 	size of the card in MB ( ret * 1024^2) == bytes
// 	sector count and multiplier MB are in u08 == C_SIZE / (2^(9-C_SIZE_MULT))
// 	name of the media 
void MMC_get_volume_info(void)
//****************************************************************************
{   unsigned char i;
    unsigned char c_temp[5];
    VOLUME_INFO_TYPE MMC_volume_Info,*vinf;
    send_s("SD CARD Information Read!!");
    vinf=&MMC_volume_Info; //Init the pointoer;
	// read the CSD register
    Read_CSD_MMC(sectorBuffer.dat);
	// get the C_SIZE value. bits [73:62] of data
	// [73:72] == sectorBuffer.data[6] && 0x03
	// [71:64] == sectorBuffer.data[7]
	// [63:62] == sectorBuffer.data[8] && 0xc0
	vinf->sector_count = sectorBuffer.dat[6] & 0x03;
	vinf->sector_count <<= 8;
	vinf->sector_count += sectorBuffer.dat[7];
	vinf->sector_count <<= 2;
	vinf->sector_count += (sectorBuffer.dat[8] & 0xc0) >> 6;
		
	// get the val for C_SIZE_MULT. bits [49:47] of sectorBuffer.data
	// [49:48] == sectorBuffer.data[5] && 0x03
	// [47]    == sectorBuffer.data[4] && 0x80
	vinf->sector_multiply = sectorBuffer.dat[9] & 0x03;
	vinf->sector_multiply <<= 1;
	vinf->sector_multiply += (sectorBuffer.dat[10] & 0x80) >> 7;

	// work out the MBs
	// mega bytes in u08 == C_SIZE / (2^(9-C_SIZE_MULT))
	vinf->size_MB = vinf->sector_count >> (9-vinf->sector_multiply);
	// get the name of the card
	Read_CID_MMC(sectorBuffer.dat);
	vinf->name[0] = sectorBuffer.dat[3];
	vinf->name[1] = sectorBuffer.dat[4];
	vinf->name[2] = sectorBuffer.dat[5];
	vinf->name[3] = sectorBuffer.dat[6];
	vinf->name[4] = sectorBuffer.dat[7];
	vinf->name[5] = 0x00; //end flag
	//----------------------------------------------------------
	/*
	while(1)
	{
	 P1=~(unsigned char)((vinf->size_MB)>>8);
	 delay(50000);
	 delay(50000);
	 delay(50000);
	 delay(50000);
	 delay(50000);
	 P1=~(unsigned char)((vinf->size_MB));
	 delay(50000);
	 delay(50000);
	 delay(50000);
	 delay(50000);
	 delay(50000);
	}*/
    //LCDclrscr();
    //Print Product name on lcd
    i=0;
    send_s("Product Name:");
    //while((vinf->name[i]!=0x00)&&(i<16)) send(vinf->name[i++]);
	send_s(vinf->name);
    //Print Card Size(eg:128MB)
    //gotoxy(1,0);
    send_s("Tot:"); 
    send_s(ftoa(vinf->size_MB,c_temp,0)); 
	send_s("MB ");
    //gotoxy(2,0);
    //writestring("sector_mult:"); writeNumber(vinf->sector_multiply);
    //gotoxy(3,0);
    //writestring("sect_cnt:"); writeNumber(vinf->sector_count);
	
}

//****************************************************************************
//Routine for writing a Block(512Byte) to MMC/SD-Card
//Return 0 if sector writing is completed.
unsigned char MMC_write_sector(unsigned long addr,unsigned char *Buffer)
//****************************************************************************
{  
   unsigned char tmp,retry;
   unsigned int i;
   //Command 24 is a writing blocks command for MMC/SD-Card.
   unsigned char CMD[] = {0x58,0x00,0x00,0x00,0x00,0xFF}; 
   send_s("Write Sector Start!!");
   EA=0; //clear all interrupt.
   addr = addr << 9; //addr = addr * 512
	
   CMD[1] = ((addr & 0xFF000000) >>24 );
   CMD[2] = ((addr & 0x00FF0000) >>16 );
   CMD[3] = ((addr & 0x0000FF00) >>8 );

   //Send Command CMD24 to MMC/SD-Card (Write 1 Block/512 Bytes)
   send_s("Send Command CMD24 to MMC/SD-Card (Write 1 Block/512 Bytes)");
   retry=0;
   do
   {  //Retry 100 times to send command.
      tmp=Write_Command_MMC(CMD);
      retry++;
      if(retry==100) 
      { 
        return(tmp); //send commamd Error!
      }
   }
   while(tmp!=0); 
   
