Ardunio UNO R3 Template - Connecting to 3.3 and 5 volt Pins


#1

I am new to KiCad and I am hoping someone can help with this question.
I am using the Arduino UNO R3 template to place components onto this shield. I have two components on the board, one uses 3.3volts and the other 5volts. When I try to wire or use labels to connect to the points on the Arduino Template, I am not able to do so. To work around this, in PCB new, I disabled the enforcement of design rules when routing and manually route the components to the proper voltage. I should mention I am using version 4 of KiCad.

Is there a way to make the connections to the appropriate voltage pin on the Template in the Schematic layout Editor.

Thank you in advance for your help.


#2

Could you provide more details on what exactly you’re trying to do and achieve?
What is the “Arduino template”? Is it template for the PCB, or a “Framework schematic” with PCB?
Basically what you need is to have a proper, ERC-error-free schematic and a netlist generated upon this schematic. This netlist is then used for the PCB part to determine proper connection between pads (generally each component pin in the schematic is represented by one or more pads in the PCB).
Until you have the netlist connections defined, the PCB will refuse to connect the tracks with DRC enforcement ON.


#3

I’ve got KiCad V5.0.2 with maybe some “Extra’s” and I found the file:

/usr/share/kicad/template/Arduino_Uno_R3/Arduino_Uno.pro

I opened it in KiCad. It has an Eeschema with the connecor layout and a pcb file with the layout of an arduino board.

I’m also a bit confused to the intention of Larry23.
I added 2 resistors to the schematic. One between 5V and GND, and the other between 3V3 and GND:

Assigned footprints for the resistors, annotated & imported & routed them in Pcbnew:

All looks well.


#4

Paul

I think I see why I am having a problem. Shown below is how I have been trying to add the pin label to my components. I see you are using arrows in your schematic. Can you tell me how I can get arrows to show for the labels. I am pretty new at this.

Thank you very much.


#5

Easy answer for this instance. Copy (called “Duplicate” in the context menu and keyboard shortcut “c”, case insensitive) the existing power symbols (the arrows you are referring to).

Longer answer is to use the “Place Power Port” right-side toolbar button (looks like a ground symbol) and find the exact power port symbol as is used in the schematic. You could also place a regular component and pull from the Power library (the place power port tool is basically a filtered place component tool).


#6

SembazuruCDE hit the nail on it’s head.

It seems you have drawn local labels with text. These can be used to connect 2 wires together if you give them the same name, but for power there are the power symbols.

I simply hoved over the existing symbol (with arrow) and pressed “c” to copy it.
This is an easy tric for resistors and capacitors also:
First add a resistor to your PCB, and then assign a Footprint (SMT or THT). Then make copies for the other resistors, and they will all have the same Footprint.
(But in the newest version of KiCad this is much less of an issue)
But I’m getting sicetracked here.

Another way to easily add your power symbol is to press "a"dd in your schematic and then typ “3.3” (Without quotes) in the search box. This will give you an overview of all schematic symbols which contain the string “3.3”. Then you can select the right one with the mouse.

I had never used the “Place Power Port” SembazuruCDE mentiones, but I just tried it and it also seems to work.

Another tip:
Always draw the green wires between 2 symbols for connections.
The second icon from the top on the right toolbar is a “highlight net” function, and you can use this to check if KiCad knows if the connections you want to make are connected properly.


#7

The actual reasoning for this is how KiCad internally represents different types of labels. Local labels have the sheet name added before it (internally, the only way you will see this is by looking at the netlist or the netnames in PCBNew), even on single page schematics. Power symbols use global labels. Global labels don’t have any sheet name added before the user given name. So, KiCad won’t connect “Sheet1/+3.3V” to “+3.3V”. That said, one could use create a global label called “+3.3V” and it will electrically connect to the “+3.3V” power symbol. I wouldn’t advise doing that (it would get confusing because the global label looks different then the power symbol so the connection isn’t immediately obvious), but it should work.

P.S. I may have my example not entirely accurate, but the theory is sound.


#8

Tnx for the explanation, just learned something.
I’m not up to date with KiCad V5 yet.
A long time ago (KiCad V3?) I used to ignore all the power symbols and made my own. It looked exactly like a power symbol, but I could edit the name and that would be attached as a label to the connected wire. This was pretty handy when I had some isolated power supplies with the same voltages once.


#9

Chris

Thank you very much for your help. Everything looks good on the PCB board and now I can use an auto-router that I just found from an Instructor on Udemy.com. Prior to this, I had to manually add the tracks for the power inputs.

Thanks again. Just an old retiree trying to learn something new!!


#10

Paul

Thank you very much for your help. I did what you suggested and added the power symbols from the drop down for the schematic. Although I still get DRC errors indicating an Error 3 with no pin to drive the power pins, if I ignore the errors and create the netlist file, I get the appropriate connections on the PCB.

I very much appreciate the time you and Chris took to help a newbie. Now I don’t have to manually draw the tracks for these two voltage levels.


#11

Chris

Thank you very much for your help. Everything looks good on the PCB board and now I can use an auto-router that I just found from an Instructor on Udemy.com. Prior to this, I had to manually add the tracks for the power inputs.

Thanks again. Just an old retiree trying to learn something new!!


#12

The no pin to drive is from a missing “Power_Flag” symbol.
These are normally placed on both the GND nets and the power supply nets (So both 5V and 3V3.


#13

Paul

I just added the power flags and now I have a clean DRC. Thank you very much!