checks for slotted parts and large parts

[danmc]

There was recently a discussion on one of the mailing
lists about symbols for large pin count parts. One
proposal is to break these into multiple symbols. This
applies to small but multi function chips. For
example, a dual op-amp might want to be broken into:

myamp-1.sym -- channel #1
myamp-2.sym -- channel #2
myamp-3.sym -- power pins

It seems like something useful is to have an additional
attribute to indicate that this is a "multi-symbol
part" and which piece each symbol is. For example,

myamp-1.sym -- multi=3, multicnt=1
myamp-2.sym -- multi=3, multicnt=2
myamp-3.sym -- multi=3, multicnt=3

and now include a check in gnetlist (drc2 backend
maybe, maybe globally for all backends) that ensures
you have instantiated all (3 in this case) pieces of a
part. This will avoid forgetting to instantiate the
power/ground symbol for a part or tying off unused
gates in a multi-gate symbol.

[KaiMartin (kmk-familieknaak)]

While this approach solves the immediate need, I see some issues:

* There is no place to look a comprehensive list of symbols that make a part.
People and applications would have to scan the lib to collect them all.

* There is much room for inconsistency.

* How about cases where not all parts are mandatory, or some symbols are alternative?

* How would a power symbol for 74er components serve all different gate components?

Bottom line: Although I have filed a similar proposal (https://bugs.launchpad.net/bugs/698818 ),
I now think, the issue should be treated differently. It could be resolved with the notion of
packages, like in other EDA suits. A package would be a container for all the information
that makes up a part -- symbols, footprints, comments, documentation and even notes.

---<)kaimartin(>---