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Subject: Re: [Homebrew_PCBs] Using Eagle

From: Stefan Trethan <stefan_trethan@...>
Date: 2009-10-10

Yes that's the way to go, placement is everything.

Personally, I find that roughly one third of the time is taken up with
placement, one third with routing of 95% of the traces, and one third
with the remaining 5% of traces.

Placement could be speeded up greatly if the layout software initially
used the same arrangement as schematic (because generally components
that are close together on the schematic end up close together on the
PCB). The Altium designer web demo says it can do this, but so far the
feature eludes me in the trial version I have installed (like most
other functions of altium designer). Anyway, with more effort you can
do this manually in any software, shifting components around and
together into functional groups, and then shifting the individual
groups around until they make sense. Once that is done I start pulling
everything back into the board outline one functional group after the
other. Only then I start routing.

It is really a big advantage to have two monitors and the schematic on
the second for this work, especially if the software supports cross
probe highlighting the component you shift around.

It is also a very big help for me to have colored ratsnest lines,
otherwise the common power and ground make it hard to see which
components belong together.

There are two kinds of people, the ones that think every PCB is a
piece of art, and will never be satisfied with the work of an
autorouter. And the other kind who don't care about the look of the
board as long as it works electrically. There is no right and wrong,
but personally don't respect any work done without care and attention
to detail.



ST

On Sat, Oct 10, 2009 at 2:13 PM, Barry Demers <sdad@...> wrote:
> For my single side boards I started  with the rat's
> nest and kept moving things around I had as few lines as possible crossing
> each other.  Using that positioning as a guide I then started introducing
> traces until I was satisfied.  Really is fun!  A lot like a labyrinth
> puzzle.