i2c.c

用MSP430 IO 口模拟I2C通讯

  vDelay ( I2C_DELAY );

}

/************** Send Byte *******************/
#define I2C_DELAY_for_writting 8
void  I2C_SendByte_for_writting ( unsigned char ucData )
{
  register unsigned char i;

  //while ( (cI2C_Status != I2C_OK));// & i<250)        // error -> do not send Byte, BUS is not free
                               // this error check can be embedded in the "for" loop
                                      // to cover errors that occured during transmision

  for ( i=0; i<8; i++ )
  {
    if ( ucData & 0x80 )              // bit 7 - check and  -> if(bit==1) ...
    {                                 // set data line to the MSB (bit 7)
      I2C_PORT_DIR &= ~SDA;           // SDA pin = 1
    } else {
      I2C_PORT_DIR |= SDA;            // SDA pin = 0
    }

    vDelay ( I2C_DELAY_for_writting );
    I2C_SCL_High_for_CP_writting ();                  // SCL pin = 1
   // vDelay ( I2C_DELAY_for_writting );
    I2C_PORT_DIR |= SCL;              // SCL pin = 0
   // vDelay ( I2C_DELAY_for_writting );

    ucData = ucData << 1;             // next bit will be 6 ... 0
  }

//  vDelay ( I2C_Delay );
  I2C_PORT_DIR &= ~SDA;               // SDA pin = high - listen for ACK
  //vDelay ( I2C_DELAY_for_writting );
  I2C_SCL_High_for_CP_writting ();                    // SCL pin = high
  //vDelay ( I2C_DELAY_for_writting );

  if ( I2C_PORT_IN & SDA )            // bit check and -> if(bit==1) SDA is high = NACK
  {
    cI2C_Status = I2C_NACK;           // NACK
  }

//  vDelay ( I2C_Delay );
  I2C_PORT_DIR |= SCL;                // SCL pin = 0
 // vDelay ( I2C_DELAY_for_writting );

}

/************** Get Byte ***************/

unsigned char I2C_GetByte ( unsigned char ucLastByteFlag )
{
  register unsigned char  i,
                          ucRxData;     // received byte

  if ( cI2C_Status != I2C_OK )          // error -> do not read Byte
    return(cI2C_Status);

  ucRxData = 0;
  for ( i = 0; i < 8 ; i++ )
  {
    I2C_SCL_High ();                    // SCL pin = high
    vDelay ( I2C_DELAY );

    ucRxData = ucRxData << 1;           // shifts the recieved bits

    if ( I2C_PORT_IN & SDA )            // is SDA = 1
    {
      ucRxData |= 0x01;                 // sets bit 0
    }

    I2C_PORT_DIR |= SCL;                // SCL pin = 0
    vDelay ( I2C_DELAY );
  }

  if ( ucLastByteFlag == 0 )
  {
    I2C_PORT_DIR &= ( SDA );            // SDA pin = low => ACK
    I2C_SCL_High ();                    // SCL pin = high
    vDelay ( I2C_DELAY );
    I2C_PORT_DIR |= SCL;                // SCL pin = 0
  } else
  {                                     // last byte -> send NACK
    I2C_PORT_DIR &= ( ~SDA );           // SDA pin = high => NACK
    I2C_SCL_High ();                    // SCL pin = high
    vDelay ( I2C_DELAY );
    I2C_PORT_DIR |= SCL;                // SCL pin = 0
  }

  return ( ucRxData );
}



unsigned char I2C_GetByte_for_CP ( unsigned char ucLastByteFlag )
{
  register unsigned char  i,
                          ucRxData;     // received byte

  if ( cI2C_Status != I2C_OK )          // error -> do not read Byte
    return(cI2C_Status);

  ucRxData = 0;
  for ( i = 0; i < 8 ; i++ )
  {
    I2C_SCL_High_for_CP_writting ();                    // SCL pin = high
   // vDelay ( I2C_DELAY );

    ucRxData = ucRxData << 1;           // shifts the recieved bits

    if ( I2C_PORT_IN & SDA )            // is SDA = 1
    {
      ucRxData |= 0x01;                 // sets bit 0
    }

    I2C_PORT_DIR |= SCL;                // SCL pin = 0
   // vDelay ( I2C_DELAY );
  }

  if ( ucLastByteFlag == 0 )
  {
    I2C_PORT_DIR &= ( SDA );            // SDA pin = low => ACK
    I2C_SCL_High_for_CP_writting ();                    // SCL pin = high
    //vDelay ( I2C_DELAY );
    I2C_PORT_DIR |= SCL;                // SCL pin = 0
  } else
  {                                     // last byte -> send NACK
    I2C_PORT_DIR &= ( ~SDA );           // SDA pin = high => NACK
    I2C_SCL_High_for_CP_writting ();                    // SCL pin = high
    //vDelay ( I2C_DELAY );
    I2C_PORT_DIR |= SCL;                // SCL pin = 0
  }

  return ( ucRxData );
}
/************** Get Two Bytes ***************/

unsigned char I2C_Get_two_Bytes ( unsigned char ucLastByteFlag )
{
  register unsigned int  i,
                          ucRxData;     // received byte

  if ( cI2C_Status != I2C_OK )          // error -> do not read Byte
    return(cI2C_Status);

  ucRxData = 0;
  for ( i = 0; i < 16 ; i++ )
  {
    I2C_SCL_High ();                    // SCL pin = high
   // vDelay ( I2C_DELAY );

    ucRxData = ucRxData << 1;           // shifts the recieved bits

    if ( I2C_PORT_IN & SDA )            // is SDA = 1
    {
      ucRxData |= 0x01;                 // sets bit 0
    }

