Unwanted Spike in PWM Singal

Hi All,

Could you please tell me why am I getting these spikes in the image below?

Here is the test code:

#include  <msp430g2553.h>

const unsigned int halfcycle[51] = {100, 108, 115, 122, 129, 135, 141, 146, 151, 154, 157, 159, 160, 160, 159, 157, 154, 151, 146, 141, 135, 129, 122, 115, 108, 100, 92, 85, 78, 71, 65, 59, 54, 49, 46, 43, 41, 40, 40, 41, 43, 46, 49, 54, 59, 65, 71, 78, 85, 92 };

signed int index = -1;
unsigned int comp = 0;


void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT

  //Calibrate DCO for 1MHz operation
  BCSCTL1 = CALBC1_1MHZ;
  DCOCTL = CALDCO_1MHZ;

  P2DIR |= BIT1 + BIT2;                            
  P2SEL |= BIT1;
  P2SEL &= ~(BIT2);

  P2OUT &= ~(BIT1+BIT2);



  TA1CCR0 = 200 - 1;                               
  TA1CCTL0 = CCIE;									// CCR0 interrupt
  TA1CCTL1 = OUTMOD_2 + CCIE;                         
  TA1CTL = TASSEL_2 + MC_3 + TACLR;                  // SMCLK, up-down mode

  _BIS_SR(LPM0_bits + GIE);                       // Enter LPM0

}




#pragma vector=TIMER1_A1_VECTOR						// ISR for CCR1 and CCR2 interrupts
__interrupt void Timer_A1 (void)
{
	switch (__even_in_range(TA1IV, 10))
	{
		case 0:											// no interrupt is pending
		{
			break;
		}
		case 2:											// CCR1
		{

			TA1CCR1 = halfcycle [index] - 1;
			break;
		}
		case 4:											// CCR2
		{
			break;
		}
		case 10:										// TA1IFG
		{
			break;
		}

	}

}


#pragma vector=TIMER1_A0_VECTOR						// ISR for CCR0
__interrupt void Timer_A0 (void)
{
	 index = index + 1;

	  if(index == 25)
	 {
		 index = 0;
		 P2SEL ^= (BIT1 + BIT2);

	 }
}