?? b03b7a6e710e001c1231859690fa092d

?? This designs uses a Nios II system to demonstrate how to read from the SD card. The software reads W
字號:
#ifndef   __SD_Card_H__
#define   __SD_Card_H__
//-------------------------------------------------------------------------
//  SD Card Set I/O Direction
#define SD_CMD_IN   IOWR(SD_CMD_BASE, 1, 0)
#define SD_CMD_OUT  IOWR(SD_CMD_BASE, 1, 1)
#define SD_DAT_IN   IOWR(SD_DAT_BASE, 1, 0)
#define SD_DAT_OUT  IOWR(SD_DAT_BASE, 1, 1)
//  SD Card Output High/Low
#define SD_CMD_LOW  IOWR(SD_CMD_BASE, 0, 0)
#define SD_CMD_HIGH IOWR(SD_CMD_BASE, 0, 1)
#define SD_DAT_LOW  IOWR(SD_DAT_BASE, 0, 0)
#define SD_DAT_HIGH IOWR(SD_DAT_BASE, 0, 1)
#define SD_CLK_LOW  IOWR(SD_CLK_BASE, 0, 0)
#define SD_CLK_HIGH IOWR(SD_CLK_BASE, 0, 1)
//  SD Card Input Read
#define SD_TEST_CMD IORD(SD_CMD_BASE, 0)
#define SD_TEST_DAT IORD(SD_DAT_BASE, 0)
//-------------------------------------------------------------------------
#define BYTE    unsigned char
#define UINT16  unsigned int
#define UINT32  unsigned long

//-------------------------------------------------------------------------
void Ncr(void);
void Ncc(void);
BYTE response_R(BYTE);
BYTE send_cmd(BYTE *);
BYTE SD_read_lba(BYTE *,UINT32,UINT32);
BYTE SD_write_lba(BYTE *,UINT32,UINT32);  //寫lba
BYTE SD_card_init(void);
//-------------------------------------------------------------------------
BYTE read_status;
BYTE write_status;   //寫操作的狀態(tài)
BYTE response_buffer[20];
BYTE RCA[2];
BYTE cmd_buffer[5];
const BYTE cmd0[5]   = {0x40,0x00,0x00,0x00,0x00};
const BYTE cmd55[5]  = {0x77,0x00,0x00,0x00,0x00};
const BYTE cmd2[5]   = {0x42,0x00,0x00,0x00,0x00};
const BYTE cmd3[5]   = {0x43,0x00,0x00,0x00,0x00};
const BYTE cmd7[5]   = {0x47,0x00,0x00,0x00,0x00};
const BYTE cmd9[5]   = {0x49,0x00,0x00,0x00,0x00};
const BYTE cmd13[5]   = {0x4D,0x00,0x00,0x00,0x00};
const BYTE cmd16[5]  = {0x50,0x00,0x00,0x02,0x00};
const BYTE cmd17[5]  = {0x51,0x00,0x00,0x00,0x00};
const BYTE cmd24[5]  = {0x58,0x00,0x00,0x00,0x00};  
const BYTE acmd6[5]  = {0x46,0x00,0x00,0x00,0x02};
const BYTE acmd41[5] = {0x69,0x0f,0xf0,0x00,0x00};
const BYTE acmd51[5] = {0x73,0x00,0x00,0x00,0x00};
//-------------------------------------------------------------------------
void Ncr(void)
{
  SD_CMD_IN;
  SD_CLK_LOW;
  SD_CLK_HIGH;
  SD_CLK_LOW;
  SD_CLK_HIGH;
} 
//-------------------------------------------------------------------------
void Ncc(void)
{
  int i;
  for(i=0;i<8;i++)
  {
    SD_CLK_LOW;
    SD_CLK_HIGH;
  }
}
//-------------------------------------------------------------------------
BYTE SD_card_init(void)
{
    BYTE x,y;
    SD_CMD_OUT;
    SD_DAT_IN;
    SD_CLK_HIGH;
    SD_CMD_HIGH;
    SD_DAT_LOW;
    read_status=0;
    for(x=0;x<40;x++)
    Ncr();
    for(x=0;x<5;x++)
    cmd_buffer[x]=cmd0[x];
    y = send_cmd(cmd_buffer);
    do
    {
      for(x=0;x<40;x++);
      Ncc();
      for(x=0;x<5;x++)
      cmd_buffer[x]=cmd55[x];
      y = send_cmd(cmd_buffer);
      Ncr();
      if(response_R(1)>1) //response too long or crc error
      return 1;
      Ncc();
      for(x=0;x<5;x++)
      cmd_buffer[x]=acmd41[x];
      y = send_cmd(cmd_buffer);
      Ncr();      
    } while(response_R(3)==1);
    Ncc();
    for(x=0;x<5;x++)
    cmd_buffer[x]=cmd2[x];
    y = send_cmd(cmd_buffer);
    Ncr();
    if(response_R(2)>1)
    return 1;
    Ncc();
    for(x=0;x<5;x++)
    cmd_buffer[x]=cmd3[x];
    y = send_cmd(cmd_buffer);
    Ncr();
    if(response_R(6)>1)
    return 1;         
    RCA[0]=response_buffer[1];
    RCA[1]=response_buffer[2];
    Ncc();
    for(x=0;x<5;x++)
    cmd_buffer[x]=cmd9[x];
    cmd_buffer[1] = RCA[0];
    cmd_buffer[2] = RCA[1];  
    y = send_cmd(cmd_buffer);
    Ncr();
    if(response_R(2)>1)
    return 1; 
    Ncc();
    for(x=0;x<5;x++)
    cmd_buffer[x]=cmd7[x];
    cmd_buffer[1] = RCA[0];
    cmd_buffer[2] = RCA[1];
    y = send_cmd(cmd_buffer);
    Ncr();
    if(response_R(1)>1)
    return 1; 
    Ncc();
    for(x=0;x<5;x++)
    cmd_buffer[x]=cmd16[x];
    y = send_cmd(cmd_buffer);  
    Ncr();
    if(response_R(1)>1)
    return 1;
    read_status =1; //sd card ready
    return 0;
}
//-------------------------------------------------------------------------
BYTE SD_read_lba(BYTE *buff,UINT32 lba,UINT32 seccnt)
{
  BYTE c=0;
  UINT32  i,j;
  lba+=101; 
  SD_CMD_OUT;  
  SD_DAT_IN;   
   
