According to the ATmega48PA datasheet "All I/O pins have protection diodes to both VCC and Ground...".
In my case, I would like to use the PD6 (PCINT22/OC0A/AIN0), as the analog comparator positive input. The incoming voltage may be a negative value (ex. -2V). So, I would like to ask you if in the case of use of an alternative input function (like Ana.Comp, ADC), the internal clamping diodes are still connected or not. ???