MSP430 - use an interrupt to set the LEDs on and off using the button

InterruptMSP430.c

//
//  main.c
//  
//  Use an interrupt to set two LEDs on the MSP430 on and off
//  Created by David Roberts on 06/07/2011.
//

#include <io.h>
#include <signal.h>

#define BUTTON BIT3
#define LED1 BIT0
#define LED2 BIT6

int main (void)
{	
    // disable the watchdog timer
    WDTCTL = WDTPW + WDTHOLD;
    
    // interrupt from high to low
    P1IES |= BUTTON;
    // clear the interrupt flag
    P1IFG &= ~BUTTON;
    // enable interrupt on BIT3
    P1IE |= BUTTON;
    
    P1OUT = 0;
    P1OUT |= LED2;
    // set bit0, bit6 as output
    P1DIR |= LED1;
    P1DIR |= LED2;
    
    // enable interrupts
    _BIS_SR(GIE);
    
    while(1);
    return 0;
}


// interrupt for PORT1 
interrupt(PORT1_VECTOR) p1_isr(void) {
    // check if BIT3 button has set flag
    switch (P1IFG & BUTTON) {
        case BUTTON:
            P1IFG = P1IFG & ~BUTTON;
            
            // flip the LED output
            P1OUT ^= LED1;
            P1OUT ^= LED2;
            break;
        default:
            break;
    }
    
    return;
}