I have already ordered ATmega2561-16AU which has maximum speed of 16MHz with 4.5V - 5.5V power supply. But I want to operate it at 8MHz at 3.3V power supply. Since for 8MHz another part no. is there ATmega2561-8AU (1.8V to 5.5V) i am in doubt whether it is possible?
If use 3.3V as Vcc then will VOH be typically 3.3V? Is there any option to set VOH etc to different voltage than Vcc? eg. Vcc=5V and VOH=3.3V