free rtos gpt timer callback latency issue

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free rtos gpt timer callback latency issue

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vasudhevan
Contributor V

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

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danielchen
NXP TechSupport
NXP TechSupport

Hi Vasu:

 

For your gpt timer issue, I would suggest you check your gpt timer input clock source and  prescaler from regiter GPT_CR and GPT_PN.

In the official demo, the input clock source is ipg_clk.   The variable getFreq in the official demo is 75000000 .

If your project use the External clock as the input clock source, then the timer interrupt should be longer than 1 second.

 

Regards

Daniel

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danielchen
NXP TechSupport
NXP TechSupport

Hi Vasu:

Do you use the latest version SDK 2.7?

Regards

Daniel

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vasudhevan
Contributor V

Any update ?

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danielchen
NXP TechSupport
NXP TechSupport

Hi  Vasu:

Sorry.

I copied the code into hello world example, and it works as expected.

pastedImage_2.png

Could you please attach your project here?

Regards

Daniel

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vasudhevan
Contributor V

Hi Daniel,

      Sorry for the late reply.

      If run example code working fine.

      Same code copied into our free rtos based project timer callback function triggers every 2-5 seconds latency.

      Why timer callback function latency is more ?

Thanks & Regards,

         Vasu

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danielchen
NXP TechSupport
NXP TechSupport

Sorry I forgot to tell you,    my test result is ok to run the gpt timer in a freertos task.

For your case, I would suggest you toggle a LED in the gpt timer ISR to check the real result.

Or you can send me a simple project to me to reproduce your issue on my side.

Regards

Daniel

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vasudhevan
Contributor V

Hi Daniel,

       Sorry for the late reply.

       timer callback latency issue This is my one thread.

       When i was using QTMR timer working fine for me.

       Still i am not able to find out why gpt timer is not working.

       I have checked all possible interrupt priority but still no success.

Thanks & Regards, 

      Vasu 

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vasudhevan
Contributor V

Hi Daniel,

    I am using latest SDK 2.7.

Regards,

   Vasu

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