Re: gEDA-user: Bug report for renaming slots [Was: Re: gEDA on windows]

[Joerg <joergsch@xxxxxxxxxxxxxxxxxxxxx>]

Peter Clifton wrote:
> On Mon, 2009-01-12 at 18:53 -0800, Joerg wrote:
>> Peter Clifton wrote:
> 
>>> Actually, your idea has got me thinking more about how we handle
>>> attributes on slotted parts, and the possibility that they could in some
>>> way be treated as an aggregate component for the purposes of attributes
>>> other than "slot=".
>>>
>> Not 100% sure if I understand correctly but yes, treating all slots as 
>> one component would be feasible. Even if you don't use all you must 
>> usually place all slots anyhow and, for example, connect inputs to GND. 
>> Exception being transistor arrays but even they should also be grounded 
>> and be on the schematic so folks can see what's available for cut/jumper 
>> style rework purposes.
> 
> Sorry for typing before thinking that through fully. Treating all slots
> as one component (for adding attributes) isn't actually possible with
> gEDA's architecture. Attributes can only be added to symbols.
> 
> I can imagine the GUI glossing over that fact, and perhaps offering to
> help keep attributes in sync when renaming a single slot, it would be
> difficult (perhaps impossible) to cater for the case where you have some
> slots on one schematic page, and others elsewhere.
> 

Most of the time engineers could live with the restriction that all 
slots must be on the same page. Not perfect, but should be quite acceptable.


>> That would be a serious one. I can't recall a single company I dealt 
>> with not using A, B, and so on (upper case). Most CAD programs 
>> auto-assign those when you place until you run out of slots. So if you 
>> place eight slots of a six-slot 74HC14 it bumps the refdes number for 
>> the last two you place. They don't all do it perfectly. OrCad usually 
>> does but I've had Eagle "forget" when I began placing some more slots 
>> later. gschem just places all as first slots with U? right now.
> 
> Tricky to figure out how to do this flexibly. gEDA's flexibility means
> special casing behaviours like this is hard (and often undesired). Some
> kind of script or plugin hook might be a possible way to do this, but
> again.. I'm just thinking "aloud".
> 
> (I'm not suggesting users would have to write these scripts, more that
> they shouldn't form part of gschem's hard-coded behaviour.)
> 
> As an example I wrote for someone (and I ended up using it myself), I
> have a script hook here which renames any component I copy back to
> "U?" (removes the numbering), so that I don't end up accidentally naming
> two components the same due to a copy-paste in my schematics.
> 

Most CAD systems use such routines and they can be called from within 
the application. Eagle calls them user language programs (ULP).

> 
> Joerg: I think I have some understanding now of the kind of visual
> appearance of schematics you're thinking of, but I'm curious to see (if
> you have any examples you could share - perhaps by private email), just
> what the kind of schematic you're talking about looks like. (Either
> slotted logic gates, or slotted op-amps).
> 
> I'd like to put the discussion in context by seeing how a real schematic
> looks using the styles we discussed, rather than just my mental pictures
> so far, which just cover a symbol and its visible pins.
> 

A bit problematic because most of my stuff is client designs. But I'll 
find something suitable. On the web I found your pcjc2 email address at 
Cambridge, let me know in case that isn't correct anymore. I am reading 
this group through gmane which hides people's web identities.

-- 
Regards, Joerg

http://www.analogconsultants.com/



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