1.如何计算V1.0 SD卡容量
计算C_SIZE:
C_SIZE = (csd[8] >> 6) + ((uint16_t)csd[7] << 2) + ((uint16_t)(csd[6] & 3) << 10);
计算 C_SIZE_MULT:
C_SIZE_MULT = ((csd[10] & 128) >> 7) + ((csd[9] & 3) << 1);
计算READ_BL_LEN:
READ_BL_LEN = csd[5] & 15;
容量：
memory capacity = (C_SIZE+1)*MULT*BLOCK_LEN
memory capacity = (C_SIZE+1)<<(C_SIZE_MULT+2+BLOCK_LEN);
如果需要转换成Kbyte，左移10位即可实现，也可以把结果除以1024，或者把上面的公式写成如下：
memory capacity = (C_SIZE+1)<<(C_SIZE_MULT+2+BLOCK_LEN-10);
2.如何计算V2.0 SD卡容量
csize = csd[9] + ((uint32_t)csd[8] << 8) + ((uint32_t)(csd[7] & 63) << 16) + 1;
Capacity = csize << 9;
3.识别SD卡版本
uint32_t SD_GetCapacity(void)
{
uint8_t csd[16];
uint32_t Capacity;
uint16_t n;
uint16_t csize;
if(SD_GetCSD(csd)!=0) return 0;
if((csd[0]&0xC0)==0x40)//判断bit126是否为1
{
csize = csd[9] + ((uint32_t)csd[8] << 8) + ((uint32_t)(csd[7] & 63) << 16) + 1;
Capacity = csize << 9;
}
else
{
n = (csd[5] & 0x0F) + ((csd[10] & 0x80) >> 7) + ((csd[9] & 0x03) << 1) + 2;
csize = (csd[8] >> 6) + ((uint16_t)csd[7] << 2) + ((uint16_t)(csd[6] & 0x03) << 10) + 1;
Capacity = (uint32_t)csize << (n - 10);
}
return Capacity;
}
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原文链接：https://blog.csdn.net/meic51/article/details/50521952