Using ATtiny84 pins as input

Question

I'm fairly new to working with electronics so I apologize for my lack of understanding of a few things. I'm working with an ATtiny84 and I was wondering what the max. voltage and current are when I use a pin as an input pin.

I looked through the datasheet hoping for some answers but I ultimately came out confused. I also searched online for some answers but many were conflicting or hard to understand.

Here's some of the content from the page I looked at on the datasheet:

When they say "voltage on any pin" are they referring to the applied voltage (i.e. voltage going to the pin)? Or the voltage that can come out per pin?

Answer 1

The absolute maximum ratings refer to the voltage "going into" the pin (applied to it from outside the chip). The "output high voltage" and "output low voltage" specifications refer to the voltage that's put out by the chip itself, if the pin is configured as an output.

In short, if you use a pin as an input, the input voltage must be between 0V and the chip's supply voltage. So, if you operate the chip at 5V, you can apply anything between 0V and 5V to the inputs. (Technically, you can go outside of that range by an additional 0.5V, but you really shouldn't.)

The separate specification for the Reset pin is for programming only. (Your programming adapter can apply 12V to it to put the chip into programming mode.)

When configured as an input, a pin will not draw any current, so the current rating does not apply to inputs.