Long before computer CAD software, we used Symbol for the schematic, and footprint or package for the physical device. What is a good reason to go away from that?
Just my $0.02 Jean-Paul N1JPL > On Mar 23, 2017, at 2:02 PM, Heiko Rosemann <heiko.rosem...@web.de> wrote: > > I strongly believe that's because many people come from Eagle originally > (even via a different professional tool) and Eagle has this distinction. > A symbol is what you place in the schematic, a footprint is what you > place on the PCB and a component is what defines their relationship (and > links to a datasheet etc.). > > Example: A rectangle with three pins called VIN, GND and VOUT is a > symbol for a linear voltage regulator, could be called v-reg. The > footprint you choose for that symbol could be a TO220 with pads 1, 2, 3 > and heatsink, an SOT23 with pads 1, 2, 3, an SO8 with pads 1..8... > > The component "LM78Lxx" defines that for a variant LM78LxxACM, the > footprint is SO8 with Pad 1 used for Pin VOUT, Pads 2, 3, 6, 7 used for > Pin GND, Pad 8 used for Pin VIN and Pads 4 and 5 are Not Connect, for a > variant LM78LxxACZ, the footprint is TO92 with Pad 1 used for Pin VOUT, > Pad 2 used for Pin GND and Pad 3 used for Pin VIN. > > In KiCad, we have a mixture of "symbols" to which you can assign "any" > footprint and "components" which have a footprint specified, and we call > both "symbols". Some of these symbols have pin numbers called "1, 2, 3" > to fit certain "neutral" footprints, some have pin numbers called "VI, > VO, GND" to fit a certain "special" footprint, some have multiple pins > for the same function... the 78(L)xx-series in the libraries I got for > stable-4.05 is a good example of this mixture, and it used to be much > worse a few years ago. > > But then again, we have this discussion about once a year and it always > peters out after a while because nobody has the time to actually > implement a proof of concept (me included) so it can't properly be > evaluated, while the librarians do a great job improving the "standard > library" so people have it easier and easier to just use what's provided. > > (What I'd definitely love to see: A more prominent warning if your > symbol has some pins that don't have matching pads in the footprint you > have assigned them. Preferably in cvpcb or whatever dialog will replace > it, not 10 clicks later when you're importing a netlist into pcbnew.) > > Just my 2 cents, > Heiko > > On 03/23/2017 03:14 PM, Jon Evans wrote: >> I agree with Simon. I have plans to propose something like this in the >> future (i.e. an integrated part library that manages >> symbols/footprints/etc together) and it would be best to reserve the >> term "component" for this future use, since in my experience that's what >> "component" means in the big tools (I have not used Altium, but it is >> more of a "medium" tool than a "big" tool FWIW) >> >> I don't have time to detail my proposal now, but basically I think a >> "component" should map to one or more footprints, one or more symbols, >> one or more vendor part numbers, one or more 3D models, etc. >> >> -Jon >> >> On Thu, Mar 23, 2017 at 8:33 AM, Simon Wells <swel...@gmail.com >> <mailto:swel...@gmail.com>> wrote: >> >> one of the things that irks me about component is even though its >> meant to only be schematic being component libs a lot of the questions >> asked in irc will state component when they use that as either a >> generic term for symbols AND footprints or sometimes footprints only, >> as to some i guess thats still part of a "component definition". >> >> If at some point down the line we did introduce some sort of package >> that was symbol/footprint/model/spice/....... i think that would be a >> much better thing to call a component. >> > >> _______________________________________________ >> Mailing list: https://launchpad.net/~kicad-developers >> Post to : kicad-developers@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~kicad-developers >> More help : https://help.launchpad.net/ListHelp >> > > > -- > eMails verschlüsseln mit PGP - privacy is your right! > Mein PGP-Key zur Verifizierung: http://pgp.mit.edu > > > _______________________________________________ > Mailing list: https://launchpad.net/~kicad-developers > Post to : kicad-developers@lists.launchpad.net > Unsubscribe : https://launchpad.net/~kicad-developers > More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~kicad-developers Post to : kicad-developers@lists.launchpad.net Unsubscribe : https://launchpad.net/~kicad-developers More help : https://help.launchpad.net/ListHelp
