kicad-developers team mailing list archive

[Karl Schmidt <karl@xxxxxxxxxxxx>]

Werner Almesberger wrote:
> Wayne Stambaugh wrote:
> > I like being able to embed this information into my schematics.
>
> I'm still puzzled what you're doing where this approach wouldn't
> turn into a nightmare before too long :)

Good points - but - to share some experience over some decades of using cad packages.  This messy
work with numbers that change HAS to be dealt with.  (It is one very good reason to have your own
part numbers that point to multiple manufactures.) It isn't trivial as Dick is noting.

In the early years - the CAD I used made a BOM that would spit out a list of reference and part
numbers - and nothing else. I remember writing some spread sheet kludge that would look up the part
number and fill in the fields and all. It was a terrible mess.

Later they added 'attributes' - AKA field names. During the design phase - some parts would get
different manufactures etc.. it always happens. I aways would update the library - in my old
software it would re-grab the parts every time the schematic loaded.

What could be added to kicad would be a way to re-grab all the fields from the library (perhaps
making updating the foot print optional?) - then the parts only need to be updated in one place -
the library?

When parts are out of stock, it pays to create an eco file to allow the second source - change the
info in the library and board and  increment the schematic revision number - and create a new BOM
with the same revision number. (The only issue is that if the buyer is working from a spread sheet -
they will end up creating notes that can get lost if they don't have good spread sheet skills).

My hope would be a distributed skeleton that includes some of these fields so libs are more
sharable. Every new part created would be populated with these field names and default values. The
user could change this skeleton.  The user can also add more fields as needed.

(BTW - I eventually moved to having separate parts for every value of resistor cap etc. One effect
is it helps reduce the number of unique parts that get specified. It also helps with using up
existing inventory - the reality is most boards don't really need 40 different resistor values that
you can end up with if just plugging in a value. )

The above may not make sense for a hobby board - but when dealing with boards with 300+ parts it
becomes critical. I remember nightmares that happened when a suitable system wasn't in place..


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Karl Schmidt                                  EMail Karl@xxxxxxxxxxxx
Transtronics, Inc.                              WEB http://xtronics.com
3209 West 9th Street                             Ph (785) 841-3089
Lawrence, KS 66049                              FAX (785) 841-0434

If you shake a politician's hand, be sure count your fingers.

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