I am trying to attach an external oscillator to an interrupt pin.
The oscillator is to act as a reference clock/timing standard, because practice has shown that the internal clock(s) are not accurate enough, due to the use of resonators in the processor clock circuit.
I have tried various AVR Arduinos but the latency in handling the ISRs is a problem.
I have even tried a ESP32, which was even worse.
I was looking around the internet and found a YouTube video were the person was using an Arduino Zero in a similar way to generate a more reliable clock, but at a lower frequency than I can get away with.
I have an Arduino Zero in another project that is in use most of the time, however I am now considering giving it a try. Before dismantling this project I wondered if anyone has an actual figure for the number of program cycles and/or the max input frequency the Zero ISR will handle reliably.