SouthernBinary:
The question is for CHANGE. It says whenever the pin changes values but this is vague. For my 1284p the interrupt is on the TX1 pin which is digital. This should mean it interrupts whenever there is a rising or falling edge.
I don't see a TX1 pin on the datasheet. Do you mean TXD0 (pin 15 on the chip)? Or TXD1 (pin 17 on the chip) which is also INT1?
That is not listed as an an ADC input and thus the interrupt would trigger when the voltage level rises above or below the level required for a digital transition.
I'm just nit picking on the website's explanation
Which website? Which explanation?
It says whenever the pin changes values but this is vague.
I don't recall any of the external interrupts (to which the attachInterrupt documentation refers) being analog inputs. Therefore the explanation is not vague. Its value is either HIGH or LOW.