DJ Delorie wrote: >> 11. Several people are keen on the idea of changing everything to use a >> separate BOM as a master document. I don't understand what they heck >> they're >> talking about nor how it would work, so I would like them to spell it out >> carefully for stupid people like me. To me, a BOM is a spreadsheet, >> generated from the schematics, containing a list of refdeses and part >> information which is sent to an assembly house so they know which bits to >> put >> where. > > Right, that's what a BOM is. In our case, the BOM knows which > physical part is being used, so it can tell PCB what footprint to use, > and what the pin numbering is. That way, the schematics don't need to > know if I've chosen a TO220 or SOT23 regulator, which may have > different pin numberings. It can be told later, but at first it just > knows that the regulator has pins named "IN", "OUT", and "GND". The > BOM decides which physical part is used, so it can tell gschem that IN > is pin 1, OUT is pin 3, and GND is pin 2.
This concept includes one of Peter's wants, easy sharing of designs at any level of detail. Filing the attribs in a BOM file, (whether they are made available by a database engine or not), lets you easily chop off that file for sharing conceptual designs with the least extra detail. But back to "why the hell", a BOM is a natural world model that comes from experience, look how far Apple has come with that driver. Another way to say this is "make it intuitive". A BOM is part of making a circuit board. You don't leave it out without losing a lot. John G -- Ecosensory Austin TX _______________________________________________ geda-dev mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
