MSP430F4784: one second delay using Timer

sai devaraj m

Part Number: MSP430F4784

Hi,

I'm currently using MSP430F4784 controller.

In this I want to make a N number of delays (maximum 10sec delay only).

I'm able to achieve the required delay I want but while the program is running the execution stays at particular while loop in delayMS function which I included below.

But this is happening abruptly and continues for 3 to 4 times in a sequence. what could be causing this issue.

Please kindly help me with this.

volatile unsigned int k=0;
volatile unsigned int h=0;
volatile unsigned int l=0;

void tim(void)
{
    TACTL |= MC_0;
     TACTL |= TACLR;
      TACTL = TASSEL_1 + ID_0;                  // SMCLK, continuous mode
      TA0CCTL0 = CCIE;
      TA0CCR0  = 32768;

}

void delayMS(int x)
{
    TACTL |= MC_2;
    k=0;
    h= x;
    while(!l);

    l=0;
    TACTL |= MC_0;
}


int main(void)
{
	WDTCTL = WDTPW | WDTHOLD;	// stop watchdog timer
	P9DIR |= BIT5;

	tim();
	
	while(1)
	{
	    P9OUT ^= BIT5;
	    delayMS(2);
	  }
	 }
	 
#pragma vector = TIMER0_A0_VECTOR
__interrupt void Timer_A0( void )
{
    TA0CCTL0 &= ~CCIFG;
                        
  k++;
    if(k == h)
    {
       k=0;
       l=1;
    }
}

over 3 years ago

0 Xiaodong LI over 3 years ago

TI__Mastermind 23295 points

On the delay function using Timer A0, it is related with timer clock source and timer settings.

Could you please test and refer to the msp430x47xx_ta_01.c code on MSP430F47x3, MSP430F47x4 Code Examples (Rev. I)

Thanks!

0 sai devaraj m over 3 years ago in reply to Xiaodong LI

Intellectual 340 points

Delay is working fine. whatever delay I required I can get. But while running, in some places where delay is called it gets struck in while(!l); in delayMS function. It happens suddenly I can't find out what causes this issue. Does timer behaves like this?. Is this common in MSP430 MCUs?. How to resolve this?.

0 Bruce McKenney over 3 years ago

Guru 100745 points

> TACTL |= MC_0;

This doesn't stop the timer, since MC_0==0. Try instead:

> TACTL &= ~MC_3; // Set MC=0 (stopped)

--------------------

> TACTL |= MC_2;

This sets Continuous mode, and doesn't clear the counter, so the CCR0 interrupt will only trigger once per full cycle (2 seconds) and your delays will mostly be twice too long. Try instead:

> TACTL |= MC_1 | TACLR; // Up mode, clear counter

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MSP430F4784: one second delay using Timer