kicad-lib-committers team mailing list archive

[Bernd Wiebus <bernd.wiebus@xxxxxx>]

Hello Qichang Liang.


> - Also are there plans to create a new object class "component" that
> map a symbol to one or more packages?
> 
> This will make the workflow from schematics to PCB much easier
> 

I hope not, because i like the way kicad handels this "problem".

As an example, look at the way, like it eagle does. You neet a component
library for every transistor multiplicated with the number of different
footprint styles you use and perhaps multiplicated with the number of
different schematic styles.

Perhaps you use eight different transistors like BC337, BC369, BC517,
BC567, BC556, BC557A, BC557B and BC558, all PNP. Then you have perhaps
eight different footprint styles:
inline small with small pads, inline wide withs small pads, crooked
small with small pads, crooked wide with small pads, inline small with
big pads, inline wide withs big pads, crooked small with big pads, and
crooked wide with big pads. 

That means, you have 8x8 = 64 components in your library. An you can
make schematics in the american NEMA style or the european EN60617
style. This would mean, you have 128 components in your component
library.

In Kicad you choose the build in NEMA symbols or the EN/DIN60617 symbols
from the contrib folder. Then you have only one symbol for a PNP
transistor. Then you choose at CvPcb from eight different footprints.
Thats all. To specify a special transistor like BC337 means only to
write BC337 into the schematic.

If you change the transistor without changing type or footprint, you
only have to write another type into the schematic. If you change the
footprint, you have only to change the footprint in cvpcb and connect it
in pcbnew again.

So its easy to change from BC337 (TO-92) to BC856 (SOT23). Just write
BC856 instead of BC337, and change footprint from a TO-92 variant into a
SOT23 variant at cvpcb. Then reconnect at pcbnew (which generally is the
most work).

I like the way of kicad. A strict connection between symbol and
footprints means only big bloated labyrintic librarys. 
In kicad, i can work like an artist, choosing symbols and footprints
free like colours from a palette. ;-)

Maybe transistor manufacturers hate this way, because they cannot
present you a special TRxxxabc footprint for advertising. ;O)


With best regards: Bernd Wiebus alias dl1eic
http://www.dl0dg.de