MSP430 Timer_A - scale of a register - c

Question

programming on MSP430 in CCS
Using Timer_A, ACLK and his interrupt to blink LED(just blinking now- same long time torned off- same time turned on).
This code blink led with 2 sec delay. There is problem that register TA1CCR0 can be max 0xFFFF= 65535 (2 sec for ACLK). And for my application(blinking LED is only exapmle) I will need scale from 1 sec to 999 sec. (row 6-7 in code). How can I do that? Is it possible?
#include <msp430.h>
#include <msp430f6736.h>
void CfgTA(unsigned long delayCycles)
{
int t2=2; // must be variable from 1 to 999
t2=delayCycles*t2;
TA1CCTL0 |= CCIE; //Enable Interrupts on Timer
TA1CCR0 = t2-1; //Number of cycles in the timer
TA1CTL |= TASSEL_1 | MC_1; //ACLK , UP mode
}
void ledblink()
{
//LED config
P4DIR |= BIT6;
P4OUT &= ~BIT6;
CfgTA(32768); //Timer configuration to blink every 1 sec
while (1)
{
_bis_SR_register(LPM3_bits + GIE); //Enter Low Power Mode 3 with interrupts
}
}
#pragma vector=TIMER1_A0_VECTOR
__interrupt void Timer_A0(void)
{
P4OUT ^= BIT6; // Swapping on/off LED
}
int main(void) {
WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer
ledblink();
return 0;
}

Answer 1

how to count seconds on a 1 second interrupt.
1) initialize interrupt to occur once each second and reload its' timer/counter register
2) set global variable to number of seconds to delay:
int delaySeconds = 10;
3) inside the interrupt function
static int count =0;
count++;
if( count >= delaySeconds )
{
count = 0;
P4OUT ^= BIT6; // Swapping on/off LED
}
I think the interrupt function, before exiting, also needs to clear the time1 interrupt pending flag

Answer 2

On your MSP430, you can slow down ACLK with the DIVA field in the UCSCTL5 register, and you can further divide down the timer's clock input with the ID and IDEX fields in the TAxCTL and TAxEX0 registers.
With the timer input divided down to 16 Hz, you would be able to count for up to 4096 seconds.