Code Compatibility

ATmega48P/88P/168P is code compatible with ATmega48PB/88PB/168PB.

To ensure that code designed for ATmega48P/88P/168P executes on the ATmega48PB/88PB/168PB the user must remember to change the device and recompile the code.

A general rule of thumb is that reserved bits should be written to zero if accessed. Reserved I/O memory addresses should never be written.