• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 79 subscribers
  • Views 399 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CCS/MSP432P401R: Delay function is incorrectly being optimised

Joonatan Renel
Prodigy 110 points

Part Number: MSP432P401R

Tool/software: Code Composer Studio

Hello!

I have the following issue when switching from the black MSP432 board to the new red MSP432 and a new compiler in Code Composer Studio 8.

A hard delay function gets optimised away and the program gets stuck in function. The delay function uses a timer interrupt to count the delays and
with the debugger I can see that the interrupt is firing and the delay variable gets decremented.

Can anybody help with this?

Here is the code:

/* These definitions are also used */
#define Public
#define Private static

/******** Here is the delay variable **********/

#pragma RETAIN(priv_delay_counter)
static volatile U16 priv_delay_counter = 0u;

/*********************/

/* delay function */
#pragma FUNCTION_OPTIONS(delay_msec, "--opt_level=off")
Public void delay_msec(U16 msec)
{
    priv_delay_counter = msec / 10;
    while(priv_delay_counter > 0u);
}


/* Interrupt service routine. */
//Hi priority interrupt handler.
Private void TA0_0_IRQHandler(void)
{
    Timer_A_clearCaptureCompareInterrupt(TIMER_A0_BASE, TIMER_A_CAPTURECOMPARE_REGISTER_0);
    if (priv_delay_counter > 0u)
    {
        priv_delay_counter--;
    }

    timer_10msec_callback();
}

  • 0
    Prodigy 110 points
    Ok, looks like I found the issue...

    On the black board I had been running the code I had also called out the function

    MAP_Interrupt_enableSleepOnIsrExit();

    in the init. Soo. maybe this feature did not actually work on the black board?
    In any case removing this call solved the issue.
  • 0 in reply to Joonatan Renel
    Guru 95585 points

    SleepOnIsrExit mode is a very specialized optimization, which your application has to be architected around (most aren't). If you're not certain that you Should use it, you Shouldn't.

    In practice I never use this feature, so it's possible it didn't work in the X silicon (black Launchpad). I defer to others on that.

    Personal opinion: I think it's unfortunate this function is peppered around the Examples suite. In each case I've seen, its use is not incorrect, but is unnecessary, and kinda teaches the wrong thing. But that's just me.

  • 0 in reply to Joonatan Renel
    TI__Prodigy 615 points
    Hi Joonatan Renel,

    Thank you very much for sharing your experience. As Bruce already wrote, SleepOnIsrExit shall only be used for purely interrupt driven applications, which in many cases may not be stated as clearly.
    I can't find another reason why it should not work on the black board right now. Maybe in the original project there has been another command which did clear the related SLEEPONEXIT bit before the ISR was triggered for the first time?

    Best regards,
    Max

**Attention** This is a public forum