push_button.c

#include <msp430.h>
#include <legacymsp430.h>

#define LED0    BIT0
#define LED1    BIT6
#define LED_DIR P1DIR
#define LED_OUT P1OUT
#define BUTTON  BIT3

volatile unsigned int blink = 1;

void initLEDs(void) {
    LED_DIR |= LED0 + LED1;
    // LED_OUT &= ~(LED0 + LED1);
    LED_OUT |= (LED0 + LED1);
}


int main(void) {
    WDTCTL = WDTPW + WDTHOLD;
    initLEDs();
    P1IE |= BUTTON; // Set button to trigger interrupt (I think)

    WRITE_SR(GIE);  //Enable global interrupts

    while (1) {
        if (blink) {
            LED_OUT ^= (LED0 + LED1);
            __delay_cycles(100000); // SW delay of 100000 cycles at 1Mhz
        }
    }

    return 0;
}

interrupt(PORT1_VECTOR) PORT1_ISR(void)
{
  // LED_OUT ^= (LED0 + LED1);
     blink ^= 0x01;
     LED_OUT &= ~(LED0 + LED1);
     P1IFG &= ~BUTTON; // P1.3 IFG cleared
}