I would like to control the pin GPIODZ_15. I want to drive a microcontroller active-low reset pin, it has a 10k pull-up. It works fine with pin H4. Do I need to change a configuration file to desactive/activate something?

Thank you.


@SimonAmpleman GPIODZ_15 (pin 39 ) is a generic GPIO pin, all you need to do to use it is configure your program to communicate with it, instead of pin GPIOH_4, nothing special required for it :slightly_smiling_face:


echo 426 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio426/direction
echo 1 > /sys/class/gpio/gpio426/value
(pin doesn’t reflect logic high)

echo 431 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio431/direction
echo 1 > /sys/class/gpio/gpio431/value
(pin does reflect logic high)


Is that the correct pin number ?
I don’t recall if there was any dtb overlays required for it :face_with_raised_eyebrow:

update: pin 431 is a GND pin, refer to the docs

Yes I consulted the doc. I don’t understand why you say 431 is GND.
It clearly shows 431 as H4. and 426 as Z15.


sry, I mixed it up a little.
GPIODZ_15 is an input pin, so that is why its wasn’t giving the output


this is a bit confusing…

H4 also shows IN. But works fine with the output.

@SimonAmpleman I just remember this post from a while ago:

Yes, but it’s not PWM.

no, its not about PWM, the pin is an open drain
you need a pullup resistor it seems

Yes, as I explained in my original post, I have a 10k pull-up.

in that case, I suggest you consult with @Frank

@SimonAmpleman You can pull up or down the level of this pin ? If you can do it . it should can use to software pwm

There is also a demand on our project. Can you provide software pwm sample code?