library - linking symbols to footprints - Page 1
Forum section: electronics / general

author: ron_l
author_rank: Newbie
timestamp: April 14, 2025, 03:23:14 pm
content: Having completed the intro to kicad where I made a symbol and then the corresponding footprint, I followed along and added the new component (switch) to the design exercise. Working on my own, I've made a new symbol and a new footprint. But I can't seem to be able to connect the two. What have I missed? It is not obvious to me where in the exercise the two (symbol and footprint) were connected.

author: PartialDischarge
author_rank: Super Contributor
timestamp: April 14, 2025, 04:56:50 pm
content: Edit the component in the schematic (hit E), and from there you can select the footprint from the libraries.Also in the symbol editor there is a panel accesible from the top icons where you can assign a footprint is that is always going to be the chosen one

author: ron_l
author_rank: Newbie
timestamp: April 14, 2025, 05:10:48 pm
content: Well that was easy enough.Thank you.

author: ron_l
author_rank: Newbie
timestamp: April 14, 2025, 05:13:13 pm
content: though... it is not without its errors. But I'm getting closer.

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2025, 06:14:39 pm
content: If you are setting this up from scratch, I highly recommend to use a database to create this linkage. Having footprints linked from symbols is not an easy way to work. Think about having lots of different resistors. With a database you define parts like a resistor as a value, type, manufacturer, order number, etc, plus the symbol and footprint. This allows much more flexible re-use of symbols and footprints. For example chips in different packages. One symbol can be used for 3 different parts, each with different footprints and order codes. Another advantage of a database driven setup is that you can create a correct BOM very easely. Gone are the days of doing tedious work on adding order codes or looking up parts one by one to complete a BOM. The key thing to understand that a symbol isn't a part!

author: Benta
author_rank: Super Contributor
timestamp: April 14, 2025, 09:56:50 pm
content: Quote from: nctnico on April 14, 2025, 06:14:39 pmWell put!The other thing to understand is, that the symbol is the top level (the master), to which you can attach footprints, Spice models, datasheet etc.It's not a question of linking them together.

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2025, 10:31:11 pm
content: Quote from: Benta on April 14, 2025, 09:56:50 pmFixed that for youSorry, I'm in a nitpicking mood.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: April 15, 2025, 12:47:44 am
content: Quote from: nctnico on April 14, 2025, 10:31:11 pmThe "traditional" way in KiCad is that symbols and footprints are separate items. There is no real "part", and a symbol can have an (optional) link to a footprint.For your "nitpicking" part. In your previous post you mention the database driven system. This is much closer to having a "part" to which a symbol and a footprint can be added. I have not used the database system in KiCad yet myself. The "traditional" system works quite well for occasional projects and hobby use of KiCad. The database driven system is more complex, but has advantages as it can be combined with other info such as ordering info (inclusive alternatives from different part vendors) and all sorts of other data that can be put into a database.The database itself is not a part of KiCad, KiCad just has an interface to work with a database. This adds some more complexity (You have to set up the database yourself), but it also has a lot of flexibility. You can for example couple an already existing database (for example made for another EDA suite) to KiCad, and then just keep on using your database with known vetted parts in KiCad too.

author: SiliconWizard
author_rank: Super Contributor
timestamp: April 15, 2025, 02:12:07 pm
content: Except for "generic" symbols, all symbols that are specific to a specific part in KiCad already have the footprint defined inside the symbol properties and when you start using your own libraries, you should do the same.Refrain from modifying standard KiCad libraries though - make your own. Otherwise you won't like it when you update KiCad.

author: Benta
author_rank: Super Contributor
timestamp: April 15, 2025, 03:45:15 pm
content: Quote from: SiliconWizard on April 15, 2025, 02:12:07 pmActually that's not even possible. The standard libraries are read-only.

author: PartialDischarge
author_rank: Super Contributor
timestamp: April 15, 2025, 04:33:32 pm
content: Quote from: Benta on April 15, 2025, 03:45:15 pmI can edit the symbols and footprints of the libraries that came with Kicad. But I have version 6 with local copies of them.

author: Benta
author_rank: Super Contributor
timestamp: April 15, 2025, 06:20:31 pm
content: I don't remember how it was with 6.But yes, you can edit the libraries. The problem comes when you try to save your edits.