ATmega644p reboots on serial input

raschemmel:
Nice job ! Can you give a brief summary of the advantages of this kind of board over the ones in production ?

Thanks. I like to work on breadboards, but wiring up the MCU, crystal, etc., again and again seems tedious. This approach eliminates that, takes less space on the breadboard, and results in a better circuit.

So similar in concept to boards like the Pro Mini or Adafruit's Boarduino, except unlike those I did not include a voltage regulator.