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Re: gEDA-user: multi-part symbols [was: OGDI]



May I make an alternate suggestion here?

The "slot" mechanism is for identical internal subsystems within a part. I propose keeping it that way: I think any attempt to extend it to heterogeneous internal subsystems is likely to make a confusing mess. It's already confusing enough!

Instead I propose adding the concept of "subdevice", supported by attributes "subdevice" and "others". For example a 7400 gate symbol might have the attributes:

device=sn7400
numslots=4	(with the usual other slotting attributes)
subdevice=1
others=sn74pwr14

There would be a generic power symbol for a 14 pin TTL package with attributes:

device=sn74pwr14
numslots=0
subdevice=1
footprint=DIP14

Thus a full 7400 package would be represented by four sn7400 instances plus one sn74pwr14 instance. The "subdevice=1" attribute without "others" would tell gnetlist to warn the user if the symbol is an orphan without other subdevices with the same refdes (this is for generic subdevices like the sn74pwr14 where the other associated subdevices may vary). The "subdevice=1" with "others" would tell gnetlist specifically what other subdevices are needed to make a complete device. If any is missing, gnetlist could issue an appropriate warning.

Having the footprint associated with the generic power subdevice in this case would make it easier to change package technologies for a whole family: just make up a new symbol with device=sn74pwr14 and the correct footprint.

John Doty              Noqsi Aerospace, Ltd.
jpd@xxxxxxxxxxxxx