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LP-AM243: The clock systick on AM243x-LP

matt.wen
Prodigy 110 points
Part Number: LP-AM243


Hello

I need to use the Clock Tick in AM243x to generate a 1ms tick, now I have configure it in "example.syscfg". I also write a clock callback and clockParams to put in clockObj as following code

uint32_t gOneShotCount = 0;
uint32_t gPeriodicCount = 0;
void myClockCallback(ClockP_Object *obj, void *arg)
{
    uint32_t *value = (uint32_t*)arg;
    (*value)++; /* increment number of time's this callback is called */
}
ClockP_Params clockParams;
ClockP_Object clockObj;
ClockP_Params_init(&clockParams);
clockParams.timeout = ClockP_usecToTicks(100*1000);
clockParams.period = clockParams.timeout;
clockParams.start = 1;
clockParams.callback = myClockCallback;
clockParams.args = &gPeriodicCount; /* pass address of counter which is incremented in the callback */
ClockP_construct(&clockObj, &clockParams);
When I debug the project, I found it can enter into the interrupt ClockP_timerTickIsr(void *args)   and do myClockCallback only once, next time enter into ClockP_timerTickIsr(void *args) I check the code with single step and find obj->timeout is changed to 1879626760, it cause that it will not enter into myClockCallback, so I don't know the reason.
Could someone can help me? thank you
  • +1
    TI__Guru 55695 points

    Hi Matt,

    For your use case, it is better to use TimerP instead of the ClockP. The ClockP is providing the system clock (heartbeat using Timer8). There are 7 more timers can be used by users. Here is the code section for TimerP setup (empty.c):

    int myTimerCallbackCount = 0;
    void myTimerCallback(void)
    {
        myTimerCallbackCount++;
    }

    void empty_main(void *args)
    {
        TimerP_Params timerParams;

        /* Open drivers to open the UART driver for console */
        Drivers_open();
        Board_driversOpen();

        DebugP_log("All tests have passed!!\r\n");

        TimerP_Params_init(&timerParams);
        timerParams.inputPreScaler = CONFIG_TIMER0_INPUT_PRE_SCALER;
        timerParams.inputClkHz = CONFIG_TIMER0_INPUT_CLK_HZ;
        timerParams.periodInUsec = CONFIG_TIMER0_USEC_PER_TICK;
        timerParams.oneshotMode = 0;
        timerParams.enableOverflowInt = 1;
        TimerP_setup(gTimerBaseAddr[CONFIG_TIMER0], &timerParams);
        TimerP_start(gTimerBaseAddr[CONFIG_TIMER0]);

        while (1)
        {
        }

        Board_driversClose();
        Drivers_close();
    }

    Here is the example.syscfg screen capture:

    I have tested it on AM243x LP. It works fine.

    Best regards,

    Ming

  • 0 in reply to Ming Wei
    Prodigy 110 points

    hello, ming

    Thanks for your help, I will test it