I'm drawing my first schematic, and I would appreciate some comments on my current result.
In particular, I have the following doubts:
R1 is 47K in AT90USB design, 10K in the datasheet
C4, C5 are 15pF in AT90USB design, 22pF in the datasheet
VCC to +5V or to +3V3? (according to the AT90USB647 datasheet +3V3 is OK).
UCAP is connected to +5V in the reference design. (only connected to a cap according to the AT90USB647 datasheet?)
the png and pdf files can be viewed also on http://www.tty1.net/usbi2c/.