/*

 * Project Frontplatte

 *

 * myi2c.c  -  I2C-Bus Commands

 *

 * This file is released under the GNU General Public License. Refer

 * to the COPYING file distributed with this package.

 *

 * (c) 2007 Carsten Presser cpresser AT fsing.uni-sb.de

 *  most parts are taken from AN991 by microchip

 */

#include <p18cxxx.h>

#include "myi2c.h"

#include <i2c.h>

unsigned int PageSize;

unsigned char LDByteWriteI2C( unsigned char ControlByte, unsigned char LowAdd, unsigned char data )

{

  IdleI2C();                          // ensure module is idle

  StartI2C();                         // initiate START condition

  while ( SSPCON2bits.SEN );          // wait until start condition is over 

  WriteI2C( ControlByte );            // write 1 byte - R/W bit should be 0

  IdleI2C();                          // ensure module is idle

  WriteI2C( LowAdd );                 // write address byte to EEPROM

  IdleI2C();                          // ensure module is idle

  WriteI2C ( data );                  // Write data byte to EEPROM

  IdleI2C();                          // ensure module is idle

  StopI2C();                          // send STOP condition

  while ( SSPCON2bits.PEN );          // wait until stop condition is over 

  while (EEAckPolling(ControlByte));  //Wait for write cycle to complete

  return ( 0 );                       // return with no error

}

unsigned char LDByteReadI2C(unsigned char ControlByte)

{

  unsigned char data;

  IdleI2C();                      // ensure module is idle

  StartI2C();                     // initiate START condition

  while ( SSPCON2bits.SEN );      // wait until start condition is over 

  WriteI2C( ControlByte | 0x01 ); // WRITE 1 byte - R/W bit should be 1 for read

  IdleI2C();                      // ensure module is idle

  data = ReadI2C();

  IdleI2C();                      // ensure module is idle

  NotAckI2C();                       // send not ACK condition

  while ( SSPCON2bits.ACKEN );    // wait until ACK sequence is over 

  StopI2C();                      // send STOP condition

  while ( SSPCON2bits.PEN );      // wait until stop condition is over 

  return ( data );                   // return with no error

}

unsigned char LDPageReadI2C( unsigned char ControlByte, unsigned char address, unsigned char *data, unsigned char length )

{

  IdleI2C();                      // ensure module is idle

  StartI2C();                     // initiate START condition

  while ( SSPCON2bits.SEN );      // wait until start condition is over 

  WriteI2C( ControlByte );        // write 1 byte 

  IdleI2C();                      // ensure module is idle

  WriteI2C( address );            // WRITE word address to EEPROM

  IdleI2C();                      // ensure module is idle

  RestartI2C();                   // generate I2C bus restart condition

  while ( SSPCON2bits.RSEN );     // wait until re-start condition is over 

  WriteI2C( ControlByte | 0x01 ); // WRITE 1 byte - R/W bit should be 1 for read

  IdleI2C();                      // ensure module is idle

  getsI2C( data, length );        // read in multiple bytes

  NotAckI2C();                    // send not ACK condition

  while ( SSPCON2bits.ACKEN );    // wait until ACK sequence is over 

  StopI2C();                      // send STOP condition

  while ( SSPCON2bits.PEN );      // wait until stop condition is over 

  return ( 0 );                   // return with no error

}

unsigned char LDPageWriteI2C( unsigned char ControlByte, unsigned char LowAdd, unsigned char *wrptr, unsigned char length)

{

  PageSize = (int)length;

  IdleI2C();                      // ensure module is idle

  StartI2C();                     // initiate START condition

  while ( SSPCON2bits.SEN );      // wait until start condition is over 

  WriteI2C( ControlByte );        // write 1 byte - R/W bit should be 0

  IdleI2C();                      // ensure module is idle

  WriteI2C( LowAdd );             // write LowAdd byte to EEPROM

  IdleI2C();                      // ensure module is idle

  putstringI2C ( wrptr );         // pointer to data for page write

  IdleI2C();                      // ensure module is idle

  StopI2C();                      // send STOP condition

  while ( SSPCON2bits.PEN );      // wait until stop condition is over 

  return ( 0 );                   // return with no error

}

/*

unsigned char HDByteWriteI2C( unsigned char ControlByte, unsigned char HighAdd, unsigned char LowAdd, unsigned char data )

{

  IdleI2C();                      // ensure module is idle

  StartI2C();                     // initiate START condition

  while ( SSPCON2bits.SEN );      // wait until start condition is over 

  WriteI2C( ControlByte );        // write 1 byte - R/W bit should be 0

  IdleI2C();                      // ensure module is idle

  WriteI2C( HighAdd );            // write address byte to EEPROM

  IdleI2C();                      // ensure module is idle

  WriteI2C( LowAdd );             // write address byte to EEPROM

  IdleI2C();                      // ensure module is idle

  WriteI2C ( data );              // Write data byte to EEPROM

  IdleI2C();                      // ensure module is idle

  StopI2C();                      // send STOP condition

  while ( SSPCON2bits.PEN );      // wait until stop condition is over 

  while (EEAckPolling(ControlByte));  //Wait for write cycle to complete

  return ( 0 );                   // return with no error

}

unsigned char HDByteReadI2C( unsigned char ControlByte, unsigned char HighAdd, unsigned char LowAdd, unsigned char *data, unsigned char length )

