basic timer not working

i have msp430fg4618/2013 experimenters board i dump fo;;owing code but execution never enter in basic timer isr routine dose it mean aclk not working because sample lcd programme is also not working

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#include "msp430xG46x.h"

void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
FLL_CTL0 |= XCAP18PF; // Set load cap for 32k xtal
P1DIR |= 0x01; // Set P1.0 as output
BTCTL = BTDIV + BT_fCLK2_DIV16; // ACLK/(256*16)
IE2 |= BTIE; // Enable BT interrupt

_BIS_SR(LPM3_bits + GIE); // Enter LPM3, enable interrupts




}

/// Basic Timer Interrupt Service Routine
#pragma vector=BASICTIMER_VECTOR
__interrupt void basic_timer_ISR(void)
{
P1OUT ^= 0x01; // Toggle P1.0
}

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