   //Before writing,send 100 clock to MMC/SD-Card
   send_s("Before writing,send 100 clock to MMC/SD-Card");
   for (i=0;i<100;i++)
   {
      Read_Byte_MMC();
   }
	
   //Send Start Byte to MMC/SD-Card
   send_s("Send Start Byte to MMC/SD-Card");
   Write_Byte_MMC(0xFE);	
	
   //Now send real data Bolck (512Bytes) to MMC/SD-Card
   send_s("Now send real data Bolck (512Bytes) to MMC/SD-Card");
   for (i=0;i<512;i++)
   {
      Write_Byte_MMC(*Buffer++); //send 512 bytes to Card
   }

   //CRC-Byte 
   Write_Byte_MMC(0xFF); //Dummy CRC
   Write_Byte_MMC(0xFF); //CRC Code
   
    
   tmp=Read_Byte_MMC();   // read response
   if((tmp & 0x1F)!=0x05) // data block accepted ?
   {
     SPI_CS=1;
     return(WRITE_BLOCK_ERROR); //Error!
   }
   //Wait till MMC/SD-Card is not busy
   send_s("Wait till MMC/SD-Card is not busy");
   while (Read_Byte_MMC()!=0xff){};
	
   //set MMC_Chip_Select to high (MMC/SD-Card Invalid)
   send_s("set MMC_Chip_Select to high (MMC/SD-Card Invalid)");
   SPI_CS=1;
   send_s("Write Sector suc!!");
   return(0);
} 

//***************************************************************************
//Return: [0]-success or something error!
unsigned char MMC_Start_Read_Sector(unsigned long sector)
//***************************************************************************
{  
   unsigned char retry;
   //Command 16 is reading Blocks from MMC/SD-Card
   unsigned char CMD[] = {0x51,0x00,0x00,0x00,0x00,0xFF}; 
   unsigned char temp;
   
   EA=0; //clear all interrupt.
   //Address conversation(logic block address-->byte address)  
   sector = sector << 9; //sector = sector * 512

   CMD[1] = ((sector & 0xFF000000) >>24 );
   CMD[2] = ((sector & 0x00FF0000) >>16 );
   CMD[3] = ((sector & 0x0000FF00) >>8 );
   //Send Command CMD to MMC/SD-Card
   retry=0;
   do
   {  //Retry 100 times to send command.
      temp=Write_Command_MMC(CMD);
      retry++;
      if(retry==100) 
      {
        return(READ_BLOCK_ERROR); //block write Error!
      }
   }
   while(temp!=0); 
   			
   //Read Start Byte form MMC/SD-Card (FEh/Start Byte)
   //Now data is ready,you can read it out.
   while (Read_Byte_MMC() != 0xfe);
   return 0; //Open a sector successfully!
}

//***************************************************************************
void MMC_get_data(unsigned int Bytes,unsigned char *buffer) 
//***************************************************************************
{
   unsigned int j;
   EA=0; //clear all interrupt.
   for (j=0;((j<Bytes) && (readPos<512));j++)
   {	
      *buffer++ = Read_Byte_MMC();
      readPos++; //read a byte,increase read position
   }
   if (readPos==512)  
   {  //CRC-Bytes
      Read_Byte_MMC();//CRC - Byte 
      Read_Byte_MMC();//CRC - Byte
      readPos=0;      //reset sector read offset 
      sectorPos++;    //Need to read next sector
      LBA_Opened=0;   //Set to 1 when a sector is opened.
      //set MMC_Chip_Select to high (MMC/SD-Card invalid)
      SPI_CS=1;;  //MMC disable
   }
}

//***************************************************************************
void MMC_get_data_LBA(unsigned long lba, unsigned int Bytes,unsigned char *buffer)
//***************************************************************************
{ //get data from lba address of MMC/SD-Card
  //If a new sector has to be read then move head
  if (readPos==0) MMC_Start_Read_Sector(lba); 
  MMC_get_data(Bytes,buffer);
}

//***************************************************************************
void MMC_LBA_Close()
//***************************************************************************
{  
   unsigned char temp[1];
   while((readPos!=0x00)|(LBA_Opened==1))
   { //read MMC till readPos==0x00
     MMC_get_data(1, temp); //dummy read,temp is a valid data.
   }  
}

//***************************************************************************
void MMC_GotoSectorOffset(unsigned long LBA,unsigned int offset)
//***************************************************************************
{  
   //Find the offset in the sector
   unsigned char temp[1];
   MMC_LBA_Close(); //close MMC when read a new sector(readPos=0)
   while (readPos<offset) MMC_get_data_LBA(LBA,1,temp); //go to offset  
}