Msp430 hcsr04 interrupt

#include <msp430.h>

int main()
{
    int echo_pulse_duration;      // time in us
    int distance_cm;

    // Disable watchdog timer
    WDTCTL = WDTPW + WDTHOLD;

    // Make P1.0 a digital output for the LED and P1.6
    // a digital output for the sensor trigger pulses
    P1DIR = BIT1+BIT6;
    P1IN = BIT2;

    // Set up Timer_A1: SMCLK clock, input divider=1,
    // "continuous" mode. It counts from 0 to 65535,
    // incrementing once per clock cycle (i.e. every 1us).
    TA1CTL = TASSEL_2 + ID_0 + MC_2;

    // Now just monitor distance sensor
    while(1)
    {

        // Send a 20us trigger pulse
        P1OUT |= BIT1;                // trigger high
        __delay_cycles(20);           // 20us delay
        P1OUT &= ~BIT1;               // trigger low

        // Measure duration of echo pulse
        while ((P1IN & BIT2) == 0);   // Wait for start of echo pulse
        TA1R = 0;                     // Reset timer at start of pulse
        while ((P1IN & BIT2) > 0);    // Wait for end of echo pulse
        echo_pulse_duration = TA1R;   // Current timer value is pulse length
        distance_cm = 0.017 * echo_pulse_duration; // Convert from us to cm

        if (distance_cm < 50) P1OUT |= BIT6; // LED on
        else P1OUT &= ~BIT6;                 // LED off
    }
}

So I am trying to make projects with hc-sr04. This code above works but I want to make it with interrupt and see distance in serial terminal screen. Can anyone help me?