X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient: geda-user AT delorie DOT com
X-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20120113;
        h=mime-version:in-reply-to:references:date:message-id:subject:from:to
         :content-type;
        bh=FIhCg39DJ3YKfKUz6MvHnuzcJzQXpF2QhqIq8dlcdVc=;
        b=IEQXu1f141gu1YbqeA50iIl1ViwdUJ5ESYWjg6nhR11vqZfMfLSstwJYii4zTIb6OY
         V3V8dr+Gs0iN5HZqM3iZbLERiv4VJ2g2VJGHpEkQ0hWSGD5QmZP8YFfIfdGRUCz/VQIK
         l+cfwTwC25BnuKfmIEbY7CIj6/X1WIoj3lU9NJFTmQFjPZCU6l/hQKrL4tIo+UVrgo8R
         DCa8JGI4i2PrWsFZXTtOJWWFozTK7uTneNVl8V2kugLee4ff4EUbEFzDJtfJbuCl4tc6
         8q5vBjEDe2nm7EALgLNakCEcaIXxYhmM/kDpTp58rd43w9sKIkF59X49Z+sKp0T3Czm5
         oyuQ==
MIME-Version: 1.0
X-Received: by 10.25.18.71 with SMTP id h68mr9282020lfi.94.1445737764962; Sat,
 24 Oct 2015 18:49:24 -0700 (PDT)
In-Reply-To: <20151024205644.39b5cad134a01926e79f86e5@gmail.com>
References: <CAM2RGhQhNkShqtN8uyCSd7R+V4FgLXDZTvTC2RTdmKF7C_8ndA AT mail DOT gmail DOT com>
	<201510220136 DOT t9M1a5Uw015222 AT envy DOT delorie DOT com>
	<CAM2RGhQOpnBXbZXngNq=RcQTZN=UrU+PGzTZ9AC=xKNfu_zQkQ AT mail DOT gmail DOT com>
	<201510220149 DOT t9M1nrIe016145 AT envy DOT delorie DOT com>
	<CAM2RGhQ26+gpcAeTdgJpBEh0egOGLYcpizQ+B6kfTQLowEk5xQ AT mail DOT gmail DOT com>
	<20151022023002 DOT GA25952 AT recycle DOT lbl DOT gov>
	<CAM2RGhQ7xfMDe1knmiFkW8MAZ4Sr=ZSas8Ca9Sadv3gJT2z3gw AT mail DOT gmail DOT com>
	<201510221643 DOT t9MGhFfg003310 AT envy DOT delorie DOT com>
	<20151022170259 DOT GA28154 AT recycle DOT lbl DOT gov>
	<CAC4O8c-AGwV59t6-K+73eaZt0d43bJe0kE8E68n9pWxaa9gP+Q AT mail DOT gmail DOT com>
	<20151024050756 DOT GA5741 AT recycle DOT lbl DOT gov>
	<CAC4O8c-5ukywtH+-=Zs=BXvLtn7WwdrabapkyrhEU7=ssvXqJA AT mail DOT gmail DOT com>
	<20151024205644 DOT 39b5cad134a01926e79f86e5 AT gmail DOT com>
Date: Sun, 25 Oct 2015 01:49:24 +0000
Message-ID: <CAM2RGhQGKaaQtvckLhzQ4RY5cj4e3DLX+Lt1NHDqSJysTK5mpg@mail.gmail.com>
Subject: Re: [geda-user] Star shorts
From: "Evan Foss (evanfoss AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
To: gEDA users mailing list <geda-user AT delorie DOT com>
Content-Type: text/plain; charset=UTF-8
Reply-To: geda-user AT delorie DOT com
Errors-To: nobody AT delorie DOT com
X-Mailing-List: geda-user AT delorie DOT com
X-Unsubscribes-To: listserv AT delorie DOT com
Precedence: bulk

On Sat, Oct 24, 2015 at 6:56 PM, Nicklas Karlsson
(nicklas DOT karlsson17 AT gmail DOT com) [via geda-user AT delorie DOT com]
<geda-user AT delorie DOT com> wrote:
>> > On to PCB (or any other layout too; John Doty can close his ears for
>> > this part).  AFAICT, there is no established technique to implement
>> > such a star short in a way that will pass DRC.  There needs to be
>> > copper half-inside the DRC process, that definitely shows up on the
>> > Gerber output.  This copper can't exist during the netlist check
>> > (optimize rats).
>>
>>
>> > To my feeble brain (it's been a difficult week) it would make sense
>> > to use a special-purpose layer for this job.  The star short component
>> > would put copper on it.  it would show up as part of one layer
>> > for every step except the rats processor.  I guess this extra layer
>> > could be paired with any copper layer?  And you could have star
>> > grounds (and this layer) for any copper layer?  The footprint would
>> > have to be carefully designed (and maybe depend on the design rules?)
>> > so that there's no chance of any copper, other than the wires attaching
>> > to the star, touching the ghost copper that makes the short.
>> >
>>
>> Another option would be to somehow have pcb keep it's nose out of any
>> connectivity that happens intra-footprint, since that's none of its
>> business, and make overlapping pads.  I was going to propose this, and then
>> realized that pcb would actually probably consider it a short.  So I think
>>  the current behavior (assuming it does complain) is not intuitive.  This
>> could lead to nasty results for broken footprints of course, but broken
>> (e.g. pin-swapped) footprints are always nasty and there's nothing gEDA can
>> do to catch that sort of thing.
>
> I think pcb design rule check should care about copper regardless of how it have been created because that's what physics like ohms law care about.

+1
The thing is there will always been structures that are creating some
function but are just too far ahead of what we have trained PCB to
understand.

>
> Nicklas Karlsson



-- 
Home
http://evanfoss.googlepages.com/
Work
http://forge.abcd.harvard.edu/gf/project/epl_engineering/wiki/