i2c.c

Mouse for USB demo, based on STR710

* Function Name  : I2C_ByteSend
* Description    : Send a single byte of data.
* Input          : I2Cx ( I2C0 or I2C1 )
*                  Data : the byte to be sent to the slave
* Return         : None.
*******************************************************************************/
void I2C_ByteSend (I2C_TypeDef *I2Cx, u8 Data)
{
  //Wait until the I2C_BTF bit is set
  while ((I2Cx->SR1 & 0x08)==0);

  //Write in the DR register the byte to be sent
  I2Cx->DR = Data;
}

/*******************************************************************************
* Function Name  : I2C_BufferSend
* Description    : Send data from a buffer whose number of bytes is known
* Input          : I2Cx ( I2C0 or I2C1 )
*                  PtrToBuffer :pointer to the byte of buffer to be transmitted.
*                  NbOfBytes:Number of byte of the buffer
* Return         : I2C_Tx_Status :transmission status (I2C_TX_AF, I2C_TX_ARLO,
*                  I2C_TX_BERR,I2C_TX_DATA_OK)
*******************************************************************************/
I2C_Tx_Status I2C_BufferSend (I2C_TypeDef *I2Cx, u8 *PtrToBuffer, u8 NbOfBytes)
{
  u8 Interruption_Status;
  u8 SentBytes;
  u8 error;
  I2C_Tx_Status I2C_TXTMP;

  //Test of the interrupt status
  Interruption_Status=0;
  Interruption_Status=I2Cx->CR & 0x01;
  I2C_ITConfig (I2Cx, DISABLE);
  //Wait till I2C_BTF bit is set
  while ((I2Cx->SR1 & 0x08 )==0);
  SentBytes=0;
  while (SentBytes<NbOfBytes)
  {
    I2Cx->DR= *(PtrToBuffer+SentBytes);
    //Wait till I2C_BTF bit is set or error detected
    do
      error = I2Cx->SR2 & 0x16;
    while ((I2Cx->SR1 & 0x08)==0 && error==0);
    // In case of error exit
    if (error) break;
    // increment SentBytes counter
    SentBytes++;
  }
  if (error)
  {
    if (error & 0x10)
      // I2C_TX_AF if Acknowledge failure is detected
      I2C_TXTMP = I2C_TX_AF;
    if (error & 0x02)
      //I2C_TX_ARLO if the ARLO bit is set in the SR2 register
      I2C_TXTMP = I2C_TX_ARLO;
    if (error & 0x04)
      // I2C_TX_BERR if the BERR bit is set in the SR2 register
      I2C_TXTMP=  I2C_TX_BERR;
  }
  else
    //I2C_TX_DATA_OK to show that the buffer is well sent
    I2C_TXTMP= I2C_TX_DATA_OK;

  //Restore the interrupt status
  if (Interruption_Status==1)
  I2C_ITConfig (I2Cx, ENABLE);

  return I2C_TXTMP;
}

/*******************************************************************************
* Function Name  : I2C_StringSend
* Description    : Send data from a buffer
* Input          : I2Cx ( I2C0 or I2C1 )
*                  PtrToBuffer :pointer to the byte of string to be transmitted.
* Return         : I2C_Tx_Status :transmission status (I2C_TX_AF, I2C_TX_ARLO,
*                  I2C_TX_BERR,I2C_TX_DATA_OK)
*******************************************************************************/
I2C_Tx_Status I2C_StringSend (I2C_TypeDef *I2Cx, char *PtrToString)
{
  u8 NbOfBytes=0;
  // count the number of byte composing the string passed as parameter.
  while (*(PtrToString+NbOfBytes)!= '\0')
    NbOfBytes++;
  // call I2C_BufferSend function to execute the send part
  return I2C_BufferSend (I2Cx,(u8 *)PtrToString,NbOfBytes);
}

/*******************************************************************************
* Function Name  : I2C_TransmissionStatus
* Description    : Report the NewState of the transmission
* Input          : I2Cx ( I2C0 or I2C1 )
* Return         : I2C_Tx_Status :transmission status (I2C_TX_NO, I2C_TX_SB,
*                   I2C_TX_AF, I2C_TX_ARLO, I2C_TX_BERR,I2C_TX_ADD_OK,
*                   I2C_TX_DATA_OK,I2C_TX_ONGOING)
*******************************************************************************/
I2C_Tx_Status I2C_TransmissionStatus (I2C_TypeDef *I2Cx)
{
  u8 SR1value;
  u8 SR2value;
  I2C_Tx_Status NewState;

