X-Authentication-Warning: delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient: geda-user AT delorie DOT com
Date: Mon, 31 Aug 2015 06:41:57 +0200 (CEST)
X-X-Sender: igor2 AT igor2priv
To: geda-user AT delorie DOT com
X-Debug: to=geda-user AT delorie DOT com from="gedau AT igor2 DOT repo DOT hu"
From: gedau AT igor2 DOT repo DOT hu
Subject: Re: [geda-user] back annotation proposal (RFC)
In-Reply-To: <201508310341.t7V3fcfh022966@envy.delorie.com>
Message-ID: <alpine.DEB.2.00.1508310637471.6924@igor2priv>
References: <alpine DOT DEB DOT 2 DOT 00 DOT 1508301838470 DOT 6924 AT igor2priv> <201508301802 DOT t7UI2twS031311 AT envy DOT delorie DOT com> <CAM2RGhRgPQG2WDFVb0SFvMbypyYKS2oYtD=851WHR6fOB4iWdA AT mail DOT gmail DOT com> <201508310341 DOT t7V3fcfh022966 AT envy DOT delorie DOT com>
User-Agent: Alpine 2.00 (DEB 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
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 Sun, 30 Aug 2015, DJ Delorie wrote:

>
>> That makes a lot of sense for the netlist but what if you change a
>> footprint? I think there should be another tool that you run in
>> parallel to gnetlist to handle that.
>
> I assume a much more intelligent netlister.
>
> The netlister maps what it knows about each symbol to a list of
> candidate options for "heavifiing" the symbol into a full component.
> One of these options is the package, and once you somehow choose a
> package, there's one or more footprints that go with it.
>
> Part of my idea is that pcb takes all the choices it knows about and
> gives them to the netlister, so that the netlister can use that to
> narrow down the options it's left with after dealing with the
> constraints in the symbol.
>
> I.e. if you have a generic AND gate symbol, there's lot of options for
> the netlister.  But if this is a future iteration, pcb might already
> know that you picked a 74ALS00 in a SDIP-14 package with the SDIP14M
> footprint.  It can tell the netlister this when it does an
> update-import.  It can also tell the netlister what pin mappings were
> used.
>
> If the information in pcb is no longer valid for the device (i.e. you
> changed a 2-in AND to a 3-in AND), then the netlister would discard
> pcb's choices and start fresh.
>
> So, there's a lot of back-annotation information being sent from pcb
> to the netlister, which lets you do package, gate, and pin swapping in
> pcb, but none of it ends up back in gschem unless you do something
> specific to make that happen.
>

I generally like most of this. I have some constraints, tho: your idea 
needs massive gnetlist backend coding, which means a lot of scheme coding. 
I am not up to that and I have no contributor willing to do that. (Your 
idea also requires much more support in pcb-rnd, but I'm fine with that 
part.) Unless my contributor-problem gets solved, I will probably need to 
go for a simpler solution even if that is less generic.

Regards,

Igor2