  for(j=0;j<seccnt;j++)
  {
    {      
       Ncc();         
      cmd_buffer[0] = cmd17[0];
      cmd_buffer[1] = (lba>>15)&0xff; 
      cmd_buffer[2] = (lba>>7)&0xff;
      cmd_buffer[3] = (lba<<1)&0xff;
      cmd_buffer[4] = 0;
      lba++;
      send_cmd(cmd_buffer); 
      Ncr();
    } 
  while(1)
    {
      SD_CLK_LOW;
      SD_CLK_HIGH;
      if(!(SD_TEST_DAT))
      break;
    }
    
    for(i=0;i<512;i++)
    {
      BYTE j;
      for(j=0;j<8;j++)
      {
        SD_CLK_LOW;
        SD_CLK_HIGH;
        c <<= 1; 
        if(SD_TEST_DAT)
        c |= 0x01;
      } 
      *buff=c;
      buff++;
    } 
    for(i=0; i<16; i++)
    {
        SD_CLK_LOW;
        SD_CLK_HIGH;
    }
  }
  read_status = 1;  //SD data next in
  return 0;
}
//-------------------------------------------------------------------------
BYTE response_R(BYTE s)
{
  BYTE a=0,b=0,c=0,r=0,crc=0;
  BYTE i,j=6,k;
  while(1)
  {
    SD_CLK_LOW;
    SD_CLK_HIGH;
    if(!(SD_TEST_CMD))
    break;
    if(crc++ >100)
    return 2;
  } 
  crc =0;
  if(s == 2)
  j = 17;

  for(k=0; k<j; k++)
  {
    c = 0;
    if(k > 0)                      //for crc culcar
    b = response_buffer[k-1];    
    for(i=0; i<8; i++)
    {
      SD_CLK_LOW;
      if(a > 0)
      c <<= 1; 
      else
      i++; 
      a++; 
      SD_CLK_HIGH;
      if(SD_TEST_CMD)
      c |= 0x01;
      if(k > 0)
      {
        crc <<= 1;
        if((crc ^ b) & 0x80)
        crc ^= 0x09;
        b <<= 1;
        crc &= 0x7f;
      }
    }
    if(s==3)
    { 
      if( k==1 &&(!(c&0x80)))
      r=1;
    }
    response_buffer[k] = c;
  }
  if(s==1 || s==6)
  {
    if(c != ((crc<<1)+1))
    r=2;
  } 
  return r; 
}
//-------------------------SD_write_lba----------------------------------------
BYTE SD_write_lba(BYTE *buff,UINT32 lba,UINT32 seccnt)  
{    
  /*UINT16 const CRCTable[256]={0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
              0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef,
              0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6,
              0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de,
              0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485,
              0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d,
              0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4,
              0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc,
              0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823,
              0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b,
              0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12,
              0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a,
              0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41,
              0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49,
              0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70,
              0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78,
              0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f,
              0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067,
              0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e,
              0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256,
              0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d,
              0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405,
              0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c,
              0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634,
              0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab,
              0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3,
              0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a,
              0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92,
              0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9,
              0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1,
              0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8,
              0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0
               };*/
  
