On 24/12/2010 00:53, Nathan House wrote:
> I think I've corrected the mistakes that were noted. Here's the new
> schematic and layout:
>
> Schematic: http://www.roboticsguy.com/images/misc/pic18f4550_tqfp_schemat=
ic2.png
> Layout #1: http://www.roboticsguy.com/images/misc/pcb1.png
> Layout #2: http://www.roboticsguy.com/images/misc/pcb2.png
>
> Do the new schematic and layout look any better? Any more suggestions
> how I can improve them?
>
> I think the biggest problem that people noticed with the board was the
> ground loop. I posted two different ways of routing the ground traces
> above; is one better than the other?
>
> Thanks again for all of your help, everyone!

Both look reasonable to me, not much to choose between them - probably=20
as good as you will get for a single layer layout without lots of jumpers.
If pushed I might pick the second one as it has a better approximation=20
of a star ground (the first looks to have a larger loop area)
This is at a glance though, others may disagree. Both should work okay=20
though (assuming no plans to use the analogue peripherals for sensitive=20
tasks)
I have had a 4550 running 20MHz crystal and USB fine on a breadboard=20
with a fairly dodgy layout.
I would go ahead and try it out now - good luck..



--=20
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