[gta02-core] KiCad wish list

Rene Harder rehar at saweb.de
Mon Jun 15 20:55:35 CEST 2009

Werner Almesberger wrote:
> KiCad lets you do about half of this: I think you should be able to
> define pin "numbers" by name in both the component and the footprint.

How can you do this with Kicad, I was looking for this function quite
some time but could not find a way to do it.

> However, then you'd get a function-specific footprint (e.g., a
> SOT-323 for BJTs with pads labeled B, C, E), which isn't so nice.
Why do you think that's not nice, I prefer labels with B, C, E, because
then I know the function immediately without checking the data sheet.
Not all symbols are as easy to understand as a transistor but usually a
pin is named after its function which makes it easy to understand.

I think we would benefit way more from a function-specific footprint.
The function of one pin (at least in one device group, e.g. transistors)
doesn't change much with different vendors but pin numbers and
footprints do.
Remember our problem with the dtc123 transistor, there are many vendors
with different pin numbers and footprint but the pin labels were almost
the same.
Some called them B,C and E others IN,OUT and GND however if you would
name the pin B,C and E everyone who sees the symbol would associate
B=IN, C=OUT E=GND. If you now could link the pins by their name to the
pin in the footprint (even vendor specific footprints) I don't think
anyone would get confused by it.

> Having KiCad know about a mapping (if one exists) is an interesting
> idea. That would also allow you to show the real pin/pad numbers in
> the schematics, while keeping the symbolic pin "numbers" inside.
> (In fact, maybe just do away with the pin numbers, and use the pin
> names as a key for the map. That would remove one level of
> indirection.)

Well that's exactly what the device layer should do (or does in eagle).
You have a symbol with function specific names, and footprints with
vendor specific numbers the device layer links function of the symbol to
vendor specific pin number. For each device you can add a vendor
specific description and and a package specific suffix.

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