Pin connected to some others pins but no pin to drive it [for VSS and VDD]

I have been stuck here for an hour and have already checked if there are any broken wires but there are not… I have also viewed the info abt the said type of error but it seems to not apply to mine. What do you guys think is the problem?

(Start Here) Frequently Asked Questions

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May I know how to open the pin properties? Thank you.

This is one of the most asked questions.

And it has it’s own entry in the FAQ section:

What do you mean with “pin properties” (and where)?
The most generic answer is to first load a schematic symbol in the symbol editor, then hover over a pin and press e for edit.
But you have to be aware that KiCad’s own libraries are read-only so you can not copy them directly and have to learn to do some library management first.

Looks like you need to add PWR_FLAG to your VDD and VSS.


As well as Pwr_Flags, from a practical perspective, where is the +5v / 0v magically coming from? It needs a connector of some sort. And some decoupling capacitors & a smoothing capacitor.


I wanted to mention this, but it slipped my mind by the time I had written the rest of my previous post.

You also need to add some kind of current limiting for the LED’s, unless you want to rely on the 4017 to limit LED current, which is “dubious”. But with the way your LED’s are placed they are also blocking the current.
It probably works better if you turn all the LED’s 180 degrees, and then connect a resistor between GND and the common cathodes of your LED’s.


I hadn’t picked up on the LEDs. The practice of having LEDs to +5v (via a resistor normally) goes back to TTL days, where TTL has a much better ability to sink current when low, compared to sourcing current when high.

If you look at the 4017 data sheet, typically of CMOS, the device can sink about 1mA, and can source 2 to 3mA, both a bit low, so you’d get a pretty dim LED. To be honest, 4000 series is NOT designed for driving LEDs! The 74HC4017 device might be a better choice, with a max output current of +/- 25mA (series resistor essential in that case!!!)

Long time ago to make red LED lighting good I used about 20mA. Nowadays I drive red LEDs with 2mA. Few years ago I found new green LEDs with higher voltage drop than previously. It turned out that in order not to shine too brightly, you need to give them less than 1mA.

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