topic Re: timer callback latency issue in i.MX RT Crossover MCUs

timer callback latency issue

vasudhevan — Mon, 11 May 2020 16:21:22 GMT

Hi,

Board = imx rt 1064evk.

If i run evkmimxrt1064_gpt_timer example code timer generating 1 second delay.

Same code copied into my free rtos project but timer callback calling after 3-5 seconds delay.

GPT_GetDefaultConfig(&gptConfig);
    GPT_Init(ELMEASURE_GPT, &gptConfig);      /* Initialize GPT module */
    GPT_SetClockDivider(ELMEASURE_GPT, 3);    /* Divide GPT clock source frequency by 3 inside GPT module */
    gptFreq = ELMEASURE_GPT_CLK_FREQ;         /* Get GPT clock frequency */
    gptFreq /= 3;                             /* GPT frequency is divided by 3 inside module */
    GPT_SetOutputCompareValue(ELMEASURE_GPT, kGPT_OutputCompare_Channel1, gptFreq);  /* Set both GPT modules to 1 second duration */
    GPT_EnableInterrupts(ELMEASURE_GPT, kGPT_OutputCompare1InterruptEnable);    /* Enable GPT Output Compare1 interrupt */
    NVIC_SetPriority(GPT_IRQ_ID, 4U);/* Enable at the Interrupt */
    EnableIRQ(GPT_IRQ_ID);‍‍‍‍‍‍‍‍‍

Why timer callback interrupt latency more ?

How to solve this issue ?

Thanks & Regards,

Vasu

Re: timer callback latency issue

jeremyzhou — Tue, 12 May 2020 06:42:04 GMT

Hi Vasudhevan G,

Thank you for your interest in NXP Semiconductor products and
for the opportunity to serve you.
I think the delay issue is caused by GPT interrupt handler be preempted by other tasks or interrupt handlers which have higher priority.
So I think you should increase the interrupt priority to assure it will be serviced immediately.

Have a great day,
TIC

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Re: timer callback latency issue

vasudhevan — Tue, 23 Jun 2020 06:56:22 GMT

Hi jeremyzhou‌,

Sorry for the late reply.

Changed timer interrupt priority to 1.

Still having same issue.

NVIC_SetPriority(GPT_IRQ_ID, 1U);/* Enable at the Interrupt */‍

Regards,

Vasu

Re: timer callback latency issue

vasudhevan — Mon, 06 Jul 2020 10:48:56 GMT

Hi jeremyzhou‌,

GPT timer not working properly.

Now i have used QTMR for generating 1sec callback function.

QTMR timer working fine.

Thanks & Regards,

Vasu