I am starting to develop a shield for the arduino, but I'm new to eagle CAD. I stripped down the arduino schematic I got from the arduino 2009 spec. page, and had a few questions before I continue...
First of all, I know that there is only one 6 pin header on the bottom... that's on purpose.
I am wondering though, what the red and blue dashed outline rectangles are? Are they necessary? Finally, there are 3 red circles, and eagle calls them fiducial points... are they necessary?
I don't like that one cause I need the mount holes in the exact positions as the 2009, and my pinout is cut down, even more than in the pic I linked (only like 12 pins remain)