获取SDHC卡CSD信息程序讲解

sdhc卡

/**
  * @brief  Read the CSD card register.
  *         Reading the contents of the CSD register in SPI mode is a simple 
  *         read-block transaction.
  * @param  SD_csd: pointer on an CSD register structure
  * @retval The SD response: 
  *         - SD_RESPONSE_FaiLURE: sequence failed
  *         - SD_RESPONSE_NO_ERROR: Sequence succeed
  */
SD_Error SD_GetCSDRegister(SD_CSD* SD_csd)
{
  uint32_t i = 0;
  SD_Error rvalue = SD_RESPONSE_FAILURE;
  uint8_t CSD_Tab[16];

  /*!< SD chip select low */
  SD_CS_LOW();
  /*!< Send CMD9 (CSD register) or CMD10(CSD register) */
  SD_SendCmd(SD_CMD_SEND_CSD, 0, 0xFF);
  /*!< Wait for response in the R1 format (0x00 is no errors) */
  if (!SD_GetResponse(SD_RESPONSE_NO_ERROR))
  {
    if (!SD_GetResponse(SD_START_DATA_SINGLE_BLOCK_READ))
    {
      for (i = 0; i < 16; i++)
      {
        /*!< Store CSD register value on CSD_Tab */
        CSD_Tab[i] = SD_ReadByte();
      }
    }
    /*!< Get CRC bytes (not really needed by us, but required by SD) */
    SD_WriteByte(SD_dummy_BYTE);
    SD_WriteByte(SD_DUMMY_BYTE);
    /*!< Set response value to success */
    rvalue = SD_RESPONSE_NO_ERROR;
  }
  /*!< SD chip select high */
  SD_CS_HIGH();
  /*!< Send dummy byte: 8 Clock pulses of delay */
  SD_WriteByte(SD_DUMMY_BYTE);

  /*!< Byte 0 */
  SD_csd->CSDStruct = (CSD_Tab[0] & 0xC0) >> 6;
  SD_csd->SysSpecVersion = (CSD_Tab[0] & 0x3C) >> 2;
  SD_csd->Reserved1 = CSD_Tab[0] & 0x03;

  /*!< Byte 1 */
  SD_csd->TAAC = CSD_Tab[1];

  /*!< Byte 2 */
  SD_csd->NSAC = CSD_Tab[2];

  /*!< Byte 3 */
  SD_csd->MaxBusClkFrec = CSD_Tab[3];

  /*!< Byte 4 */
  SD_csd->CardComdClasses = CSD_Tab[4] << 4;

  /*!< Byte 5 */
  SD_csd->CardComdClasses |= (CSD_Tab[5] & 0xF0) >> 4;
  SD_csd->RdBlockLen = CSD_Tab[5] & 0x0F;

  /*!< Byte 6 */
  SD_csd->PartBlockRead = (CSD_Tab[6] & 0x80) >> 7;
  SD_csd->WrBlockMisalign = (CSD_Tab[6] & 0x40) >> 6;
  SD_csd->RdBlockMisalign = (CSD_Tab[6] & 0x20) >> 5;
  SD_csd->DSRImpl = (CSD_Tab[6] & 0x10) >> 4;
  SD_csd->Reserved2 = 0; /*!< Reserved */

  SD_csd->DeviceSize = (CSD_Tab[6] & 0x03) << 10;

	//V1.0 SDSC card info.
  if ((SD_Type == SD_TYPE_V1) || (SD_Type == SD_TYPE_V2))
	{
		/*!< Byte 7 */
		SD_csd->DeviceSize |= (CSD_Tab[7]) << 2;

		/*!< Byte 8 */
		SD_csd->DeviceSize |= (CSD_Tab[8] & 0xC0) >> 6;

		SD_csd->MaxRdCurrentVDDMin = (CSD_Tab[8] & 0x38) >> 3;
		SD_csd->MaxRdCurrentVDDMax = (CSD_Tab[8] & 0x07);

		/*!< Byte 9 */
		SD_csd->MaxWrCurrentVDDMin = (CSD_Tab[9] & 0xE0) >> 5;
		SD_csd->MaxWrCurrentVDDMax = (CSD_Tab[9] & 0x1C) >> 2;
		SD_csd->DeviceSizeMul = (CSD_Tab[9] & 0x03) << 1;
		/*!< Byte 10 */
		SD_csd->DeviceSizeMul |= (CSD_Tab[10] & 0x80) >> 7;
  }
	//V2.0 SDHC card info.
	else if (SD_Type == SD_TYPE_V2HC)
	{
		SD_csd->DeviceSize = (CSD_Tab[7] & 0x3F) << 16;

		SD_csd->DeviceSize |= (CSD_Tab[8] << 8);
    
		SD_csd->DeviceSize |= (CSD_Tab[9]);		
	}
		
		
  SD_csd->eraseGrSize = (CSD_Tab[10] & 0x40) >> 6;
  SD_csd->EraseGrMul = (CSD_Tab[10] & 0x3F) << 1;

  /*!< Byte 11 */
  SD_csd->EraseGrMul |= (CSD_Tab[11] & 0x80) >> 7;
  SD_csd->WrProtectGrSize = (CSD_Tab[11] & 0x7F);

  /*!< Byte 12 */
  SD_csd->WrProtectGrEnable = (CSD_Tab[12] & 0x80) >> 7;
  SD_csd->ManDeflECC = (CSD_Tab[12] & 0x60) >> 5;
  SD_csd->WrSpeedFact = (CSD_Tab[12] & 0x1C) >> 2;
  SD_csd->MaxWrBlockLen = (CSD_Tab[12] & 0x03) << 2;

  /*!< Byte 13 */
  SD_csd->MaxWrBlockLen |= (CSD_Tab[13] & 0xC0) >> 6;
  SD_csd->WriteBlockPaPartial = (CSD_Tab[13] & 0x20) >> 5;
  SD_csd->Reserved3 = 0;
  SD_csd->ContentProtectAPPli = (CSD_Tab[13] & 0x01);

  /*!< Byte 14 */
  SD_csd->FileFormatGrouop = (CSD_Tab[14] & 0x80) >> 7;
  SD_csd->CopyFlag = (CSD_Tab[14] & 0x40) >> 6;
  SD_csd->PermWrProtect = (CSD_Tab[14] & 0x20) >> 5;
  SD_csd->TempWrProtect = (CSD_Tab[14] & 0x10) >> 4;
  SD_csd->FileFormat = (CSD_Tab[14] & 0x0C) >> 2;
  SD_csd->ECC = (CSD_Tab[14] & 0x03);

  /*!< Byte 15 */
  SD_csd->CSD_CRC = (CSD_Tab[15] & 0xFE) >> 1;
  SD_csd->Reserved4 = 1;

  /*!< Return the reponse */
  return rvalue;
}

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