Not finished, but my idea is to turn a ATMEGA 2560 into a kind of general controller,. You will be able to control each port on the 2560, each register (ADC, Timers , GPIO's port (A-L), each com port . In short : You use the serial port (0), where you type 2-5 chars commands to a local interpreter, which translates that command and initializers the actual register and / or IO-ports. My idea is to contol I2C (TWI), PWM, in short all by keyboard commands.