Dave,
this piece of code works for me.


void __INT(void)
{
        save_context;
        if(PIR1.SSPIF)
        {
                PIR1.SSPIF = FALSE;             // Clear I2C interrupt flag
                I2C_InterruptServiceRoutine();  // decode I2C message
Transmit or receive
        }
        restore_context;
        return;
}



void I2C_Initialize(void)
{
        SSPCON= 0x3e;
        PIE1.SSPIE = TRUE;
        SSPADD = I2C_SLAVE_ADDRESS;
        TRISC.3 = HIGH;
        TRISC.4 = HIGH;
        PIR1.SSPIF = FALSE
        INTCON.PEIE = TRUE
        ReceiveIndex = 0;
        I2cTransmitBusy = FALSE;
        TransmitIndex = 0;      
 }


void I2C_InterruptServiceRoutine(void)
{
        if (SSPSTAT.BF) //buffer full
        {
                I2C_ReceiveBuffer[ReceiveIndex] = SSPBUF;
                ReceiveIndex++;
        }
        if (SSPSTAT.P)  // stop detected
        {
                TransmitIndex = 0;
                ReceiveIndex = 0;
                I2C_ReceiveInterpreterTask();
                I2cTransmitBusy = FALSE;
        }
        if(SSPSTAT.R)   // restart detected
        {
                I2C_TransmitInterpreterTask();
        }
}

void I2C_ReceiveInterpreterTask(void)
{
        switch(I2C_ReceiveBuffer[1])
        {
                case LAS_CMD_START_LASEROUTPUT:
                        LAS_SetSelectedLaser(I2C_ReceiveBuffer[2]);
                        DBS_LaserMode = LAS_MAIN_ON_STATE;
                break;

                case .....
                break;
        }
}

void I2C_TransmitInterpreterTask(void)
{
        switch(I2C_ReceiveBuffer[1])
        {
                case LAS_CMD_READ_STATUS:
                        if (I2cTransmitBusy == FALSE)
                        {
                                I2cTransmitBusy = TRUE;
                                TransmitIndex = 0;

                                I2C_TransmitBuffer[0] = DBS_LaserMode;

                                I2C_TransmitBuffer[1] = DBS_LaserCurrent;
                                I2C_TransmitBuffer[2] = DBS_LaserCurrent;
                                
                                I2C_TransmitBuffer[3] =
BS_LaserFrequencyHB;                            
                                I2C_TransmitBuffer[4] =
DBS_LaserFrequencyLB;                           
                                I2C_TransmitBuffer[5] = DBS_LaserFlags;    
        
                        }

                        SSPBUF = I2C_TransmitBuffer[TransmitIndex++];
                        SSPCON.4 = TRUE;
                break;

                case .....
                break;
        }
}



______________________________
Frank Temmerman
Gymna R&D

EMAIL: gymna@compuserve.com
TEL: +32 (0)89 510 535
FAX: +32 (0)89 510 511
______________________________