pcb-rnd knowledge pool

 

Index: using and creating footprints

Ifootprint by Tibor 'Igor2' Palinkas on 2017-12-25

Tags: index, footprint, library, lib, subcircuit

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Abstract: n/a

 

Using existing footprints

Using footprints has three main aspects: library (how/where to get the footprints) and importing from schematics .

Library

Pcb-rnd has a modularized library support: differnet fp_ plugins access local and remote footprint libraries differenlty. At the end all footprints are accessible through a unified runtime library. Related nodes:

Importing from schematics

When a raw netlist is imported, no footprints are placed, only the netlist is initialized. In an "import schematics", both netlist and footprint data is imported.

How to design footprints

Technically

Drawing a footprint is creating a subcircuits . A subcircuit is a generic grouping mechanism that is also used as the footprint implementation in pcb-rnd. Related nodes:

Details to consider

There are a lot of fine details to consider when designing a footprint:

Terminals can be numbered by hand, using the {e t} keys over the terminal, or using scripts such as the termnum script, available from edakrill.

Padstack design

Terminals of a footprint is most commonly created using padstacks. Padstacks are constructed and broken up in a very similar way to subcircuits.

When designing a padstack, you should consider: