关于SD卡内存大小的计算

李清界 · 发表于 2012-2-23 18:55:47

  //C_SIZE
    i = csd[6]&0x03;
    i<<=8;
    i += csd[7];
    i<<=2;
    i += ((csd[8]&0xc0)>>6);
        //C_SIZE_MULT
    r1 = csd[9]&0x03;
    r1<<=1;
    r1 += ((csd[10]&0x80)>>7);
  //BLOCKNR
    r1+=2;
    temp = 1;
    while(r1)
    {
      temp*=2;
      r1--;
    }
    Capacity = ((u32)(i+1))*((u32)temp);

        // READ_BL_LEN
    i = csd[5]&0x0f;

        //BLOCK_LEN
    temp = 1;
    while(i)
    {
      temp*=2;
      i--;
    }
        //The final result
    Capacity *= (u32)temp;//字节为单位
这段程序该怎么样理解呢？？
请高手解答一下哦哦!