I want to use a shutdown button to make a secure shutdown with the nanopi neo air. But i am completly lost how it works. I don't find out, which GPIO's i can use for a script.  And if i need a puuldown or not.

Can somebody help me?

 

Thanks 
Chris

I think i answer myself

 

I am to stupid to do it like i want, with python. But, shell scripts work everywhere an i understand it in most cases. So, here is an solution for my Problem.

 

I use PIN 18, which Linux GPIO is 201. I pot a pullup resistor (10kOhm) to PIN 17 - 3,3V.

After this, i configure the PIN18.

echo 201 > /sys/class/gpio/export
echo "in" > /sys/class/gpio/gpio201/direction

Now i can check the value

 

cat /sys/class/gpio/gpio201/value

The answer should be 1.

If now the PIN18 is shorted to PIN 20 (GND), the answer is 0.

A little script does it for me:

#!/bin/sh
BUTTON=201 # shutdown button

echo "$BUTTON" > /sys/class/gpio/export
echo "in" > /sys/class/gpio/gpio$BUTTON/direction

while true ; do
  data=`cat /sys/class/gpio/gpio$BUTTON/value`
  if [ "$data" -eq "0" ] ; then
    shutdown -h now
  else
    cnt=0
fi
  done