Making PWM from 2 Analog input in MSP430G2231?
You are not waiting for the ADC to finish the conversions. 
You would have to do something like this:

 for (;;)
{
  ADC10CTL0 &amp;= ~ENC;

  while (ADC10CTL1 &amp; BUSY);                 // Wait if ADC10 core is active
    ADC10SA = 0x200;                        // Data buffer start
    P1OUT |= 0x01;                          // Set P1.0 LED on
    ADC10CTL0 |= ENC + ADC10SC;             // Sampling and conversion start
    __bis_SR_register(CPUOFF + GIE);        // LPM0, ADC10_ISR will force exit
    P1OUT &amp;= ~0x01;                         // Clear P1.0 LED off
 }


}

You should read the user guide - chapter 20 (I think) ADC10 and look at the code examples on ADC10 with DTC