Re: gEDA-user: Ideas for fixing slotting, methodology discussion, NOT implementation details!

[Bob Paddock <bob.paddock@xxxxxxxxx>]

> your idea of components being named with a
> manufacturer's base part number and then the packages identified by
> suffixes seems at the outset to be a pretty good one.

It is not a good idea.  Consider what happens
when one manufacture buys an other, and changes all
of the part numbers to their format.

We should not lose sight that a schematic is simply an
abstract representation of a physical object (that
may not yet exist).  We as designers are looking at
the schematic the most, but in the total life cycle of a product
it will be of little value to the business overall.  A product can
be built, for many years, without anyone ever looking at the
schematic, while many things change related to that product
over its life span.

Everything I've seen mentioned in this thread, about an 'other
file' or workflow, is done in the project Bill of Material (BOM) or
the Enterprise
Resource Planing (ERP) system.  It is absolutely *NEVER* done at
the schematic level.  [In a fully integrated manufacturing environment
all documents including the BOM, schematic, "Part Book", etc are a
subset of some
part of the ERP system.]

Consider you have "AVR1300" on your schematic and Atmel
does a die shrink and now their part is called "AVR1300A",
their DataFlash parts are already up to "D" BTW.

Purchasing: "I can't get AVR1300 anymore can I buy
AVR1300A instead?"

Me:  "After I get some samples and test it, yes, in
theory it is only a die shrink.  [Been down this road
simple "only a die shrinks" have made non-working
circuits for me in the past.].  AVR1300A is found to
work fine after due diligence testing.  So I change the
schematic.

Now simply adding this "A" requires that I regenerate the paper
work, get all of the approval signatures [call a meeting so
everyone is in one room at the same time rather then spend days
trying to find all of the people; then get yelled out for being
efficient], and resubmit the new paper work to someone like MSHA
where the fee is $800 for them to just open the envelope with the
new schematic in it.  FDA would cost even more...

Just to be clear here:  You absolutely positivity
do not want a down stream process reaching back up
to the schematic level.  It causes no end of "busy" work
and money spent for no gain at all.

>purchasing they might choose a footprint that constrained your choice.

If purchasing is making design decisions you have far bigger
issues to worry about than slotting.

-- 
http://www.wearablesmartsensors.com/
http://www.softwaresafety.net/
http://www.designer-iii.com/
http://www.unusualresearch.com/


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