Mail Archives: geda-user/2015/12/08/22:29:33
On Tue, 8 Dec 2015, DJ Delorie wrote:
>
>>> So already the refdes isn't a unique identifier for a symbol...
>>
>> In such case it is a slot and the slot number could also be used?
>
> Sometimes. Other times, like large MCUs, there are no slots, just
> different symbols using the same refdes, which the netlisters just
> merge together.
>
> At best, "refdes + pinnumber" may be a unique identifier, *except*
> that changing the refdes and/or pin numbers changes the identifier...
> and those are the things we want to change.
Refdes+pin sounds like a good identifier on PCB-side, but not on
gschem-side.
When I use stock dual-opamp-1.sym (slotted) pin+refdes it's not unique in
the sense that there are two instances of the very same power pins (4 and
8) on the schematics.
If I connect Vcc to pin 4 on slot 1 and gnd to pin 4 on slot 2, I get the
following netlist (in the gsch2pcb flow):
Vcc U1-4
GND U1-4
Same happens without slotting. However, if I take only one slot and
connect both Vcc and GND to the same pin 4, only one net remains:
GND U1-4
This suggests the pcb gnetlist backend (or maybe gnetlist) already uses a
per gschem-component identifier and refdes or refdes-pin doesn't fully
identify a component or a pin.
Regards,
Igor2
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