On Sun, 28 Sep 2008 07:06:57 -0400, Ales Hvezda wrote:

>>IMHO, if such a program is supposed to do its job without manual
>>interaction, it is no better than a heavy symbol lib. They both need to
>>be maintained locally to fit the local requirements.
> 
> 
>       Let me make sure I understand your above statement.  You do
> _not_ want whatever program/mechanism to automatically do things.

Yes and no. I want the program to automatically make default choices. 
These default choices should be configured according to my local needs. 
But I have to be able to override these choices on a per instance level. 
There usually is a small subset of sensible values, that cover almost all 
cases. 

So there are three cases with very different abundance:

1) 95%  --> the default applies

2) 4.9% --> the desired value is one of a small set 

3) 0.1% --> some exotic value that may be specific to this project only

Consider a resistor. The vast majority of resistors in my designs are 
0805. But some are wired, or in a TO247 housing. With a HV project there 
might be a special resistor. On schematic level these exceptions are 
represented by the same graphics as the default. It is logical to use the 
same gschem symbol for every resistor. Currently, I can do a heavy symbol 
with 0805 footprint attribute, which is promoted and visible in the 
schematics. This covers case 1). 

In the gschem GUI, I can manually type in the footprint attribute to any 
value. This is appropriate for the rare case 3). However, it is a bit 
awkward for the more common case 2). Given the sometimes not so catchy 
names of footprints, I constantly need to look-up names in the footprint 
libs. IMHO, the altium programmers found a good way to deal with this 
situation: In protel95SE  is possible to select from a short list of 
footprints in the schematic editor. Yes, this means an extra heavy 
symbol. But the benefit is, I only need to make sure once that footprint 
is a correct choice for a given symbol.


> You
> want to choose the footprint yourself (which would then apply the
> correct pin mapping etc...).

I tend to regard the pin mapping as a fixed property of a symbol. With my 
projects only few components come with different pinouts. From the top of 
my head only offset compensation of opamps and laser diodes seem to fit. 
In these cases I am content with an extra symbol for the other pinout. No 
need to add file format complexity for these rare cases.

---<(kaimartin)>---
-- 
Kai-Martin Knaak
http://lilalaser.de/blog



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