    I2C_PORT_DIR |= SCL;                // SCL pin = 0
    vDelay ( 10 );
  }

  if ( ucLastByteFlag == 0 )
  {
    I2C_PORT_DIR &= ( SDA );            // SDA pin = low => ACK
    I2C_SCL_High ();                    // SCL pin = high
    vDelay ( I2C_DELAY );
    I2C_PORT_DIR |= SCL;                // SCL pin = 0
  } else
  {                                     // last byte -> send NACK
    I2C_PORT_DIR &= ( ~SDA );           // SDA pin = high => NACK
    I2C_SCL_High ();                    // SCL pin = high
    vDelay ( I2C_DELAY );
    I2C_PORT_DIR |= SCL;                // SCL pin = 0
  }

  return ( ucRxData );
}
/************************************************************************/
/*********************************************/
void I2C_DelayWriteByteNum_for_cp ( unsigned char ucDevAddr,
                                    unsigned char ucDataAddr,
                                    unsigned char const *pucData,
                                    unsigned char ucNumBytes,
                                    unsigned int  uivDelay )
{
  char i;
  I2C_MASK_IE_PORT &= ~I2C_IRQ_MASK;      // forbid IRQ

  vDelay ( uivDelay );
                                          // move IRQ mask here ???
  I2C_SendStart();

  if ( cI2C_Status == I2C_OK )
  {
    I2C_SendByte( ucDevAddr );
    I2C_SendByte( ucDataAddr );
    for ( i = 0; i < ucNumBytes; i++ )    // does not check cI2C_Status for bytes
      {
      I2C_SendByte_for_writting( *(pucData+i ) );
      
      }
  }
 //  vDelay(300);
  I2C_SendStop();

  ucI2C_Err = cI2C_Status;
  I2C_MASK_IE_PORT |= I2C_IRQ_MASK;      // allow IRQ
  vDelay(8000);
}


void  I2C_Send_pure_Byte ( unsigned char ucData )
{
  register unsigned char i;

  if ( cI2C_Status != I2C_OK )        // error -> do not send Byte, BUS is not free
    return;                           // this error check can be embedded in the "for" loop
                                      // to cover errors that occured during transmision

  for ( i=0; i<8; i++ )
  {
    if ( ucData & 0x80 )              // bit 7 - check and  -> if(bit==1) ...
    {                                 // set data line to the MSB (bit 7)
      I2C_PORT_DIR &= ~SDA;           // SDA pin = 1
    } else {
      I2C_PORT_DIR |= SDA;            // SDA pin = 0
    }

    vDelay ( I2C_DELAY );
    I2C_SCL_High ();                  // SCL pin = 1
    vDelay ( I2C_DELAY );
    I2C_PORT_DIR |= SCL;              // SCL pin = 0
    vDelay ( I2C_DELAY );

    ucData = ucData << 1;             // next bit will be 6 ... 0
  }
}
void  I2C_Send_Byte_end ( void )
{
//  vDelay ( I2C_Delay );
  I2C_PORT_DIR &= ~SDA;               // SDA pin = high - listen for ACK
  vDelay ( 10 );
  I2C_SCL_High ();                    // SCL pin = high
  vDelay ( 10 );

  if ( I2C_PORT_IN & SDA )            // bit check and -> if(bit==1) SDA is high = NACK
  {
    cI2C_Status = I2C_NACK;           // NACK
  }

//  vDelay ( I2C_Delay );
  I2C_PORT_DIR |= SCL;                // SCL pin = 0
  vDelay ( I2C_DELAY );

}

unsigned char ucI2C_Read_first_Byte ( unsigned char ucDevAddr,
                             unsigned char ucDataAddr)
{
  unsigned char ucData;
  
  I2C_MASK_IE_PORT &= ~I2C_IRQ_MASK;      // forbid IRQ

_NOP();
  I2C_SendStart();
  if ( cI2C_Status == I2C_OK )
  {
    I2C_SendByte( ucDevAddr );                // write address !!
    I2C_SendByte( ucDataAddr );
    I2C_SendStop();
    I2C_SendStart();
    I2C_SendByte( ucDevAddr | I2C_READ );     // read address
    ucData  = I2C_GetByte( I2C_LAST_BYTE );    // return value
    
    }
    return ucData;
}
unsigned char continue_to_read()
{   unsigned char ucData;
    I2C_SendStop();
    vDelay ( I2C_DELAY_for_writting );
    I2C_SendStart();
   vDelay ( I2C_DELAY_for_writting );
    I2C_SendByte_for_writting( 0x21 );     // read address
    ucData  = I2C_GetByte_for_CP( I2C_LAST_BYTE );    // return value
    vDelay ( I2C_DELAY_for_writting );
    return ucData;
}

void read_end(void)
{
  I2C_SendStop();
vDelay ( I2C_DELAY_for_writting );
  ucI2C_Err = cI2C_Status;
  I2C_MASK_IE_PORT |= I2C_IRQ_MASK;      // allow IRQ
  vDelay ( I2C_DELAY_for_writting );
  
}