  SR1value = I2Cx->SR1;
  SR2value = I2Cx->SR2;
  if ((I2Cx->SR1&0x10)==0)
    NewState=I2C_TX_NO;
  else if (I2Cx->SR1&0x01)
    //I2C_SB bit is set
    NewState=I2C_TX_SB;
  else if ((SR2value & 0x10)&&(I2Cx->CR&0x04))
    //I2C_ACK &I2C_AF are both set
    NewState=I2C_TX_AF;
  else if (SR2value & 0x04)
    //I2C_ARLO is set in multimaster mode
    NewState=I2C_TX_ARLO;
  else if (SR2value & 0x02)
    //I2C_BERR bit is set
    NewState=I2C_TX_BERR;
  else if ((SR1value & 0x80)&& (I2Cx->SR2&0x20))
    //I2C_EVF and I2C_ENDAD are both set
    NewState=I2C_TX_ADD_OK;
  else if ((I2Cx->SR1&0x20)&& (I2Cx->SR1&0x08))
    //I2C_TRA and I2C_BTF are both set
    NewState=I2C_TX_DATA_OK;
  else
    NewState=I2C_TX_ONGOING;

  return NewState;
}

/*******************************************************************************
* Function Name  : I2C_ByteReceive
* Description    : Returns the received byte.
* Input          : I2Cx ( I2C0 or I2C1 )
* Return         : the byte received
*******************************************************************************/
u8 I2C_ByteReceive (I2C_TypeDef *I2Cx)
{
  //Wait till I2C_BTF bit is set
  while ((I2Cx->SR1 & 0x08)==0);
  return I2Cx->DR;
}

/*******************************************************************************
* Function Name  : I2C_BufferReceive
* Description    : received a buffer. and return the status of error.
* Input          : I2Cx ( I2C0 or I2C1 )
*                  PtrToBuffer :pointer to the byte of buffer received.
*                  NbOfBytes:Number of byte to be received
* Return         : I2C_Rx_Status:the NewState of the reception (,I2C_RX_AF,
*                               I2C_RX_ARLO,I2C_RX_BERR, I2C_RX_DATA_OK)
*******************************************************************************/
I2C_Rx_Status I2C_BufferReceive (I2C_TypeDef *I2Cx, u8 *PtrToBuffer, u8 NbOfBytes)
{
  u8 Interruption_Status;
  u8 ReceivedBytes;
  u8 error;
  I2C_Rx_Status I2C_RXTMP;

  //Test of the interrupt status
  Interruption_Status=0;
  Interruption_Status=I2Cx->CR & 0x01;
  I2C_ITConfig (I2Cx, DISABLE);
  ReceivedBytes=0;
  while (ReceivedBytes<NbOfBytes)
  {
    do
      error = I2Cx->SR2 & 0x16;
    while ((I2Cx->SR1 & 0x08)==0 && !error);
    if (error==0)
    // No error detected
    {
      *(PtrToBuffer+ReceivedBytes) = I2Cx->DR;
      ReceivedBytes++;
    }
    else break;
  }
  if (error)
  {
    if (error & 0x10)
      // I2C_RX_AF if Acknowledge failure is detected
      I2C_RXTMP= I2C_RX_AF;
    else if (error & 0x02)
      // I2C_RX_ARLO if the ARLO bit is set in the SR2 register
      I2C_RXTMP=  I2C_RX_ARLO;
    else if (error & 0x04)
      // I2C_RX_BERR if the BERR bit is set in the SR2 register
      I2C_RXTMP=  I2C_RX_BERR;
  }
  else
    //I2C_RX_DATA_OK to show that the buffer is well sent
    I2C_RXTMP= I2C_RX_DATA_OK;

  //Restore the interrupt status
  if (Interruption_Status==1)
  I2C_ITConfig (I2Cx, ENABLE);

  return I2C_RXTMP;
}

/*******************************************************************************
* Function Name  :I2C_ReceptionStatus
* Description    : Report the reception NewState.
* Input          : I2Cx ( I2C0 or I2C1 )
* Return         : I2C_Rx_Status:the NewState of the reception ( I2C_RX_NO,
*                  I2C_RX_SB,I2C_RX_AF,I2C_RX_ARLO,I2C_RX_BERR,I2C_RX_ADD_OK,
*                  I2C_RX_DATA_OK, I2C_RX_ONGOING)
*******************************************************************************/
I2C_Rx_Status I2C_ReceptionStatus (I2C_TypeDef *I2Cx)
{
  u8 SR1value;
  u8 SR2value;
  I2C_Rx_Status NewState;
  SR1value= I2Cx->SR1;
  SR2value= I2Cx->SR2;

  if ((I2Cx->SR1&0x10) == 0)
    NewState=I2C_RX_NO;
  else if (I2Cx->SR1&0x01)
    //I2C_SB bit is set
    NewState=I2C_RX_SB;
  else if ((SR2value & 0x10) && (I2Cx->CR&0x04))
    //I2C_ACK &I2C_AF are both set
    NewState=I2C_RX_AF;
  else if (SR2value & 0x04)
    //I2C_ARLO is set
    NewState=I2C_RX_ARLO;
  else if (SR2value & 0x02)
    //I2C_BERR bit is set
    NewState=I2C_RX_BERR;
  else if ((SR1value & 0x80) && (I2Cx->SR1&0x08)==0)
    //2C_EVF is set & I2C_BTF is not set
    NewState=I2C_RX_ADD_OK;
  else if ((I2Cx->SR1&0x20)==0 && (I2Cx->SR1&0x08))
    //II2C_TRA is cleared & I2C_BTF is set
    NewState=I2C_RX_DATA_OK;
  else
  NewState=I2C_RX_ONGOING;
  return NewState;
}

/******************* (C) COPYRIGHT 2003 STMicroelectronics *****END OF FILE****/