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Correct way to keep ms counter in FreeRTOS? Tick rate for 1Khz tasks?

Posted by apullin2 on August 21, 2014

Is there a right or "best practices" FreeRTOS way to keep an accurate millisecond timer? In the project that I am slowly porting, a 1ms counter was kept by a hardware timer peripheral interrupting at 1Khz, but that timer also existed to launch into a 1Khz task, and a 500Hz task (divided via a toggling bit).

Moving to FreeRTOS, to keep an accurate 1ms counter for the whole system, should I just keep that one hardware timer dedicated to counting milliseconds? Or should I always derive my sense of time in the system from tick periods? I mean, I'm sure both methods could be made to work, but I am trying to learn & achieve proper RTOS implementation here.

Hand in hand with this, is there a guideline for how fast I should set my tick rate if I have several 1Khz tasks? The MCU clock speed is 40Mhz.

Correct way to keep ms counter in FreeRTOS? Tick rate for 1Khz tasks?

Posted by edwards3 on August 21, 2014

I dont think there is a 'right' way. However it works for you. I would probably set the tick interrupt to 1KHz then just use xTaskGetTickCount().

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