gEDA-user: slotting and power pins

[Duncan Drennan <duncan.drennan@xxxxxxxxx>]

Currently the symbol slotting functionality struggles to handle power
pins well (at least that is what some brief googling showed). A
recurring theme with regards to slotting is that power pins show up on
all the slots, e.g. dual/quad opamp which has a single set of power
pins for each of the opamps - if the power pins are visible and not
embedded they show up on each slot.

Some people have a problem with this from a "style" perspective (it is
visually different to other CAD packages). A slightly more important
issue is that if the pins are left unconnected (for more readable
schematics) it messes with the DRC checking, which expects all pins to
be connected (and possibly with the netlister?).

I had a thought which might solve both of these issues. If a special
character was defined for slotting which indicated that the pin should
be excluded from the schematic that character could be used in place
of the power pin slot.

So for a dual opamp with slots defined

slotdef = 1:3,2,8,4,1
slotdef = 2:5,6,8,4,7

it would become

slotdef = 1:3,2,8,4,1
slotdef = 2:5,6,N,N,7

if 'N' was the special character. The 'N' pins would then be ignored
by the rendered, DRC, netlister, etc. Maybe even just slotdef =
2:5,6,,,7 would work too. Maybe this has already been done?

I have absolutely no idea how the internals work for rendering the
symbol and passing the info to the DRC and netlister. Just thought I'd
share the idea in case anyone is interested.

Regards,
Duncan

-- 
Turn ideas into products - http://www.engineersimplicity.com
The Art of Engineering - http://blog.engineersimplicity.com


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