How to re-annotate symbols with multiple units more easily? - Page 1
Forum section: electronics / general

author: ebastler
author_rank: Super Contributor
timestamp: May 29, 2021, 06:55:01 am
content: As one of the final steps before sending a PCB out for production, I often want to change the component numbering to make it more systematic. For devices with multiple sub-units (say the venerable 7400) I end up renumbering each gate individually in Eeschema, plus the separate power supply block. That is quite tedious and error-prone.There must be an easier way to do this which I am overlooking? Ideally I would want to re-number the parts in layout view (Pcbnew) and back-annotate. But a shortcut to renumber all units of a given part in Eeschema would also be very helpful. Thanks for any hints!(I did find this separate back-annotation software, but have not dared to use it. The version number 0.0.1 and the explicit "DO NOT USE IT" disclaimer in the readme file have scared me off... Has anybody put this to the test in earnest?https://github.com/weatherhead99/kicad_backannotate)

author: retiredfeline
author_rank: Frequent Contributor
timestamp: May 29, 2021, 07:24:22 am
content: You can select the symbol and edit the IC identifier (the U?) and edit the unit letter with the drop down and the pin numbers will change to match. It's up to you to make sure there are no clashes before you update the PCB. ERC will catch any errors.

author: ebastler
author_rank: Super Contributor
timestamp: May 29, 2021, 08:08:00 am
content: Sorry, I didn't make it clear enough what I want to do. I don't want to swap gates, but just change the reference number of the whole part. For example U15 shall be renamed to U20, for all four gates U15A .. U15D and the power block U15E.

author: julian1
author_rank: Frequent Contributor
timestamp: May 29, 2021, 09:05:20 am
content: Maybe the new geographic re-annotation feature in kicad 6,https://forum.kicad.info/t/kicad-6-geographical-reannotation/29314I have not tried it.

author: Kleinstein
author_rank: Super Contributor
timestamp: May 29, 2021, 09:29:55 am
content: With Kicad5 in the annotate dialog there is the option to also include the multi unit parts. It is usually important to not mix the units - so the middle option to reanotate all is dangerous as it also mixes different blocks like logic and power. The last option keeps the units intact.

author: ebastler
author_rank: Super Contributor
timestamp: May 29, 2021, 11:49:59 am
content: Automatic annotation typically does not work for me, since it is strictly based on the position of symbols in the schematic. For regular active parts and passives I am often uncertain whether I want the numbering to follow the schematic or the placement on the board. But nearly always there are at leastsomeparts which I definitely want to be numbered according to their positions on the PCB -- e.g. a row of switches and corresponding LEDs.Manual annotation is fine, but it would be great if I need to touch every part only once... Manual annotation in Pcbnew would be even better.The automatic "geographical annotation" in KiCad 6 is done from Pcbnew, right? So that implies that back-annotation will also be provided, i.e. I can also change annotations manually in Pcbnew and transfer them back to the schematic? I had not picked up on that, thanks! I don't think I am quite ready to switch my current board design to KiCad 6 yet -- it's a different file format, I understand?

author: retiredfeline
author_rank: Frequent Contributor
timestamp: May 29, 2021, 12:44:44 pm
content: Quote from: ebastler on May 29, 2021, 08:08:00 amI edit the part to change the number too, but I have to edit all the units of the part(s) so more work than you might like. I prefer my manual method because I'm fussy about the numbers and automatic numbering doesn't work for me. I'm in the habit of deliberately not using sequential numbers. For example if there are three sections in a design, I have no qualms about starting the numbering at 100, 200, and 300. And even leaving a gap say between 106 and 110 for finer classification. Nothing says that there must be no gaps in the numbering.

author: phil from seattle
author_rank: Super Contributor
timestamp: May 30, 2021, 05:57:59 pm
content: Quote from: ebastler on May 29, 2021, 11:49:59 amThis! I have a board with a couple hundred parts and really don't want to screw around with manual annotation. It looks unprofessional to my eye but I will live with it for now.Eagle has a plugin that allowed you to assign part numbers based on location on the PCB. It is a bit clumsy - doesn't allow that much control but got a lot close to what I wanted. I looked for a Kicad equivalent but did not find. Hoping KiCad 6 becomes ready for prime time soon. Not willing to jump before then because of the file-format one way door.