microsd.c

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  /* Check if the MSD acknowledged the write block command: R1 response (0x00: no errors) */
  if (!MSD_GetResponse(MSD_RESPONSE_NO_ERROR))
  {
    /* Send a dummy byte */
    MSD_WriteByte(DUMMY);
    /* Send the data token to signify the start of the data */
    MSD_WriteByte(0xFE);
    /* Write the block data to MSD : write count data by block */
    for (i = 0; i < NumByteToWrite; i++)
    {
      /* Send the pointed byte */
      MSD_WriteByte(*pBuffer);
      /* Point to the next location where the byte read will be saved */
      pBuffer++;
    }
		
		/* Send DUMMY bytes when the number of data to be written are lower
		   than the MSD card BLOCK size (512 Byte) */
		for (; i != BLOCK_SIZE; i++)
    {
      /* Send the pointed byte */
      MSD_WriteByte(DUMMY);
	  }
	
    /* Put CRC bytes (not really needed by us, but required by MSD) */
    MSD_ReadByte();
    MSD_ReadByte();
    /* Read data response */
    if (MSD_GetDataResponse() == MSD_DATA_OK)
    {
      rvalue = MSD_RESPONSE_NO_ERROR;
    }
  }

  /* MSD chip select high */
  MSD_ChipSelect(DISABLE);
  /* Send dummy byte: 8 Clock pulses of delay */
  MSD_WriteByte(DUMMY);
  /* Returns the reponse */
  return rvalue;
}

/**
  * @brief Get the data MSD card reponse status.
  * @par Parameters:
  * None
  * @retval u8 The MSD response status
  * Read data response xxx0<status>1.
  * - status 010: Data accepted.
  * - status 101: Data rejected due to a crc error.
  * - status 110: Data rejected due to a Write error.
  * - status 111: Data rejected due to other error.
  * @par Required preconditions:
  * None
  * @par Functions called:
  * None
  */
u8 MSD_GetDataResponse(void)
{
  u32 i = 0;
  u8 response, rvalue;

  while (i <= 64)
  {
    /* Read resonse */
    response = MSD_ReadByte();
    /* Mask unused bits */
    response &= 0x1F;

    switch (response)
    {
      case MSD_DATA_OK:
      {
        rvalue = MSD_DATA_OK;
        break;
      }

      case MSD_DATA_CRC_ERROR:
        return MSD_DATA_CRC_ERROR;

      case MSD_DATA_WRITE_ERROR:
        return MSD_DATA_WRITE_ERROR;

      default:
      {
        rvalue = MSD_DATA_OTHER_ERROR;
        break;
      }
    }
    /* Exit loop in case of data ok */
    if (rvalue == MSD_DATA_OK)
      break;
    /* Increment loop counter */
    i++;
  }
  /* Wait null data */
  while (MSD_ReadByte() == 0);
  /* Return response */
  return response;
}

/**
  * @brief Read a block from the MSD card.
  * @param[in] pBuffer pointer to the buffer that receives the data read from the MSD.
  * @param[in] ReadAddr MSD's internal address to read from.
  * @param[in] NumByteToRead number of bytes to read from the MSD.
  * @retval u8 The MSD response
  * - MSD_RESPONSE_FAILURE: Sequence failed.
  * - MSD_RESPONSE_NO_ERROR: Sequence succeed.
  * @par Required preconditions:
  * None
  * @par Functions called:
  * None
  */
u8 MSD_ReadBlock(u8 *pBuffer, u32 ReadAddr, u16 NumByteToRead)
{
  u32 i = 0;
  u8 rvalue = MSD_RESPONSE_FAILURE;

  /* MSD chip select low */
  MSD_ChipSelect(ENABLE);
  /* Send CMD17 (MSD_READ_SINGLE_BLOCK) to read one block */
  MSD_SendCmd(MSD_READ_SINGLE_BLOCK, ReadAddr, 0xFF);

  /* Check if the MSD acknowledged the read block command: R1 response (0x00: no errors) */
  if (!MSD_GetResponse(MSD_RESPONSE_NO_ERROR))
  {
    /* Now look for the data token to signify the start of the data */
    if (!MSD_GetResponse(MSD_START_DATA_SINGLE_BLOCK_READ))
    {
      /* Read the MSD block data : read NumByteToRead data */
      for (i = 0; i < NumByteToRead; i++)
      {
        /* Save the received data */
        *pBuffer = MSD_ReadByte();
        /* Point to the next location where the byte read will be saved */
        pBuffer++;
      }
      /* Get CRC bytes (not really needed by us, but required by MSD) */
      MSD_ReadByte();
      MSD_ReadByte();
      /* Set response value to success */
      rvalue = MSD_RESPONSE_NO_ERROR;
    }
  }

  /* MSD chip select high */
  MSD_ChipSelect(DISABLE);
  /* Send dummy byte: 8 Clock pulses of delay */
  MSD_WriteByte(DUMMY);
  /* Returns the reponse */
  return rvalue;
}

