Still trying to gather info. for the schematic. If I understand correctly I should have decoupling/bypass capacitors for each pair of the following:
100nF(0.1uF) PINS
UVCC - UGND (2, 5)
VCC - GND (14, 15)
AVCC - GND (24, 23)
VCC - GND (34, 35)
AVCC - GND (44, 43)
VBUS - GND (7) -> ground plane (10uF)
I've come across the suggestion to place the caps on the bottom of the PCB directly beneath the pads for the IC with vias to make the connection. Am I on the right track?