Voltage input on digital pin (Arduino Uno)

retrolefty:
Those values are best defined and explained in the Atmel ATmega329p datasheet along with all the other electrical specifications for the chip.

Lefty

Unfortunately, that didn't help me :~

What voltage is that between? The uncertainty about "HIGH" and "LOW".
If you should say a voltage, were it would not anymore register a value as "HIGH" or the highest voltage you can think off, were it not at all would read it as "HIGH". (at least theoretically?)
Sorry... But I really need some sort of number, since I have made an error with an operational amplifier...
Hope there is some kind of possible answer :frowning: