Also helps to read this Atmel Application note, section 5, where it describes what the internals of the OSC1 & OSC2 pins are and how they are to be connected to external components such as crystals.
Also helps to read this Atmel Application note, section 5, where it describes what the internals of the OSC1 & OSC2 pins are and how they are to be connected to external components such as crystals.