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Message-ID:	<525AC3B0.5080703@penguindevelopment.org>
Date:	Sun, 13 Oct 2013 18:00:48 +0200
From:	Peter <link AT penguindevelopment DOT org>
Organization:	Penguin Development
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To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] Dealing with internal connections
References:	<525AADB0 DOT 8030508 AT penguindevelopment DOT org> <525AB9A5 DOT 2060109 AT estechnical DOT co DOT uk>
In-Reply-To:	<525AB9A5.2060109@estechnical.co.uk>
Reply-To:	geda-user AT delorie DOT com

On 13/10/13 17:17, Ed Simmons wrote:
> On 13/10/13 15:26, Peter wrote:

> Perhaps you could instead use a symbol with four pins like you have
> 'drawn' above... then you could also use the footprints with pads
> numbered 1-4. You could show the connection in the symbol easily, with
> the design intent clearly set out in the schematic.
>
> When it comes to PCB, it would still complain about the pads not being
> joined, but ignoring the rats between switch pads doesn't seem too awful.
>
> When I complete a PCB layout, it's quite common for me to short ground
> planes to connector shells... these don't always have the corresponding
> pin in the schematic. Usually by the second revision of the design I've
> tidied these up and added the appropriately numbered pins to symbols to
> show these connections and prevent PCB from complaining. ;-)
>
> Hope that helps...
>
> Ed
>
Using a 4-pin symbol is what I'd like to avoid having to do, because 
when routing the PCB, I'll sometimes decide it's useful, for example, to 
connect only pins 1a and 2b -- but then, after some reconsideration, 
I'll suddenly see a more efficient way that instead requires pins 1b and 
2a to be connected, or requires "hijacking" the internal connection 
between pins 1a and 1b as a bridge across tracks routed underneath the 
switch. All of those things would require changing the schematic during 
editing.

Your idea of going with the "wrong" version first and cleaning it up in 
a later revision does sound good, though; I could just use two 
nearly-identical footprints, one with multiple identically-named pins 
for development, and one with different pins for "release"; then I'd 
just have to change the schematic to match the PCB once, and using 
"import schematics" would hopefully magically "fix" the routing.

Cheers.

Peter
-- 
http://www.penguindevelopment.org/ -- Free and open source software and 
hardware

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