CCS: TDA4VM:mcu timer period Imprecision

Hi Ronaldo,

I think I found the issue, can you please try to use the following piece of code in your application -

    /* The below goes to your main() where you are creating the timers */    

    config_pmu(); // for taking timestamp, you can use your own instrumentation
    TimerP_Params timerParams;
    TimerP_Handle timerHandle, timerHandle1, timerHandle2;
    TimerP_Params_init(&timerParams);
    timerParams.startMode = TimerP_StartMode_USER;
    timerParams.periodType = TimerP_PeriodType_MICROSECS;

    /* This should be more than the execution time of the ISR */
    timerParams.period  = 60000; //60ms
    timerParams.arg = NULL;

    /* This is the additional thing added */
    timerParams.intfreqLo = 19200000;
    timerParams.intfreqHi = 0;

    timerParams.runMode = TimerP_RunMode_CONTINUOUS;

    /* Use TimerP_ANY in all the TimerP_create() */
    timerHandle = TimerP_create(TimerP_ANY, (TimerP_Fxn)timer_handler, &timerParams);
    timerHandle1 = TimerP_create(TimerP_ANY, (TimerP_Fxn)timer_handler1, &timerParams);
    timerHandle2 = TimerP_create(TimerP_ANY, (TimerP_Fxn)timer_handler2, &timerParams);

    if (timerHandle != NULL_PTR)
    {
        TimerP_start(timerHandle);
    }
    else
    {
        AppUtils_Printf(MSG_NORMAL, 
        "Not able to create timer !!!\n");
    }
    if (timerHandle1 != NULL_PTR)
    {
        TimerP_start(timerHandle1);
    }
    else
    {
        AppUtils_Printf(MSG_NORMAL, 
        "Not able to create timer1 !!!\n");
    }
    if (timerHandle2 != NULL_PTR)
    {
        TimerP_start(timerHandle2);
    }
    else
    {
        AppUtils_Printf(MSG_NORMAL, 
        "Not able to create timer2 !!!\n");
    }

/* You can add you custom ISRs now, I would suggest the use of PMU to get the cycle count */

So the reason for the issue is that by default the timerParams have a field for the freq of the clock driving the timer and that by default is 25MHz and the actual clock however is 19.2MHz (I need to check if this is a bug and we need to change the default values)

So when you were configuring the timer for 1sec it was taking 1.3secs (as 25/19.2 = 1.3). So now when you override the default value by actual (19.2MHz) the behavior is consistent. I've used T = 60ms in the code. Also I use PMU counter to take time stamp, you can use your own method or use my reference code as below -

/* File needs to be included */
#include <ti/csl/arch/r5/csl_arm_r5_pmu.h>

#define PMU_EVENT_COUNTER_1 (CSL_ARM_R5_PMU_EVENT_TYPE_CYCLE_CNT)
#define PMU_EVENT_COUNTER_2 (CSL_ARM_R5_PMU_EVENT_TYPE_ICACHE_STALL)
#define PMU_EVENT_COUNTER_3 (CSL_ARM_R5_PMU_EVENT_TYPE_DCACHE_MISS)

/* To use PMU instrumentation, call the config_pmu() once during init time.
 *
 * Reset the counters using CSL_armR5PmuResetCntrs() API.
 * Then use CSL_armR5PmuReadCntr() with argument 0, 1 or 2 to capture value
 * of 1st, 2nd or 3rd PMU counter. 
 */

uint32_t config_pmu(void)
{

    CSL_armR5PmuCfg(0, 0 ,1);
    CSL_armR5PmuEnableAllCntrs(1);
    int32_t num_cnt = CSL_armR5PmuGetNumCntrs();

    CSL_armR5PmuCfgCntr(0, PMU_EVENT_COUNTER_1);
    CSL_armR5PmuCfgCntr(1, PMU_EVENT_COUNTER_2);
    CSL_armR5PmuCfgCntr(2, PMU_EVENT_COUNTER_3);

    CSL_armR5PmuEnableCntrOverflowIntr(0, 0);
    CSL_armR5PmuEnableCntrOverflowIntr(1, 0);
    CSL_armR5PmuEnableCntrOverflowIntr(2, 0);
    CSL_armR5PmuResetCntrs();
    CSL_armR5PmuEnableCntr(0, 1);
    CSL_armR5PmuEnableCntr(1, 1);
    CSL_armR5PmuEnableCntr(2, 1);
    return 0;
}

static uint32_t expt_ns = 1000000000UL;
static uint64_t timerTaskTS;
static uint64_t timerTaskTS1;
static uint64_t timerTaskTS2;

static void timer_handler(void)
{
    timerTaskTS = CSL_armR5PmuReadCntr(0);
    AppUtils_Printf(MSG_NORMAL,
                    " timerTaskTS: %u\r\n", timerTaskTS);
}

static void timer_handler1(void)
{
    timerTaskTS1 = LOCAL_getCycleCnt();
    AppUtils_Printf(MSG_NORMAL,
                    " timerTaskTS1: %u\r\n", timerTaskTS1);
}

static void timer_handler2(void)
{
    timerTaskTS2 = LOCAL_getCycleCnt();
    AppUtils_Printf(MSG_NORMAL,
                    " timerTaskTS2: %u\r\n", timerTaskTS2);
}

Output comes out like the following, showing 60ms between ISR hits for all 3 timers.

There is still one question however, how were you able to still get the correct timing initially with timerID = 0. But first we can try the above and get you unblocked.

Regards,

Karan