  SD_DAT_OUT ;
  SD_CMD_OUT; 
  BYTE b,bit,c=0;
  UINT32 crc=0;
  UINT16 cr=0, value,result = 0;

 typedef union {
    UINT16 val;
    struct {
        UINT16 bit0 : 1;
        UINT16 bit1 : 1;
        UINT16 bit2 : 1;
        UINT16 bit3 : 1;
        UINT16 bit4 : 1;
        UINT16 bit5 : 1;
        UINT16 bit6 : 1;
        UINT16 bit7 : 1;
        UINT16 bit8 : 1;
        UINT16 bit9 : 1;
        UINT16 bit10 : 1;
        UINT16 bit11 : 1;
        UINT16 bit12 : 1;
        UINT16 bit13 : 1;
        UINT16 bit14 : 1;
        UINT16 bit15 : 1;
    } bits;
} CRCREGS;
    
CRCREGS regs;
    
void crcInitRegisters()
{
    regs.val = 0xffff;
}
       
UINT16 crcGetRegisters()
{
    return regs.val;
}

void crcInputBit(BYTE in)
{
    BYTE a;
    a = regs.bits.bit0 ^ in;
    regs.val >>= 1;
    if(a) regs.val ^= 0x8408;
}
crcInitRegisters();

  UINT32  i,j,k;
  lba+=101; 
  for(j=0;j<seccnt;j++)
  {
    {
      Ncc();
      cmd_buffer[0] = cmd24[0];
      cmd_buffer[1] = (lba>>15)&0xff; 
      cmd_buffer[2] = (lba>>7)&0xff;
      cmd_buffer[3] = (lba<<1)&0xff;
      cmd_buffer[4] = 0;
      lba++;
      send_cmd(cmd_buffer); 
      Ncr();
      if(response_R(1)>1) //response too long or crc error
      return 1;
    } 
    
   Ncr();
   

 
   SD_CLK_LOW;
   SD_DAT_LOW; 
   SD_CLK_HIGH; 
 
   
   //SD_DAT_LOW; 
   
   for(i=0; i < 512; i++)  
   {
    b = buff[ i ];
    //buff++;
    for(k=0; k<8; k++)  
    {
      SD_CLK_LOW;   
      if(b&0x80)        
      SD_DAT_HIGH; 
      else 
      SD_DAT_LOW;     
      SD_CLK_HIGH; 
      crcInputBit(( buff[ i ] >> k) & 1);        
      b<<=1;   
    }   
   }  
      
      /*for (i = 0; i < 512; i++)
      { 
       result = (result << 8) ^ (UINT16)CRCTable[(result >> 8) ^ *buff++];
       //buff++;       
      }
      cr = result;*/     

   /* cr = 0xffff;

    for (i = 0; i < 512; ++i) 
{
        value = buff[i];

        for (bit = 0; bit < 8; ++bit)
 {
            cr ^= (value & 0x01);
            cr = ( cr & 0x01 ) ? ( cr >> 1 ) ^ 0x8408 : ( cr >> 1 );
            value = value >> 1;
        } // END for
    } // END for

    cr = cr ^ 0xffff;*/
      
      
     
 cr = ~crcGetRegisters();
 crc = cr & 0xffff ;  
 crc =((crc<<1)|0x01);
 
  for(k=0; k<17; k++)  
  {
    SD_CLK_LOW;
    if(crc&0x10000)
    SD_DAT_HIGH;
    else
    SD_DAT_LOW; 
    SD_CLK_HIGH;
    crc<<=1;
  }      
 } 
 
   SD_DAT_IN;
   
   while(1)
    {
      SD_CLK_LOW;
      SD_CLK_HIGH;
      if(!(SD_TEST_DAT))
      for(i=0;i<8;i++)    //8bit一字節(jié)
         {
           SD_CLK_LOW;
           SD_CLK_HIGH;      //送時鐘，需注意，從card讀取DATA或者RSP在上升沿采樣。
           c <<= 1;            //讀DAT線   c = c <<1   這里的賦值方式和有創(chuàng)意，把DAT0上面的傳給c 
           if(SD_TEST_DAT)     c |= 0x01;   // c =  c | 0x01 
           
          } 
        
    }
  printf("%x \n",c);

 
        
   return b; 
}

//-------------------------------------------------------------------------
BYTE send_cmd(BYTE *in)
{
  int i,j;
  BYTE b,crc=0;
  SD_CMD_OUT;
  for(i=0; i < 5; i++)
  {
    b = in[i];
    for(j=0; j<8; j++)
    {
      SD_CLK_LOW;
      if(b&0x80)
      SD_CMD_HIGH;
      else
      SD_CMD_LOW; 
      crc <<= 1;
      SD_CLK_HIGH;
      if((crc ^ b) & 0x80)
      crc ^= 0x09;
      b<<=1;
    } 
    crc &= 0x7f; 
  }  
  crc =((crc<<1)|0x01);
  b = crc; 
  for(j=0; j<8; j++)
  {
    SD_CLK_LOW;
    if(crc&0x80)
    SD_CMD_HIGH;
    else
    SD_CMD_LOW; 
    SD_CLK_HIGH;
    crc<<=1;
  }    
  return b;   
}
//-------------------------------------------------------------------------
#endif
?? 文件大小 898 K
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