the ATmega328P datasheet which tells me Operating voltage is 2.7V to 5.5V
Where are you looking?
The cover page of the ATmega328P data sheet, titled "Features", looks like this:
the ATmega328P datasheet which tells me Operating voltage is 2.7V to 5.5V
Where are you looking?
The cover page of the ATmega328P data sheet, titled "Features", looks like this: