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FreeRTOS SW Timers inaccurate

Posted by smurali on January 9, 2018

We have been using FreeRTOS SW timers all this while for periods ranging from 10ms to 1 minute. Recently we added a timer for 5 minutes. This paritcular timer seems very inaccurate. It usually takes around 5 minutes 45 seconds to trigger the interrupt. Is there something that i am missing?

configTIMERTASKPRIORITY is 2


FreeRTOS SW Timers inaccurate

Posted by rtel on January 9, 2018

Is there something that i am missing?

Don't know, as I don't know what you have.

Which port are you using? Does the chip have a stable and accurate clock? Or is it using a lower accuracy internal resonator? Have you checked the accuracy of the clock and the tick frequency using a scope? Are you setting the tick frequency to something that can be achieved exactly, or are you using a slow low power clock and attempting a tick frequency that can't actually be achieved exactly (considering rounding errors, etc.).


FreeRTOS SW Timers inaccurate

Posted by smurali on January 10, 2018

We are using a port with 64MHz CPU clock which is stable. The configTICKRATEHZ is set 1000


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