kicad-developers team mailing list archive

[Andy Peters <devel@xxxxxxxxx>]

> On Mar 30, 2016, at 4:22 AM, Paul LeoNerd Evans <leonerd@xxxxxxxxxxxxxx> wrote:
> 
> 
> Should I
> 
>  A) Make a single schematic library symbol for a generic "DC-DC
>     converter" whose pin names are IN- IN+ OUT- OUT+ and two
>     different footprints whose pin names match.
> 
>  B) Make two schematic library symbols with named (or numbered) pins,
>     one associated with each footprint?

In professional organizations, option B is pretty much always used. 

You don’t place _symbols_ on a schematic sheet. You place _components_. What is the difference?

The former isn’t very smart. There is nothing stopping you from putting a generic NPN on the schematic, and then choosing a footprint later. And then when it comes time to buy parts, you have to remember exactly which NPN transistor you want.

When you place a component on the schematic, all at once you are indicating the footprint for the layout and a unique part number so you know what you are buying. And, ideally, you are using a vetted company library. 

The time spent setting up the vetted library with proper components is saved when you go to actually use the components in a design. You set up the library exactly once, and then you never have to worry about matching footprints to symbols and part numbers ever again.

if you want an OPA552PA on your board, you place an OPA551PA from your library. If you decide later that you want the OPA551PA, you simply update the schematic by pulling the new part from the library and changing all of the parts in question. Then regenerate a netlist and import into pcbnew. Now your BOM remains in sync with the board.

If you want the surface-mount OPA551UA instead of the through-hole OPA552PA, again, pull the desired part from the library, update the netlist, bring it into the layout, and let pcbnew change the footprint. And, again, the BOM remains in sync with the layout.

I honestly don’t understand why some people think that setting this up is “too difficult."

-a