[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: gEDA-user: Reinventing the wheel

On Thu, 19 May 2011 08:36:50 -0600
John Doty <jpd@xxxxxxxxx> wrote:

> On May 19, 2011, at 8:21 AM, Kai-Martin Knaak wrote:
> > Vanessa Ezekowitz wrote:
> > 
> >> KMK didn't say what he means by "unusable", 
> > 
> > Most immediately: The symbols in the default lib do not contain footprint 
> > attributes. Not even an empty ones. This prevents them to "just-work" for 
> > the most common work-flow of geda: gschem -> gnetlist -> pcb -> gerbv 
> What's the footprint for a transistor? A resistor? A 7400? All of these
> come in many packages and many also expect a 1:1 mapping from package to
> footprint, but that isn't how it works.

But that *is* how it works - to a new user or a seasoned user, ultimately footprint = package.  We've had this discussion before, and the answer is clear:

Choose some reasonable defaults that will work for the majority of use cases.  Through hole or large gauge SMT unless there is no other option, and using the most commonly available parts.

If a person instantiates a transistor, give it a TO92-3 footprint (though I prefer TO-18 for its retro look).

Resistors?  I use a footprint I created that fits 1/8 and 1/4W and folds the resistor in half to save board space.

Resistor packs?  Use whatever SIPx footprint fits the part.

Signal diodes like a 1N914?  Same footprint (just tweak the drill diameter for thick-leaded parts like 1N4001)

Capacitors?  I use one I made with 200 mil lead spacing and about 50 mil width for ceramics, and the default ACY100 for electrolytics.

ICs?  Use an SOIC footprint unless the part only comes in some other form.

IC sockets?  Obvious - use a DIP footprint.

The above probably covers 90% of use-cases, and besides, the user probably needs to be able to hand-assemble their creations initially (prototypes before a production run), and you can't do that if the initial board is covered in 0603, TSSOP, BGA, and similar parts, and/or parts of any kind that have to be bought at some only-sells-1000-at-a-time distributor.

> > ack. 
> > The historically grown structure is less than stellar. And the scope needs
> > to be reduced to what can sensibly be delivered. The libs should not
> > suggest completeness where thay can only provide a (good) starting point. 
> It isn't so much the libs, as the lib browser, which sends the selected
> part straight to the schematic, thus giving the user the false impression
> that they're finished with it.

What's needed here is a minimal attribute editor right in the library browser window.  Click a symbol, and the bottom of the window expands to show the most important attributes of the symbol: refdes, footprint, slot# if applicable.  Click again in the schematic window and the symbol is placed with whatever attributes have been set.

"There are some things in life worth obsessing over. ÂMost
things aren't, and when you learn that, life improves."
Vanessa Ezekowitz <vanessaezekowitz@xxxxxxxxx>

geda-user mailing list