Take a look at the following list of ERC errors:

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Why is Eagle CAD showing Warnings for the voltage supply connections? For example:

POWER pin U1 VIN connected to VBUS

I know these pins are connected to the correct supply voltage, so do I just approve them?


1 Answer 1


This is a stupidity of Eagle. Unfortunately you get these warnings when a supply pin is connected to a net with a different name than the pin.

Even worse, Eagle will implicitly connect a supply pin to a net of the same name. I and many other people, judging from the Cadsoft forums, think this is stupid too, but Cadsoft has so far refused to fix this.

Don't get the overall wrong impression of Eagle. It's a great package offered at a great price, and that's what I use too. Like any complicated piece of software, it has its quirks and some downright dumb choices.

A few other things to get used to: Lines are drawn with the WIRE command, except when they represent wires, then you use the NET command. CUT doesn't do a cut, but a copy, and COPY never seems to do anything useful.

  • \$\begingroup\$ Cool answer, Olin! I think the one thing that this does help with, is if one wants to do a double check and mark that pins are connected to the correct voltage supply on the design. I'll just go and approve these warnings. Thanks for answering! \$\endgroup\$ Jan 24, 2013 at 14:59
  • 1
    \$\begingroup\$ Automatic connecting of supply pins is why I don't mark any pins as supply in my components library, I just mark them as passives. \$\endgroup\$
    – Cano64
    Mar 27, 2015 at 16:57

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