Electrical Rule Check Error Pins of type Power input and Unspecific are connected

[PCBrain]

I’ve been creating multiple schematics using Kicad 5. But I’m new to Kicad 6, which has a lot of improvements as far as I figured out.
But I cannot run a proper ERC.
I always do get this issue on nearly every GND connection:

“Electrical Rule Check Error
Pins of type Power input and Unspecific are connected”

[PCBrain]

My pins (in this case on an Arduino Mega2560 if this matters…) are ground pins. And they are connected to ground…so what might be wrong with it?

[PCBrain]

[mf_ibfeew]

My pins (in this case on an Arduino Mega2560 if this matters…) are ground pins. And they are connected to ground…so what might be wrong with it?

You have to learn how the ERC works:

• The ERC consists of many different tests for specific aspects of the schematic
• If a ERC-test shows a message this is not proof that there is something wrong - it shows only that the test-constraints are violated
• So to judge the ERC-messages it is necessary to know what every ERC-test does.

In your case the ERC complains about pin type mismatch. For this test the ERC checks all connected pins and their pin-type (defined in the symbol-editor). The ERC looks into the Pin conflicts map (see schematic Setup → Electrical Rules → Pin conflicts) which pins are allowed to connect. (for instance it’s forbidden to connect two output-pins together). All connections with a forbidden pin-combination are reported.

In your case not only the GND-pins of the 2560 are connected to GND, but also other pins (from other symbols) somewhere else on the schematic. At least one of these many GND-connected pins contains the “unspecified”-setting for the “Electrical pin type”.
A look into the pin conflicts map: connection “unspecified pin” connected to “power input pin” (== your 2560GND pins) → ERC-warning -message.

This is not the end of the world, if you know what you do you can ignore this warning.
But you can also search for the symbol/pin with the “unspecified”-setting and correct this. The ERC is not able to work with this setting → hence the warning.

[PCBrain]

Well, good to know. I thought this Marker is specific for this part/microcontroller.
So I’m going to check everything else

I’ve been doing the ERC for all of my latest PCBs and never had an error I couldn’t solve. It gives me a good feeling if the ERC displays no errors - tough I know what I do.

[mf_ibfeew]

If you click directly on the message-lines in the ERC-window the view will scroll&center on the affected pin. (Maybe you need to adapt the zoom-factor prior).
So you have not to search through all symbols/pins of your schematic to find “unspecified”-pin…

[PCBrain]

That doesn’t work. As it affects the Gnd symbol, it also affects switches, capacitors, microcontrollers… I figured out that my switch (which is used more than 20 times in this project) had an undefined pin.

But then I run into library-management problems, as I copied the project from my other computer (which is at home) to my laptop (which I have here in my hotel room) and migrated from Kicad 5 to Kicad 6 - but the library was a write-protected rescue lib…
I guess it’ll be a lot of work to get this project up and running properly… Also I have to figure out the changes in Kicad 6

The good thing is I didn’t migrate a customer’s project, this one is going to be an open source Arduino Midi merger/splitter project, so I don’t have to worry too much. If I can’t get it work properly, I can start from the beginning (and run ERC regularly to see when an error occurs).