#include <msp430g2553.h>
int a;

void main(void)
{
    WDTCTL = WDTPW + WDTHOLD;
    TA0CTL = TASSEL_2 + MC_1;                       //TASSEL_2 selects SMCLK as the clock source, and MC_1 tells it to count up to the value in TA0CCR0.

    P1DIR = BIT6;
    P1SEL = BIT6;                                   //select LED as PWM output
    P1REN = BIT3;
    P1OUT = BIT3;
    P1IE |= BIT3;
    P1IES |= BIT3;
    P1IFG = 0x00;

    //Timer interrupt
    CCTL0 = CCIE;
    CCR0 = 10000;

    _enable_interrupts();

    TA0CCR0 = 1000;
    TA0CCTL1 = OUTMOD_7;
    TACCR1 = 0;
    //__bis_SR_register(LPM0_bits);                   //Switch to low power mode 0.


}

#pragma vector = TIMER0_A0_VECTOR
__interrupt void fade(void) {
    if(TACCR1 == TACCR0) a = -1;
    else if(TACCR1 == 0) a = 1;
    TACCR1+=a;
}