/**
  * @brief Write a buffer (many blocks) in the MSD card.
	* The amount of data to write should be a multiple of MSD card BLOCK size (512 Byte).  
  * @param[in] pBuffer pointer to the buffer containing the data to be written on the MSD.
  * @param[in] WriteAddr address to write on.
  * @param[in] NumByteToWrite number of data to write.
  * @retval u8 The MSD response
  * - MSD_RESPONSE_FAILURE: Sequence failed
  * - MSD_RESPONSE_NO_ERROR: Sequence succeed
  * @par Required preconditions:
  * None
  * @par Functions called:
  * None
  */
u8 MSD_WriteBuffer(u8 *pBuffer, u32 WriteAddr, u32 NumByteToWrite)
{
  u32 i = 0, NbrOfBlock = 0, Offset = 0;
  u8 rvalue = MSD_RESPONSE_FAILURE;

  /* Calculate number of blocks to write */
  NbrOfBlock = NumByteToWrite / BLOCK_SIZE;
  /* MSD chip select low */
  MSD_ChipSelect(ENABLE);

  /* Data transfer */
  while (NbrOfBlock--)
  {
    /* Send CMD24 (MSD_WRITE_BLOCK) to write blocks */
    MSD_SendCmd(MSD_WRITE_BLOCK, WriteAddr + Offset, 0xFF);

    /* Check if the MSD acknowledged the write block command: R1 response (0x00: no errors) */
    if (MSD_GetResponse(MSD_RESPONSE_NO_ERROR))
    {
      return MSD_RESPONSE_FAILURE;
    }
    /* Send dummy byte */
    MSD_WriteByte(DUMMY);
    /* Send the data token to signify the start of the data */
    MSD_WriteByte(MSD_START_DATA_SINGLE_BLOCK_WRITE);
    /* Write the block data to MSD : write count data by block */
    for (i = 0; i < BLOCK_SIZE; i++)
    {
      /* Send the pointed byte */
      MSD_WriteByte(*pBuffer);
      /* Point to the next location where the byte read will be saved */
      pBuffer++;
    }
    /* Set next write address */
    Offset += 512;
    /* Put CRC bytes (not really needed by us, but required by MSD) */
    MSD_ReadByte();
    MSD_ReadByte();
    /* Read data response */
    if (MSD_GetDataResponse() == MSD_DATA_OK)
    {
      /* Set response value to success */
      rvalue = MSD_RESPONSE_NO_ERROR;
    }
    else
    {
      /* Set response value to failure */
      rvalue = MSD_RESPONSE_FAILURE;
    }
  }

  /* MSD chip select high */
  MSD_ChipSelect(DISABLE);
  /* Send dummy byte: 8 Clock pulses of delay */
  MSD_WriteByte(DUMMY);
  /* Returns the reponse */
  return rvalue;
}

/**
  * @brief Read a buffer (many blocks) from the MSD card.
  * @param[in] pBuffer pointer to the buffer that receives the data read from the MSD.
  * @param[in] ReadAddr MSD's internal address to read from.
  * @param[in] NumByteToRead number of bytes to read from the MSD.
  * @retval u8 The MSD response
  * - MSD_RESPONSE_FAILURE: Sequence failed
  * - MSD_RESPONSE_NO_ERROR: Sequence succeed
  * @par Required preconditions:
  * None
  * @par Functions called:
  * None
  */
u8 MSD_ReadBuffer(u8 *pBuffer, u32 ReadAddr, u32 NumByteToRead)
{
  u32 i = 0, NbrOfBlock = 0, Offset = 0;
  u8 rvalue = MSD_RESPONSE_FAILURE;

  /* Calculate number of blocks to read */
  NbrOfBlock = NumByteToRead / BLOCK_SIZE;
  /* MSD chip select low */
  MSD_ChipSelect(ENABLE);

  /* Data transfer */
  while (NbrOfBlock --)
  {
    /* Send CMD17 (MSD_READ_SINGLE_BLOCK) to read one block */
    MSD_SendCmd (MSD_READ_SINGLE_BLOCK, ReadAddr + Offset, 0xFF);
    /* Check if the MSD acknowledged the read block command: R1 response (0x00: no errors) */
    if (MSD_GetResponse(MSD_RESPONSE_NO_ERROR))
    {
      return  MSD_RESPONSE_FAILURE;
    }
    /* Now look for the data token to signify the start of the data */
    if (!MSD_GetResponse(MSD_START_DATA_SINGLE_BLOCK_READ))
    {
      /* Read the MSD block data : read NumByteToRead data */
      for (i = 0; i < BLOCK_SIZE; i++)
      {
        /* Read the pointed data */
        *pBuffer = MSD_ReadByte();
        /* Point to the next location where the byte read will be saved */
        pBuffer++;
      }
      /* Set next read address*/
      Offset += 512;
      /* get CRC bytes (not really needed by us, but required by MSD) */
      MSD_ReadByte();
      MSD_ReadByte();
      /* Set response value to success */
      rvalue = MSD_RESPONSE_NO_ERROR;
    }
    else
    {
      /* Set response value to failure */
      rvalue = MSD_RESPONSE_FAILURE;
    }
  }

  /* MSD chip select high */
  MSD_ChipSelect(DISABLE);
  /* Send dummy byte: 8 Clock pulses of delay */
  MSD_WriteByte(DUMMY);
  /* Returns the reponse */
  return rvalue;
}

/******************* (C) COPYRIGHT 2009 STMicroelectronics *****END OF FILE****/