kicad-developers team mailing list archive

[Henner Zeller <h.zeller@xxxxxxx>]

On 5 June 2015 at 11:31, Wayne Stambaugh <stambaughw@xxxxxxxxx> wrote:
>
> On 6/5/2015 2:00 PM, Andy Peters wrote:
> >
> >> On Jun 4, 2015, at 9:26 PM, Chris Pavlina <pavlina.chris@xxxxxxxxx> wrote:
> >>
> >> The assignment of footprints to schematic symbols is largely a KiCad
> >> quirk. Many other tools consider a component to be a single package
> >> containing symbol and footprint. In my own library I have a part per
> >> actual electronic part (one called MMBT3904, for instance), which
> >> already has the Footprint field set from the very beginning, no mucking
> >> about with the nightmare that is cvpcb.
> >>
> >> Also, footprints are much more critical, in that you have to get all the
> >> dimensions very correct, so it makes much more sense in terms of being
> >> less error-prone to have multiple symbols linked to one footprint than
> >> one symbol linked to multiple footprints.
> >
> > At risk of reiterating myself again, what Chris describes above is how professional engineering groups do their libraries. Every company I’ve worked for has a vetted parts list and the PCB layout library includes only those parts. The symbols and footprints are married to a part number. Under no circumstance would someone choose, say, an NPN transistor from a library and then later match it to a footprint and to something that can be ordered. The chance of an expensive fuck-up happening is way too high.
> >
> > Pardon my Jersey.
> >
> > -a
>
> There is absolutely nothing preventing you from doing this.  The reason
> this isn't done is the list of transistor, op-amp, regulator, etc.
> symbols would be huge and a maintenance nightmare given our resource
> limitations.

+1

> The current symbol libraries are a good compromise.  There
> are really only a few variations for most 3 pin devices such as
> transistors and diode pairs.  Trying to provide a fully defined symbol
> for every transistor would be a huge under taking.  Our solution may not
> be ideal but I'm not sure I want to sift through thousands (tens of
> thousands?) of transistor part numbers to find what I'm looking for.  I
> wonder how well Henner's component chooser search code would handle that
> number of symbols.

Well, I wouldn't worry about that, I can make that fast :)

Main problem is, that it still takes the human to find longer if you
just browse. Also: overwhelming.
So this is only workable if there is some other layer of pre-filtering
(things available to me, available in my stash of components, company
stash of components etc).

-h

>
> That would probably take longer than just making
> sure my transistor symbol and footprint pin out are correct.  However,
> I'm betting if you would offer to do this, the library maintainers would
> not object.
>
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