Most interested in finding how the I/O pins are interfaced to the internal bus, and whether or not they have internal pull-up’s. If anyone has a simple schematic or can point to it, it would be much appreciated. They seem to drive a lot of current (40 mA.) so I would imagine there is a transistor, or something like CMOS except faster.
I was thinking of what is the best thing to do with unused pins, although it seems to work if the pins are left unconnected, is it better to ground or pull them high?