Repeatability of output pulse timing using hardware timers

[chrisknightley]

@compgeek275

Interestingly, I dug out my Uno and ran a simple PWM test there, and observe <1usec jitter 100 ms after a reference pulse. That board has a crystal (and obviously a different chip) - is that the difference? Maybe I’ll just have to switch platforms for this.

ATmega4809 the MCU installed in Nano Every has equipped with a high-precision RC oscillator.
However, although it is highly accurate it is naturally inferior to the crystal oscillator.
And unfortunately Atmel has removed the external oscillator from the AVR of this series.
If you want more accuracy by Xtal, you need Xtal and an external oscillator.
And changing to a board with external oscillator included MCU, is not a bad option.