[Fx30] n_reset (gpio6) interfering with IO3-OUT (gpio56)



I was planning to use the “n_reset” line (gpio 6) of the IoT internal connector to de-activate the IoT card during the initial manipulation of the IoT gpios. But, when I manually manipulate the level of the gpio6 I loose the control of the IO3-OUT line.


activates the IO3-OUT

echo 1 > /sys/class/gpio/gpio56/value

Here the IO3-OUT is clamped to the ground.

Take the control of the “n_reset” line

echo 6 > /sys/class/gpio/export

Here the IO3-OUT disconnects… (as well as the USER LED, maybe others as well…)

Doing “unexport” on the gpio 6 does not re-establish the control of the IO3-OUT.
From there the IO3-OUT control is lost till next reboot.

I am planning to build my own IoT card. I would really need to control the “n_reset” line to avoid transient states on the lines controlled by the IoT gpios.

Can you confirm this strange behaviour and tell me it there is a way around it, or if I should stop thinking about controlling the “n_reset” line?

Best regards, Christian.


Hi Christian,
I don’t recommend trying to control the nReset line. The signal is connected to the lan controller and the gpio expander. This is why you’re seeing the behaviour of the LED’s and the external IO.
Are you able to use one of the IOT gpio?