MSP430FG6626: CTSD16 Calibration

Hi,

I'm trying to calibrate the CTSD16 A/D by using the internal DAC connection but I'm not able to get a reading that corresponds to the DAC output.  I'm able to use both the A/D and DAC independently and can monitor the Veref+, internal temperature sensor, and AVcc through the A/D but every time I try to read the DAC I get a reading of approximately 32768 regardless of what the DAC output is set to.  Are there any special considerations for reading the DAC other than setting the channel to CTSD16_INPUT_CH18? 

Thanks,

Justin

void initialize_dac()
{
	//Set the reference to external, setup the amplifier to medium speed and current
	DAC12_0CTL0 = DAC12SREF_3 | DAC12AMP_5  | DAC12OPS;

	//Set Gain to 2x reference (If DAC12OG is on and DAC12IR is off gain is 2x)
	DAC12_0CTL1 = DAC12OG;
       __delay_cycles(1000);
      //Clear the data register
      DAC12_0DAT = 0;

     //Run the internal calibration routine on the DAC
     DAC12_0CALCTL = DAC12PW;					//Set the password and disable the cal register lock bits
     DAC12_0CTL0 |= DAC12CALON;					//Start the calibration
     while( DAC12_0CTL0 & DAC12CALON );			//Wait for calibration to finish
     DAC12_0CALCTL = ( DAC12PW | DAC12LOCK );	//Enable the cal register lock bits

     DAC12_0CTL0 |= DAC12ENC;
}

#define CALSAMPLES 10
void adcOffsetCal()
{
	// enable the external reference block for CTDS16
	CTSD16CTL &= ~CTSD16OFFG;
	//External Reference IO Pin must be set to alternative function
	P5SEL |= BIT0;

	// enable P6SEL.0 to gate reference for conversions on A0-A3
	// P4SEL.6 and P4SEL.1 for A4 and A5
	P6SEL |= BIT3 + BIT2 + BIT1 + BIT0;
	P4SEL |= BIT6 + BIT1;	

        DAC12_0DAT = 1000;
	// Initialize CTSD16 using external reference and internal resistor for clock
	CTSD16_init(CTSD16_BASE, CTSD16_RTR_INPUT_CHARGEPUMP_BURST_REQUEST_ENABLE, CTSD16_REF_EXTERNAL);


	CTSD16_initConverterAdvancedParam convAdvParam = {0};
	convAdvParam.converter = CTSD16_CONVERTER_0;
	convAdvParam.conversionMode = CTSD16_SINGLE_MODE;
	convAdvParam.groupEnable = CTSD16_NOT_GROUPED;
	convAdvParam.inputChannel = CTSD16_INPUT_CH18;
	convAdvParam.dataFormat = CTSD16_DATA_FORMAT_BINARY;
	convAdvParam.railToRailInput = CTSD16_RTR_INPUT_ENABLE;
	convAdvParam.interruptDelay = CTSD16_FOURTH_SAMPLE_INTERRUPT;
	convAdvParam.oversampleRatio = CTSD16_OVERSAMPLE_256;  // Required for 16 bit samples
	convAdvParam.gain = CTSD16_GAIN_1;
	CTSD16_initConverterAdvanced(CTSD16_BASE, &convAdvParam);

	uint16_t dummy[CALSAMPLES];
	uint32_t dummyAvg = 0;
	int16_t i = 0;

	for( i = 0; i < CALSAMPLES; i++ ) {
		// Clear converter 0 interrupt flags
		CTSD16_clearInterrupt(CTSD16_BASE, CTSD16_CONVERTER_0, CTSD16_CONVERTER_INTERRUPT | CTSD16_CONVERTER_OVERFLOW_INTERRUPT);
                CTSD16_startConverterConversion(CTSD16_BASE, CTSD16_CONVERTER_0);
		while(!CTSD16_getInterruptStatus(CTSD16_BASE, CTSD16_CONVERTER_0, CTSD16_CONVERTER_INTERRUPT));
		dummy[i] = CTSD16_getResults(CTSD16_BASE, CTSD16_CONVERTER_0) >> 8;
		dummyAvg += dummy[i];
	}
	dummyAvg /= CALSAMPLES;
}