Beschreibung:        <http://www.mikrocontroller.net/articles/AVR_Bootloader_FastBoot_von_Peter_Dannegger>

Bootloader V2.1:     <http://www.mikrocontroller.net/topic/73196#850843>

Linux Host Software: <http://www.mikrocontroller.net/topic/73196#1955077>

RXD = PORTD0
TXD = PORTD1