Disable Timers to avoid timing jitter?

Stefan_69 · August 22, 2020, 3:35pm

Hello,

is there a way to disable internal timers to avoid execution time jitter?
In my application it is crucial that the execution time of the code is reproducible and stable, timer interrupts might introduce jitter as they will (from time to time) execute additional code.

Thanks and best regards,
Stefan

Baozhu · August 24, 2020, 12:56am

Disabling it will render some functions unusable.The system tick-tock timer is also stable.

github.com

Seeed-Studio/ArduinoCore-samd/blob/master/cores/arduino/delay.c#L142


  }
}

/*
 * override this delay() when run RTOS
 */
void delay( unsigned long ms ) __attribute__ ((weak, alias("_real_delay")));

#include "Reset.h" // for tickReset()

void SysTick_DefaultHandler(void)
{
  // Increment tick count each ms
  _ulTickCount++;
  tickReset();
}

#ifdef __cplusplus
}
#endif

Stefan_69 · August 25, 2020, 7:21pm

Hello Baozhu,

thanks for the feedback, I’ll have to do some more in depth analysis of the jitter to get a better understanding if it causes a problem in my application. Basically I want to run my code without any external interference by timer interrupts.

I’ll post the results of my analysis in the forum.

All the best,
Stefan