gEDA-dev: collecting/sharing scripts

[Igor2]

On Mon, 4 Sep 2006, Dan McMahill wrote:

<snip>

>I think that this is an issue which really should be addressed.  In at 
>least some CAD systems (Accel/PCAD is what I have in mind here), a 
>component consists of a symbol, a footprint, and a small spreadsheet 
>type database that says:
>
>symbol pin #1 is "IN+" and is footprint pin "3"
>symbol pin #2 is "IN-" and is footprint pin "2"
>etc.
>
>Thats also where slotting information goes.
>
>I wonder if maybe the way to go is to start with a basic symbol where 
>you've put things like
>
>@footprint@
>@pin1@
>@pin2@
>
>and a few other entries in the symbol as place holders and then have a 
>script that runs perhaps at library build time and whenever the usr 
>wants to run it that builds up heavy symbols from the generic symbols.
>
>For those who don't like "heavy" symbols, I'll note that to some extent 
>we don't really have "light" symbols but rather "medium" and "heavy" 
>symbols.  Because as Igor is seeing, the true pinout is part of the symbol.
>
>-Dan
>

The system I would really like is a bit different. Note: I'm really a
hardcore console-junkie, means I use text console (80x25) and start X only
when I really have to, so I know the system I would like probably doesn't
match with the ones majority of the gEDA users would like.

So, I would change symbols in a way so that they don't say pin 1, pin 2
and such, rather pin names while I would keep footprints as they are now,
with pin numbers. I would then set up a database (probably a collection of
text files) which would map specific symbol pin-names to specific
footprint pin-numbers, let's call it meta-symbol database. When using
gschem, I would exclusively use this meta-symbol database to choose
components. At gui level the selection differs: after I choosed a
component, say 7805, I would be able to choose the packaging (so the
program would offer me the list of the meta-symbols which has 7805 in the
symbol file); I could choose TO220 or SO8 or something. On property level
it means no footprint property, but a meta-symbol-id property and gsch2pcb
would need to look up the database while generating the netlist.

I think adding a new meta-symbol would be easy too, both by editing text
files or by having a GUI dialog: I need to look up the datasheet and
connect symbol pin names to footprint pin numbers. Once I did it, it is
stored in the database and I will never need to care again. 

Of course if there are different pinouts for the same symbol/footprint
combination, like different manufacturers swap pins, we would need to have
more than one record in the meta-symbol database. Maybe to identify an
actual component, we would need the symbol, the footprint and the
manufacturer. 

Well, just an idea, maybe useless (I haven't really followed the
discussion about heavy vs. light and don't have much experience in
creating gschem symbols either).

Regards,

Igor2