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I finally finished my first schematic and everything looked great. I went ahead to perform Electrical Rules Check.

There were many errors.

Most of them were:

Pin connected to other pins, but not driven by any pin.

Pin not connected (use a “No-connection” flag to suppress this error).

I used bi-directional pins exclusively.

Also note that I used the Arduino shield template. Maybe I had to declare all pins not used as NC?

If you want, I can upload the schematic file somewhere.

Here is a picture of the schematic:

enter image description here

My questions are these:

  1. I get that i should put the NC to all the pins not connected, on the arduino header pins to the right. But what about those that have a name on them like IOREF, +3.3V, +5V, Vin etc? What do i put on these?

  2. Is it ok if i leave the pins bidirectional?

  3. Should i put only two power tags? One for Vin at the power jack, and one at GND at power jack? Is this correct?

EDIT: enter image description here

user1584421
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    your post is unrelated to the Arduino, so it is off topic here – jsotola Nov 19 '20 at 02:20
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    We are experts with Arduino, not with KiCad errors. So maybe you would be better of at Electrical Stackexchange. I surely cannot answer your question. –  Nov 19 '20 at 08:10
  • Thanks guys. Actually i posted on electronics stackexchange first. But as for ALL the arduino pins have the NC flag, they weren't sure, so they told me to post over here for this detail. – user1584421 Nov 19 '20 at 10:19

1 Answers1

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  1. Yes, all unused ports should have the NC symbol.
  2. Yes, it is only a warning, check for yourself that not both ends of a signal are for input only (or output only).
  3. You can use as many power symbols (like the GND and +5V symbol) as you want, but you need to add PWR_FLAG symbols to to of them, like an example below.

enter image description here

Michel Keijzers
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  • Thank you very much! But about the answer (3).. What did you mean with "you need to add PWR_FLAG symbols to two of them"? I didn't get what do you mean with 'two of them'. Are you referring to the two lines that come out of the power jack? Where the one is the power, the other is ground? (The power jack is located in the upper portion of the center of the image) – user1584421 Nov 19 '20 at 10:22
  • @user1584421 I updated the answer, I think you have to put them on both 3.3V, 5V and GND. – Michel Keijzers Nov 19 '20 at 10:34
  • Hmmm, all three chips are fed 5V from the power jack. So i don't think there is any 3.3V source to place the flag on it. One last thing: I won't have a problem if i place the NC tag on arduino pins that have a label right? Like IOREF, 5V, 3.3V, Vin etc, is this correct? – user1584421 Nov 19 '20 at 10:42
  • I now see you don't use the 3.3V, and yes, you can put all NC's to it. – Michel Keijzers Nov 19 '20 at 10:49
  • Thank you very much! I will report my progress with your recommendations. – user1584421 Nov 19 '20 at 10:57
  • Good luck with your project – Michel Keijzers Nov 19 '20 at 11:05
  • For the arduino pins that connect to 5V, and 3.3V by default (by the template) it gives me: "A pin with a no connection flag is connected". I updated the question with an image to make it easier to check these two pins out. – user1584421 Nov 19 '20 at 11:38
  • Yes that seems a bit odd. But where does the +5V come from? It seems you need to connect it (and add the PWR_FLAG) – Michel Keijzers Nov 19 '20 at 11:44
  • The 5V and 3.3V came from the arduino template. When you load an empty arduino template it is offered like that. However, i do not make use of these pins in my circuit. But these pins will be connected to the arduino's power rail, since the male header pins of the shield will be inserted in the female header pins of the arduino. Do you think i should deleted these 5V, and 3.3V tags and lines that KiCAD generated automatically, for the arduino template, and just put a NC tag? – user1584421 Nov 19 '20 at 11:49
  • It's a bit long time ago I used KiCad, but if you don't use the pins in your project, you can delete them and put NC tags on them. – Michel Keijzers Nov 19 '20 at 12:25