Raspberry Pi gpio output doesn't work

Question

I am trying to create a simple blinking led application using Pi 3 model A+.

After some experiments it turns out that for some reason I not able to bring any gpio pin to High state.

I have tried both C, Python and gpio script to turn pin to High, but it doesn't work. I have tested both with the led and with "gpio readall", but all output are always 0.

What I did managed to change is to change the mode of the pins from Input to Output. It always worked without any problem.

Any idea what can be a reason for the problems with outputs? I just started experimenting with gpio, so I don't think I could burn it already and I did only resistance + led tests. Also constant 3v and 5v pins work properly, so I still hope that it gpio is functional.

Any ideas are very welcome,

Thanks

shabaz · Answer

Hi Lev,

There's not enough information to be sure (and a photo and code can help!), but if I had to guess, if you think the code is fine, then there's a chance it could be one of these things:

* Incorrect pin is being connected to the LED (the GPIO numbering doesn't map 1:1 with the physical connector numbering)

* If you're using jumper wires there's a possibility the wire could be faulty (some have been known to have the conductor cut and just hanging on by the plastic insulation being crimped).

* Incorrect orientation of the LED (can be tested first by trying to connect it to the 3.3V output on the connector, via a resistor).

There's a photo how to connect an LED and test the output, here:

Raspberry Pi GPIO Explained