MSP430 Launchpad TimerA Interrupt Example

[nickelflippr]

Thought I would post some code for those Launchpad owners out there using CCS. I could become a convert,........ once I get the C syntax down. Actually using the debugger now, because I'm getting nailed left and right on stupid mistakes.

I was needing to put my chip to sleep, and wake up every 10 minutes or so to check on some inputs. So here is the code that comes within a handful of seconds of doing so.

//A rough 10 minute timer example using the MSP430_Launchpad
//Utilizes TIMERA0 interrupt, and the low power VLOCLK (12khz)
//CCS v4.1.3.xx

#include "msp430g2211.h"
#define LED0 BIT0
unsigned char count = 0;

void main(void)
{
    WDTCTL = WDTPW + WDTHOLD;		// Stop WDT
    P1DIR |= 0xFF;			//All outputs
    P1OUT = 0;
    BCSCTL3 = LFXT1S1;			//Select VLOCLK for ACLCK (i.e. 12khz intosc)
    P1OUT |= LED0;
    TACCTL0 = OUTMOD_2 + CCIE;		// TACCR0 interrupt enabled
    TACCR0 = 32768;	//Compare to Timer_A register (approx. 25 sec for VLOCLK & 1/8 divider)
    TACTL = TASSEL_1 + ID1 + ID0 + MC_1;    // ACLCK, 1/8 DIVIDER, upmode to TCCR0 value

for(;;)
{
  __bis_SR_register(LPM3_bits + GIE);    //Enter LPM3 w/interrupt
  __no_operation();		// For debugger, executes next instruction just like a PIC
}
}

#pragma vector=TIMERA0_VECTOR		// Timer A0 interrupt service routine
__interrupt void Timer_A (void)
{
	count += 1;
	TACCR0 = 32768;			// reset TACCR0 register
	if (count==24){			//24 * 25sec is approx. 10 minutes
		P1OUT ^= LED0;		//Toggle LED
		count = 0;
	}
}

 

[kiranvarma]

Why don't you place the LPM instruction outside the for loop!
no need to execute repeatedly the instruction in infinite loop.