Issue with setting GPIO pins as output.

RE: Issue with setting GPIO pins as output.

awneil — Fri, 26 Jul 2019 11:00:54 GMT

[quote userid="81560" url="~/f/nordic-q-a/50170/issue-with-setting-gpio-pins-as-output/200603"]the led doesn't work when connected to pin 16[/quote]

So that means the problem is not (just) down to your code - doesn't it?

There must be something else (also) wrong with your LED and/or the way you are connecting.

[quote userid="81560" url="~/f/nordic-q-a/50170/issue-with-setting-gpio-pins-as-output/200603"] I just used a wire to connect to an LED on a breadboard. [/quote]

You need to give more details!

preferably, a full schematic (aka "circuit diagram")

some good, clear, in-focus photos could also help.

[quote userid="81560" url="~/f/nordic-q-a/50170/issue-with-setting-gpio-pins-as-output/200603"] I am pretty new to embedded systems in general [/quote]

Do you have experience with basic electronics?

Here's some good beginner stuff on LEDs: https://electronicsclub.info/leds.htm

And some stuff on connecting LEDs to chips: https://electronicsclub.info/ics.htm

[quote userid="81560" url="~/f/nordic-q-a/50170/issue-with-setting-gpio-pins-as-output/200603"]is there a better way to test if the pin toggling is working[/quote]

As haakonsh says, an oscilloscope is the key tool.

You should be able to see that a pin is slowly toggling between high & low using a voltmeter - but a meter cannot show you if anything high-speed is happening.

RE: Issue with setting GPIO pins as output.

haakonsh — Fri, 26 Jul 2019 10:32:53 GMT

Yeah, an oscilloscope or digital analyzer.

Most likely you've not wired the LED circuit correctly.

RE: Issue with setting GPIO pins as output.

gojiman23 — Thu, 25 Jul 2019 17:52:23 GMT

No, the led doesn't work when connected to pin 16. I just used a wire to connect to an LED on a breadboard. I am pretty new to embedded systems in general so is there a better way to test if the pin toggling is working?

RE: Issue with setting GPIO pins as output.

awneil — Thu, 25 Jul 2019 17:42:02 GMT

So if you disconnect this "external LED" - is the pin toggling OK ?

If you connect this "external LED" - to pin 16, does it work?

RE: Issue with setting GPIO pins as output.

gojiman23 — Thu, 25 Jul 2019 16:57:05 GMT

Sorry, I meant an external LED*

RE: Issue with setting GPIO pins as output.

gojiman23 — Thu, 25 Jul 2019 16:24:50 GMT

Thanks, so I figured out that I am indeed using the right pin. If i switch the code to toggle Pin 16 then it works just fine on the board's LED, but for some reason an external LCD connected to pin 27 will not. Are there additional adjustments I have to make to my code for that or is it more likely to be a hardware issue?

RE: Issue with setting GPIO pins as output.

haakonsh — Thu, 25 Jul 2019 07:29:43 GMT

P0.27's location on the DK is described in the link in my last post. Your code is correct btw.

RE: Issue with setting GPIO pins as output.

gojiman23 — Wed, 24 Jul 2019 22:52:13 GMT

So how would I access p0.27 instead? Thank you for your help

RE: Issue with setting GPIO pins as output.

haakonsh — Wed, 24 Jul 2019 08:04:06 GMT

p0.27 is not the same as pin 27 on a given chip package.

Are you sure you're measuring the correct pin? See Connector interface for the position of p0.27

RE: Issue with setting GPIO pins as output.

gojiman23 — Tue, 23 Jul 2019 23:20:13 GMT

I'm using the nrf52840PDK. what is the difference between pin27 and P0.27?

RE: Issue with setting GPIO pins as output.

johnny — Tue, 23 Jul 2019 23:15:46 GMT

This look like correct

what is your hardware design?

maybe your pin use pin27 not P0.27