About power input/output

I hereby certify that I am not simply asking someone else to design a footprint for me.

This is an auto-generated message that is in place on the “footprints” section of the KiCad.info forum. If I remove it and ask for a footprint to be designed anyway, I understand that I will be subject to forum members telling me to go design my own footprint or referring me to a 3rd party footprint site.

Hi everybody !

I am switching from Eagle (I have been hating since the begining…) to KiCad, and I’m re-disigning my entire symbols/footprints libraries from scratch + adding self made 3D models. As a training and because I like it. (I konw of utilities that do it, but no !)

I have a problem I can’t get much information about. I mostly play with arduino’s and STM32’s (Nano’s, ProMini’s BluePill’s, BlackPill’s). I made 3D models, footpints, etc. But I have a problem with power pins. On such modules some power pins can be inputs, and/or outputs. For example RAW/5V/3V3. What attribute should I use ? Bidirectionnal ? Power could come from RAW, 5V or 3V3, or RAW, go to 5V and 3V3 and be used by other components in the schematics… ERC is not happy !

What is the best way to design the components ? Google didn’t help that much with keywords such as "KiCad, power, pins, output, input, and so on…)

I know of the KLC, and it is in my fovourites.

You already know Electrical type of schematic symbol pins (KiCad 4 and KiCad 5)?

KiCad 5 doesn’t handle alternative pin functions. 5.99, in the future 6.0, handles them with alternative types. ATM I think you have only a couple of workarounds, for example having several symbols for different needs, changing the type to passive (which is compatible with other types for ERC), or ignoring the ERC error.

BTW, your post is in Footprints while we are talking about symbols which belong to Schematic -> Library Symbols.

Thanks !

Passsive seems to be the simplest. 6.0 candidate 1 comming soon, I downloaded last 5.99 nightly build, and will give it a try. I can’t wait because of the pin stacking !

And sorry for posting in the wrong section ; bad habbits from Eagle where symbols and footprints are in the same library…

Think twice before you start with 5.99 now
It’s in a very unstable state at the moment, and stuff you do with it is very likely not compatible with KiCad V5.
Don’t just get tempted by the usual “higher numbers are better”.


Personally I would make them all Power Input type pins. If you plan on using one of those pins as a power output pin on a particular design I would put the PWR_FLAG symbol next to the pin you plan on using as an output. That way you keep your module symbol general purpose and you can use the PWR_FLAG symbol as an indicator when reading your schematic as to where the power is flowing from.

This is one way of skinning this particular cat. It isn’t necessarily better or worse than others, but it is how I would do it. (Granted, I even use Power Input type pins on the output of voltage regulators and batteries so my usage of the PWR_FLAG symbol is consistent…)

“Passive” makes the symbol easier to use. “Power input” requires the power flag but makes the schematic more consistant… Cornelian dilemma !
The reason why I was asking this is because I created a little lib for blue pills and black pills I shared on my Git (https://github.com/yet-another-average-joe/Kicad-STM32). Later, reading the KLC more in depth, I realized I made some mistakes ; I’d like it to be as KLC conmpliant as possible. I also don’t know how to make user friendly symbols with stacked pins : the KLC says that the problem will be addressed with KiCad 6.0 : this is why I wanted to test 5.99. I run it in a VM for testing purpose, not on my real PC. But I didn’t find information about the new feature (maybe it is not implementaed at this time…). Many threads to read !

Hi, Paulvdh

I generally agree with the warning about the nightlies, but I got myself stuck in them months ago and then I came out of retirement. I did update a few times due to bugs not so long ago. But the particular build I am using now seems to be giving me very little trouble. (He said before his head fell off.) So if someone has committed himself or herself to the nightlies and have too many bugs hitting your face, try this Windows build from August 21:


One caveat: I have not bothered with 3D…

I wasn’t really intending to use nightly builds ; nighly builds are not for beginers. I was just looking for new features replacing pin stacking. Something equivalent to the ‘@’ suffix in Eagle pin naming (interconnected pins in devices/modules). But I can live without. So much that when I reopened it after one year, I found Eagle even more difficult to use that it was when I first installed it 10+ years ago ! This is weird. A couple years ago I attempted to use KiCad, and couldn’t understand libray management. I gave up and went back to Eagle. Now, it is the opposite. Probably never will look back.

