dac-opamp-adc

Other Parts Discussed in Thread: MSP430FG4618

i'm using the msp430fg4618 experimenters board....i gave 00 to my DAC_DAT0 register....connected it to the internal opamp which acts as a voltage follower circuit....n the output of the opamp is given to the internal ADC12...

however the reading in the ADCMEM register is not zero....heres my prog:

#include "msp430fg4618.h"

void DAC12Init(void)
{

  DAC12_0DAT= 0x00;
  ADC12CTL0 = REF2_5V + REFON;                
 
  DAC12_0CTL = DAC12IR | DAC12AMP_5 | DAC12ENC;
 
}

void ADC12Init(void)
{
  ADC12CTL0 &= ~ENC;
  ADC12CTL0 |= SHT0_4 | ADC12ON;
  ADC12CTL1 = CSTARTADD_0 ;
  ADC12MCTL0 = INCH_1 | SREF_1;
  ADC12CTL0 |= ENC;                         
  ADC12CTL0 |= ADC12SC;                     
  ADC12IE |= BIT1;                         
}  

void OPInit()
{
  OA0CTL1 |= OAFC_4 | OAFBR_0;
  OA0CTL0 |= OAP_2 | OAPM_3 | OAADC1;
      
}


void main (void)
{
  WDTCTL = WDTPW | WDTHOLD;
 
 
  DAC12Init();

 
  ADC12Init();
 
  OPInit(); 

  TACTL = TASSEL_1 + MC_2 + TACLR + TAIE;

  _BIS_SR(GIE);
}

#pragma vector=ADC12_VECTOR
__interrupt void ADC_ISR(void)
{
   int x;
    x = ADC12MEM1;       
    ADC12CTL0 |= ADC12SC;
}

#pragma vector=TIMERA1_VECTOR
__interrupt void TimerA_ISR (void)
{
    ADC12CTL0 &=  ~ADC12SC;
    TACTL &= ~TAIFG;
}