Problems with Timer_A Counter with external clock source TACLK in MSP430

Hi,

I'm trying implement counter using Timer_A in msp430fg4618 by giving external clock source TACLK. But somehow it is not working.

Please refer below code snippet.

/******************************************************

void TimerA_Init(int delay)
{
   TACTL = (TASSEL_0 | ID_0 | TACLR);     //Use External clock TACLK, divide by 8 and reset TAR
   P1SEL |= 0x20;                         //Enabling Portpin P1.5(TACLK) for clock i/p
   TACCTL0 = CCIE;                        //Enable the Capture/Compare Interrupt
   TACCR0 = 100;                          //
   TACTL |= MC_1;                         //Set it to run in 'up mode' and thus start the counter
} 

#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{ 
  //Some Logic and Timer Reset
}

/*****************************************************/

I have applied 10kHz 3Vpp Square wave signal to the TACLK(P1.5) using function generator.

With above setup I am not getting Timer_A interrupt. I am not able to understand whether above set up is working or not.

Please suggest what is going wrong.