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When I started with KiCad I read about using GIT for version control. I think that KiCad is not so difficult but I never did figure out GIT and gave up on that. My present method is to include a date/version letter in the (file names = folder names; all the same) and regularly copy/rename the folder and file names. This has worked well for me. I have only used global libraries and have not used project specific ones although I don’t see a problem doing that.

An important way that I like the nightly better than stable release is that when I select a portion of the schematic, that selected portion gets highlighted. This is very helpful and was not the case with the last stable release version that I used.

I also have problems with Git (desktop, and I didn’t even try the command line): as a result, I upload files directly. Not the best way to use it !
From time to time I play with the nightly I installed in a VM. Yes, the cpy/paste for schematics portions is great ! I was also very pleased to find polygonal (chamfered) pads. Hope they will add octogonal pads in the dropbox so there will be no chamfer parameters to enter : they are better for those who etch their PCBs (and Elektor/Elektuur readers can’t live without !). Also hope they will add teardrops (seems to me there’s a plugin…)

I guess this discussion is veering to a new topic…

Using a virtual machine; you are over my head (at least I know the abbreviation.)

Do you copy/paste schematic portions between two different schematics? I don’t think I have tried that. A brief description would be helpful.

What is the advantage of chamfered or polygonal pads over round ones? How about starfish shaped pads? (I am kidding.)

VM are easy ! More easy than real ones ! (just try VirtualBox or VMWare). VM’s have been around for 20-25 years, and also came with Windows7 as “Mode XP”. They were also used for cross development under Windows CE/Mobile, and are probably for Android (never coded for Android…). It’s really handy when you want to try some software but don’t want to really install it on your computer for some reason (untrusted sources for example). It’s also handy when you want to use one software with one environment on different machines and different OSes. It is often the only way to go for older softwares : can’t run an old 16bit software under W10 64bit ? Just install a 32bit OS in a VM, or even DOS and Win 3 !

Copy/paste : I didn’t try nighly build extensively, because I’m recreating all my custom footprints for KiCad, + drawing 3D models. Very time consuming, and don’t want to use any utility to do it. Good way to learn KiCad.

Octogonal pads offer a bit more surface, relative to round ones with the same diameter : better adhesion to the substrate (more surface for the same diameter and the same clearances). It makes a difference for single sided PCBs, particularly if etching is made at home after laser transfer. In theory, they will create a few more acid traps, but I never had such problems. Probably no difference or very little with double sided / metallized holes. Some like them for their aesthetics (I do). Always loved the '80 Elektor PCBs style. I have all my customized footprints with octogonal and oval pads in Eagle (until now I always made my PCBs at home).

I run 32 bit Protel 3 at old PC with Windows XP I left only for that one program. Do you know if I am allowed to install that Windows XP at VM at my PC with Windows 7 (never tried VM)?
As I understand Win XP is licensed to that old hardware. I have heared that licence can go with any part of hardware - like mouse. But my Win 7 PC had not got even right mouse socket (only USB ones).

Go to Microsoft website, download XP Mode, install it. AFAIR anyone is allowed to install this XP virtual machine in Windows 7 (it is an optional part of Win7, it was made for people who couldn’t run older softwares directly on Win7). I don’t remember exactly how it is integrated, but it seems to me that you run XP softwares within Win7, as if they were Win7 softwares (desktop integration). I don’t remember about the BIOS, but you could have to activate some virtualization options (give direct access to the processor and other resources).

Doing this you should be able to run Protel in Windows 7. I don’t have Protel, and my only Win7 machine is a headless NAS, so I can’t even test XP Mode…

You can install your existing XP media in a VM using the product key you have and copy your program across.

Or you can find an XP Pro image at archive.org with a working key. Microsoft has abandoned XP so anybody can install it for free.

The VM will see a virtual mouse so it doesn’t matter what kind of physical mouse it is.