On Mon, 2011-01-03 at 16:04 -0800, Edward Hennessy wrote: > On Jan 3, 2011, at 8:20 AM, Stefan Salewski wrote: > > > I guess all this was discussed on the list multiple times in the past, > > so this is more a note to myself... > > > > I think it may be useful to have two types of symbols, soft and hard. > > Hard symbols have an footprint attribute and maybe additional hard > > properties. Soft symbols are simple an OpAmp or a resistor -- only type, > > no parameters defined. For schematic entry the use can select "Add soft > > symbol" or add hard symbol (if he exactly knows what he wants). If a > > schematic contains soft symbols, then there is an additional step > > necessary before PCB layout can start: Selecting footprints and slots -- > > this step may be supported by databases. (The user may have the optional > > choice to generate hard symbols from soft ones by specifying footprints > > and other hard facts in an early input stage.) > > Besides allowing attributes to contain a value representing unknown or > be empty, I don't see why the application needs to know the difference > between a hard and soft symbol. > > If the schematic editor allows empty attributes and allows the user > to edit these attributes, wouldn't it be capable of the functionality > requested above? >
At least the slotdef attribute is an example where we currently have to make a decision in an very early design stage. If I know that I may need some OpAmps or logic gates for my design, I may want to do not care about single, dual or quad packages when drawing the schematic. But currently we have to pick one of these types -- later we may have to replace it. For many tasks heavy/hard symbols may be fine -- when we know in advance what we need. But I really would like to have the ability to do a top down design: OpAmp -> VoltageFeedback -> FetInput -> Dual -> SOT8 Similar like selection at Digikey -- and now I remember postings of DJ, I really should read his http://www.delorie.com/pcb/component-dbs.html and try to understand it. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user