MSP430 Launchpad Problem

#include <msp430g2253.h>

int main(void)  //Main program

{

  WDTCTL = WDTPW + WDTHOLD;  //Stop Watchdogtimer

  P1DIR |= BIT0;  //Set P1.0 to output and P1.3 to input direction

  P1OUT &= ~BIT0;  //Set P1.0 to Off

  P1IE |= BIT3;  //P1.3 interrupt enabled

  P1IFG &= ~BIT3;  //P1.3 interrupt flag cleared

  __bis_SR_register(GIE);    //Enable all interrupts

  while(1)

  {

  }

}

#pragma vector=PORT1_VECTOR

__interrupt void Port_1(void)

{

  P1OUT ^= BIT0;  //Toggle P1.0

  P1IFG &= ~BIT3;  //P1.3 interrupt flag cleared

}