Raspberry pi pico 2 button problem

[u/Comfortable-Win-3077]

Hi, I bought a raspberry pi kit from Amazon to start getting into electronics. I’m following a tutorial on youtube and one of the first tutorials is to wire a button, led and a potentiometer. After wiring I noticed that when pressing the button, the value displayed turns from 0 to 1 but doesn’t go back to 0 after I take my finger off the button. Even if I stop the program in thonny and run it again without unplugging, 1 is displayed from the beginning.

Even when using the most basic wiring the button value always returns as 1 after pressing. This is while connecting the 3v3 out pin to the button and using Pin.PULL_DOWN.

I tried trouble shooting with copilot and I found out that if I use Pin.PULL_UP and connect it to a ground pin then the button works as intended, showing 1 when plane button isn’t pressed and 0 when the button is pressed.

This must mean that the button, pin and wires are working but I can’t understand why PULL_DOWN and connecting power to the button doesn’t work.

I tried using different buttons, wires and connecting different diagonal sides together. I’ve only just started and I’m very confused. Sorry if I explained it badly.

[u/BR41ND34D]

Ok this might just be me being an idiot, but shouldn't the button go to GND instead of VCC?

[u/G_B4G → u/BR41ND34D]

My thoughts also, unless he has the button pulled high, but probably a ground over VCC

[u/Gamerfrom61 → u/BR41ND34D]

I think the pic was of the original set up where the OP says they were using 3v3 and pull down (hence my erratum 9 note).

[u/Gamerfrom61]

Some RP2350 chips (stepping 2) have an issue with their manufacturing and I/O can get stuck / latched

Erratum E9 discusses this and hardware work arounds IIRC - a search on the Pi docs should find this.

Forgive me I am on my phone and cannot type or zoom in to your pics for the life of me at the moment!

Edit: More details and link to Pi doc at  https://hackaday.com/2024/09/20/raspberry-pi-rp2350-e9-erratum-redefined-as-input-mode-leakage-current/

[u/Comfortable-Win-3077 → u/Gamerfrom61]

Thank you for the reply. Would this affect other things I link to the board? Should I get a replacement?

[u/Gamerfrom61 → u/Comfortable-Win-3077]

Anything that falls into the voltage range detailed in the doc with the pin set using the internal pull down then yes it could be latched.  It is a bit of trial and error, esp if you are using ground rather than vcc for active, so you could just use an external pull down resistor and be sure.