Jay
Sounds
like you need to hire a consultant to help you out. There is one linked on
the CadSoftusa.com web site for eaglecad. That might make sense for you.
Also some collage classes offer project building.
Al
Welch
-----Original Message-----
From: jay marante [mailto:jaythesis@yahoo.com]
Sent: Thursday, July 08, 2004 8:50 AM
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] Autoroute (was Re: OT: Eagle 4.11 ...)can someone please guide me with PCB designs? im trying to make my first PCB with eagle. also, i can't find a mega16 in the AVR library. and, i don't know anything about the "rules" in designing a good circuit board. thanks...-jay
Graham Davies wrote:--- In AVR-Chat@yahoogroups.com, "Phil" wrote:
> I find the eagle autorouter to be pretty dumb.
I would like to disagree with this, but agree with the general
direction of the discussion. I use Eagle and think that the
autorouter is pretty good and darned good for the money. This is my
methodology:
Small, double-sided boards with mixed through hole and surface mount.
Draw schematic. Place components guided by airwires. SAVE. Autoroute
with goal of 100%. Quit, don't save, re-open unrouted board. Try
again, changing settings such as preferred direction on each layer.
Repeat until autoroute is 100% or near, moving components if
necessary. Note best directions. Starting with unrouted board, lay in
ground, power and critical nets by hand, keeping to best directions
on each layer. Autoroute from time to time, but always discard. Look
for congestion and adjust placement and hand-laid traces to relieve.
When satisfied, autoroute and save. Look for and fix stupid routes.
Route any unrouted traces by hand. Look for other improvements as
time permits. Fatten up ground as much as possible, perhaps using
polygon floods. For best EMI performance, when the ground is laid in
by hand you need to form a grid, not just a meandering wire, with
apertures in the grid as small as possible. This provides multiple
return paths for signals and greatly reduces emission of and
succeptibility to EM interference. Of course, if things are really
bad you need a full ground plane but at minimum you need a grid.
Graham.Do you Yahoo!?
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