Low power MSP430F2618 not able to reduce current below 900uA

Hi

I was using the Evaluation module for MSP430F2618

My application needs CPU to be active and must have low power. For this purpose i tried out a small program to run uC at a low clock rate

I modified one example code of MSP430F2618

#include  <msp430x26x.h>

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  BCSCTL3 |= LFXT1S1 ;
  BCSCTL2 |= (SELM1+SELM0+SELS);
 
  ADC12CTL0 = SHT0_2 + ADC12ON;             // Set sampling time, turn on ADC12
  ADC12CTL1 = SHP+ ADC12SSEL1;                          // Use sampling timer
  ADC12IE = 0x01;                           // Enable interrupt
  ADC12CTL0 |= ENC;                         // Conversion enabled
  P6DIR &= 0x01;                            // P6.0, i/p
  P6SEL |= 0x01;                            // P6.0-ADC option select
  //P1DIR |= 0x01;                            // P1.0 output-LED

  for (;;)
  {
    ADC12CTL0 |= ADC12SC;                   // Start convn, software controlled
    _BIS_SR(CPUOFF + GIE);                  // LPM0, ADC12_ISR will force exit
  }
}

// ADC12 interrupt service routine
#pragma vector=ADC12_VECTOR
__interrupt void ADC12_ISR (void)
{
    //if (ADC12MEM0 < 0x7FF)
      //P1OUT &= ~0x01;                       // Clear P1.0 LED off
    //else
      //P1OUT |= 0x01;                        // Set P1.0 LED on
    _BIC_SR_IRQ(CPUOFF);                    // Clear CPUOFF bit from 0(SR)
}

I am always getting a current consumption of 900uA @ 3V

This is way above the CPU limits. Also when I put break point in the program the device current reduces to 200uA

Please let me know how to make CPU work in lower clock rate