SD/MMC CSD寄存器 V1.0和V2.0详解（如何读写SD/MMC卡）
1.如何计算V1.0 SD卡容量计算C_SIZE:C_SIZE = (csd[8] >> 6) + ((uint16_t)csd[7] 计算 C_SIZE_MULT:C_SIZE_MULT = ((csd[10] & 128) >> 7) + ((csd[9] & 3) 计算READ_BL_LEN:READ_BL_LEN = csd[5] & 15;