{

  IdleI2C();                      // ensure module is idle

  StartI2C();                     // initiate START condition

  while ( SSPCON2bits.SEN );      // wait until start condition is over 

  WriteI2C( ControlByte );        // write 1 byte 

  IdleI2C();                      // ensure module is idle

  WriteI2C( HighAdd );            // WRITE word address to EEPROM

  IdleI2C();                      // ensure module is idle

  while ( SSPCON2bits.RSEN );     // wait until re-start condition is over 

  WriteI2C( LowAdd );             // WRITE word address to EEPROM

  IdleI2C();                      // ensure module is idle

  RestartI2C();                   // generate I2C bus restart condition

  while ( SSPCON2bits.RSEN );     // wait until re-start condition is over 

  WriteI2C( ControlByte | 0x01 ); // WRITE 1 byte - R/W bit should be 1 for read

  IdleI2C();                      // ensure module is idle

  getsI2C( data, length );       // read in multiple bytes

  NotAckI2C();                    // send not ACK condition

  while ( SSPCON2bits.ACKEN );    // wait until ACK sequence is over 

  StopI2C();                      // send STOP condition

  while ( SSPCON2bits.PEN );      // wait until stop condition is over 

  return ( 0 );                   // return with no error

}

unsigned char HDPageWriteI2C( unsigned char ControlByte, unsigned char HighAdd, unsigned char LowAdd, unsigned char *wrptr )

{

  IdleI2C();                      // ensure module is idle

  StartI2C();                     // initiate START condition

  while ( SSPCON2bits.SEN );      // wait until start condition is over 

  WriteI2C( ControlByte );        // write 1 byte - R/W bit should be 0

  IdleI2C();                      // ensure module is idle

  WriteI2C( HighAdd );            // write HighAdd byte to EEPROM 

  IdleI2C();                      // ensure module is idle

  WriteI2C( LowAdd );             // write LowAdd byte to EEPROM

  IdleI2C();                      // ensure module is idle

  putstringI2C ( wrptr );         // pointer to data for page write

  IdleI2C();                      // ensure module is idle

  StopI2C();                      // send STOP condition

  while ( SSPCON2bits.PEN );      // wait until stop condition is over 

  return ( 0 );                   // return with no error

}

unsigned char HDSequentialReadI2C( unsigned char ControlByte, unsigned char HighAdd, unsigned char LowAdd, unsigned char *rdptr, unsigned char length )

{

  IdleI2C();                      // ensure module is idle

  StartI2C();                     // initiate START condition

  while ( SSPCON2bits.SEN );      // wait until start condition is over 

  WriteI2C( ControlByte );        // write 1 byte 

  IdleI2C();                      // ensure module is idle

  WriteI2C( HighAdd );            // WRITE word address to EEPROM

  IdleI2C();                      // ensure module is idle

  WriteI2C( LowAdd );             // write HighAdd byte to EEPROM

  IdleI2C();                      // ensure module is idle

  RestartI2C();                   // generate I2C bus restart condition

  while ( SSPCON2bits.RSEN );     // wait until re-start condition is over 

  WriteI2C( ControlByte | 0x01 ); // WRITE 1 byte - R/W bit should be 1 for read

  IdleI2C();                      // ensure module is idle

  getsI2C( rdptr, length );       // read in multiple bytes

  NotAckI2C();                    // send not ACK condition

  while ( SSPCON2bits.ACKEN );    // wait until ACK sequence is over 

  StopI2C();                      // send STOP condition

  while ( SSPCON2bits.PEN );      // wait until stop condition is over 

  return ( 0 );                   // return with no error

}

*/

/********************************************************************

*     Function Name:    putstringI2C                                *

*     Return Value:     error condition status                      *

*     Parameters:       address of write string storage location    *

*     Description:      This routine writes a string to the I2C bus,*

*                       until a null character is reached. If Master*

*                       function putcI2C is called. When trans-     *

*                       mission is complete then test for ack-      *

*                       nowledge bit. If Slave transmitter wait for *

*                       null character or not ACK received from bus *

*                       device.                                     *

********************************************************************/

unsigned char putstringI2C( unsigned char *wrptr )

{

unsigned char x;

  for (x = 0; x < PageSize; x++ ) // transmit data until PageSize  

  {

    if ( SSPCON1bits.SSPM3 )      // if Master transmitter then execute the following

    {

      if ( putcI2C ( *wrptr ) )   // write 1 byte

      {

        return ( -3 );            // return with write collision error

      }

      IdleI2C();                  // test for idle condition

      if ( SSPCON2bits.ACKSTAT )  // test received ack bit state

      {

        return ( -2 );            // bus device responded with  NOT ACK

      }                           // terminateputstringI2C() function

    }

    else                          // else Slave transmitter

    {

      PIR1bits.SSPIF = 0;         // reset SSPIF bit

      SSPBUF = *wrptr;            // load SSPBUF with new data

      SSPCON1bits.CKP = 1;        // release clock line 

      while ( !PIR1bits.SSPIF );  // wait until ninth clock pulse received

      if ( ( !SSPSTATbits.R_W ) && ( !SSPSTATbits.BF ) )// if R/W=0 and BF=0, NOT ACK was received

      {

        return ( -2 );            // terminateputstringI2C() function

      }

    }

  wrptr ++;                       // increment pointer

  }                               // continue data writes until null character

  return ( 0 );

}