amaggio:
I had given some thought to proximity of xtal and serial wires but was space-contrained on my breadboard. Also because I am using a 3-pin resonator rather than a crystal, it's a bit awkward to place close to the xtal pins and I have run it out to a spare section of the breadboard.
I might rewire on a bigger breadboard and see if I can reproduce the reboot issue.Your board looks great Jack!
Thanks! If you're interested in making one (or just checking out the design), I posted all the necessary information on the Exhibition/Gallery board:
http://forum.arduino.cc/index.php?topic=234895.0