#include <msp430g2553.h>

#define LED0 0x01
#define LED1 0x40
#define BTN1 0x08

#define BLINK_STATE 0x01

unsigned volatile int i;
unsigned int state = BLINK_STATE;

int main(void)
{
    WDTCTL = WDTPW + WDTHOLD;
    P1DIR |= LED0 + LED1; // Set LED0 and LED1 to OUTPUT
    P1DIR &= ~(BTN1); // BTN1 to INPUT state

    // Switch LED0 on, LED1 off
    P1OUT |= LED0;
    P1OUT &= ~(LED1);
    P1REN |= BTN1;

    while(1) {
        if(!(P1IN & BTN1)) // Button is pressed
            state ^= BLINK_STATE;

        if(state & BLINK_STATE)
            P1OUT ^= LED0 | LED1;
        for(i=0; i<50000; i++);
    }

    return 0;
}