A few days ago I read the information available about the ArduPilot Mega board and also reviewed the schematics. I searched for the information on this site as well as the SourceForge repository. Since I design embedded systems for a living, I thought that I could understand the design very quickly. Understanding the software from the source code was quite easy; however, the schematics proved to be quite a riddle. There are so many pins on the pair of on-board processors that end in never-never land, that I must ask, this forum to please explain what they are for. In addition, I wonder if there is provision for communication between the Mega1280 and the Mega328 and if there is how it is accomplished?