Backup for last state of task on Arduino

[dougp]

A primitive but functioning approach.

ATMEGA328P analog input comparator - using

The " 40001906A.pdf" document that you linked to is for the ATmega328PB, and you say that you have the ATmega328P. Those are not the same. :question:Do you want to measure the VCC to check if it is going down ? But instead of polling (with the known and often used solution) you want a trigger to a interrupt ? And you also want to keep using PD6 as a digital pin. Writing to EEPROM from an interrupt routine is possible. If you can put that trigger in code, then it is a good solution. I'm sorry …

I'm trying to flesh out this idea but have nothing worth posting right now.