CCS/MSP430G2211: When MSP430 had gone into low power mode(LPM3), we wakeup it by I/O interrupt, and initialized Timer, but Timer interrupt could not run occasionally.

Tool/software: Code Composer Studio

platform: MSP430G2211, CCS6.2

Question: When MSP430 had gone into low power mode(LPM3), we wakeup it by I/O interrupt, and initialized Timer, but Timer interrupt could not run occasionally.

Codes:

void System_Initial_Interrupt(void)
{

TA0CCTL0 |= CCIE; // TBCCR0 interrupt enabled
TA0CCR0 = 1000;

TA0CTL = TASSEL_2 | MC_1; // SMCLK, UP mode

// WDTCTL = WDT_ARST_1000;
}



#pragma vector=PORT1_VECTOR
__interrupt
void Port_1(void)
{

__bic_SR_register_on_exit(LPM3_bits);

Feedback_Signal_Pin_Set();
TA0CTL =MC_0 | TACLR;


System_Initial_Interrupt();


LowPower=0;

//TA0CCR0 = 1000;
P1IFG &= ~BIT3;
P1IE &= ~BIT3;


}