//::::::::::::::::::::::::::::::::::::::::::::::::::::::
// TWI interrupt routine
//::::::::::::::::::::::::::::::::::::::::::::::::::::::
#pragma vector=TWI_vect
__interrupt void TWI_interrupt( void )
{
  switch(TWSR & 0xF8) // Read result code and switch to next action
  {
  //---- Start and TRANSMIT conditions -------
  case 0x08:
  // A START condition has been transmitted
  case 0x10:
    // A repated START condition has been transmitted
	if(twi.err_cnt < TWI_MAX_ERR)
	{
      twi.err_cnt++;
      TWDR = twi.dsel;                                  // Send (Resend) Selector and RW bit
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWINT);
	}
      else
	  {
        twi.err_code = TWI_ERR;
		twi.flags |= (1 << TWI_FLAG_READY);               // Signal end of TWI activity
        TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTO)|(1 << TWINT);
	  }
	break;

  case 0x20:
  // Salve Selector+WR, Not ACK
  case 0x48:
	// Slave Selector+RD, Not Ack
	// Предполагается при неготовности при продолжении цикла записи
	// посылается старт заново
	if(twi.err_cnt < TWI_MAX_ERR)
	{
      twi.err_cnt++;
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTA)|(1 << TWINT);
	}
      else
	  {
        twi.err_code = TWI_ERR;
		twi.flags |= (1<<TWI_FLAG_READY);	            // Signal end of TWI activity
        TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTO)|(1 << TWINT);
	  }
	break;

  case 0x18:
	// Slave Selector+WR has been transmitted, ACK
   	twi.err_cnt = 0;
    TWDR = *(twi.ptr_to_data + twi.bcnt); 				// Write to TX register  first DATA byte
    twi.bcnt++;
    TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWINT);
	break;

  case 0x28:
	// Data byte has been transmitted; ACK has been received

	if(twi.bcnt < twi.bsize)							// Data sent, Ack
	{
      TWDR = *(twi.ptr_to_data + twi.bcnt);				// Write data to TX register
      twi.bcnt++;
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWINT);
	} 
	  else
	  {
        twi.flags |= (1<<TWI_FLAG_READY);	// Signal end of TWI activity
        TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTO)|(1 << TWINT);
      }
	twi.err_cnt = 0;
	break;

  case 0x30:
	// Data sent, NOT Ack
	if(twi.err_cnt < TWI_MAX_ERR)
	{
      TWDR = *(twi.ptr_to_data + twi.bcnt);		// Resent Data
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWINT);
	}
	  else
	  {
	    twi.err_code = TWI_ERR;
		twi.flags |= (1<<TWI_FLAG_READY); 	// Signal end of TWI activity
        TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTO)|(1 << TWINT);
	  }
	break;

//------------------------------------------
  case 0x38:
  // Arbitration Lost
	if(twi.err_cnt < TWI_MAX_ERR)
	{
      twi.err_cnt++;
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTA)|(1 << TWINT);
	}
      else
	  {
	    twi.err_code = TWI_ERR;
		twi.flags |= (1<<TWI_FLAG_READY); 	// Signal end of TWI activity
        TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTO)|(1 << TWINT);
	  }
	break;

  //---- RECEIVE conditions ------------------
  case 0x40:
	// Slave Selector+RD, ACK
    twi.err_cnt = 0;
    TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWEA)|(1 << TWINT);
	break;

  case 0x50:
	// Data Received, ACK has been returned
	if(twi.bcnt < twi.bsize)
	{
      *(twi.ptr_to_data + twi.bcnt) = TWDR;
   	  twi.bcnt++;
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWEA)|(1 << TWINT);
    }
	  else
	  {
  	    TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWINT);
	  }
	twi.err_cnt = 0;
	break;

  case 0x58:
	// Data Received, Not Ack
	if(twi.bcnt < twi.bsize)
    {
      twi.err_code = TWI_ERR;
      twi.flags |= (1 << TWI_FLAG_READY); 	// Signal end of TWI activity
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTO)|(1 << TWINT);
    }
      else
      {
        twi.flags |= (1 << TWI_FLAG_READY);		// Signal end of TWI activity
        TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTO)|(1 << TWINT);
      }
	break;

  default:
    // Unknown code
	if(twi.err_cnt < TWI_MAX_ERR)
	{
      twi.err_cnt++;
      TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWSTA)|(1 << TWINT);
	}
  	  else
	  {
 		twi.err_code = TWI_ERR;
		twi.flags |= (1 << TWI_FLAG_READY); // Signal end of TWI activity
        TWCR = (1 << TWEN)|(1 << TWIE)|(1 << TWINT);
	  }
  }
}