* This project replaces the firmware preloaded onto the XPLAIN's onboard AT90USB1287 microcontroller.
*
* When power to the board is applied, the TDI pin (pin 9) of the USB AVR's JTAG port is read. If the pin is left high, the device
* will enumerate as a regular COM port on the host, which can then be opened and data exchanged between the XMEGA and Host as if
* the XMEGA was connected directly to the host's serial port. If the pin is pulled low by shorting it to GND (pin 10), the device
* will enumerate as an AVRISP-MKII to the host, so that the XMEGA can be reprogrammed by AVRStudio or other compatible software
* This project replaces the firmware preloaded onto the XPLAIN's onboard AT90USB1287 microcontroller.
*
* When power to the board is applied, the TDI pin (pin 9) of the USB AVR's JTAG port is read. If the pin is left high, the device
* will enumerate as a regular COM port on the host, which can then be opened and data exchanged between the XMEGA and Host as if
* the XMEGA was connected directly to the host's serial port. If the pin is pulled low by shorting it to GND (pin 10), the device
* will enumerate as an AVRISP-MKII to the host, so that the XMEGA can be reprogrammed by AVRStudio or other compatible software