#include <msp430g2152.h>					
unsigned int new_cap=0;						
unsigned int old_cap=0;						
unsigned int cap_diff=0;					
void main(void)
{
    WDTCTL = WDTPW + WDTHOLD;                   		// Stop WDT
    BCSCTL1 = CALBC1_16MHZ;                    // Set Oscillator range
  DCOCTL = CALDCO_16MHZ; 
    P1SEL |= BIT2;                              		// Port 1.2/TACCR1 - Input                 
   P1DIR=0xF0;				        		// P1.4, P1.5, P1.6, P1.7 as a output
    P1OUT=0x00; 						// Initially reset port1                     
  P1OUT |=0x10;						// P1.4 High for Green status LED 
    TACTL = TASSEL_2 +MC_2;          				// SMCLK = 1 Mhz, continuous mode
    TACCTL1 = CM_1+CCIS_0+SCS+CAP+CCIE; 			// capture on rising edge & falling edge, Timer A select, Sync., capture mode, Enable timer interrupt
        
    __bis_SR_register(LPM0_bits + GIE);         		// LPM0 mode
}    

// Timer A1 interrupt service routine

#pragma vector = TIMER0_A1_VECTOR
__interrupt void TA1_ISR(void)
{
 switch( TAIV )                                 // Efficient switch-implementation
  {
    case 2:                                     // CCR1 capture value
      new_cap = TACCR1;
    cap_diff = new_cap - old_cap;		
     old_cap = new_cap;                          // move current value 
   break;                 
  }
}