Re: gEDA-user: Power (and other non-graphical) pins

[Stefan Salewski <mail@xxxxxxxxxxxx>]

Am Montag, den 12.01.2009, 14:54 -0700 schrieb John Doty:
> 
> Sounds miserably complex and inflexible. While with gEDA, you break  
> the physical device up however you choose, into as many symbols as  
> you want, and there's nothing magical about power pins.
> 

Indeed, I think handling of power pins and slotted devices works fine in
gEDA and is not too complicated.

But we should not close out eyes ignoring other solutions.

I think there is at least one problem: Some devices have multiple power
pins, i.e. 4 for VCC and 4 for for VEE. Or some devices have multiple
output pins for very low output resistance. There is no really nice
solution to handle these internally connected pins. I asked about this
problem on this list long time ago, I think recommendation was to make
all pins visible. So for an 16 pin differential OpAmp we have 4 pins for
VCC. I am not too happy with this,see

http://archives.seul.org/geda/user/Oct-2007/msg00126.html

Another minor problem: If we have a slotted OpAmp with separate power
pin symbol, then we have to ensure that all these symbols have the same
refdes. I have to admit that some time ago I forget to give the power
symbol the same refdes.

Related to this: If we add new symbols to schematics, we may not want an
automatic renumber operation because pcb layout is already done. So we
number the new device ourself and have to ensure that the number does
not exist. OK, I think recent gschem can renumber new devices while
leaving old refdes unchanged. But if an unwanted duplicate refdes is
there, there is no warning I think.

Minor problems, and I have to admit that I have spend no time thinking
about an improvement yet.

Best wishes,

Stefan Salewski
    



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