#include <msp430.h>


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

    // Configure GPIO
    P6DIR |= BIT6;                                // P1.0 output
    P6OUT |= BIT6;                                // P1.0 high

    P4OUT |= BIT1;                          // Configure P1.3 as pulled-up
    P4REN |= BIT1;                          // P1.3 pull-up register enable
    P4IES |= BIT1;                          // P1.3 Hi/Low edge
    P4IE |= BIT1;                           // P1.3 interrupt enabled

    // Disable the GPIO power-on default high-impedance mode to activate
    // previously configured port settings
    PM5CTL0 &= ~LOCKLPM5;
    P4IFG &= ~BIT1;                         // P1.3 IFG cleared

    TB0CCTL0 |= CCIE;                             // TBCCR0 interrupt enabled

    TB0CCR0 = 25600;
    TB0CTL = TBSSEL__ACLK | MC__UP;             // ACLK, UP mode

    __bis_SR_register(LPM0_bits | GIE);          // Enter LPM0 w/ interrupt
    __no_operation();                            // For debug
}

// Timer0_B0 interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = TIMER0_B0_VECTOR
__interrupt void Timer0_B0_ISR (void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(TIMER0_B0_VECTOR))) Timer0_B0_ISR (void)
#else
#error Compiler not supported!
#endif
{
  P6OUT ^= BIT6;
}