[HELP] GPIO signal during shutdown

[cyperghost]

Hello fellows,

According to the systemd helppage for system-halt we can initiate a script during shutoff sequence if we but a file to /lib/systemd/system-shutdown/ path. According to the halt signal we can choose between shutdowns, reboots .....

I'm able to use the file with full GPIO support on a PI0/1 and a PI2 ... So the LED blinks 3 times during shutdown. I'm not able to run this on a PI3 with RetroPie 4.3 and the STRETCH images also. So there seems no initiation of a GPIO during shutdown here.

So dear community I need your help. We need to connecte a LED to a working GPIO and to ground. then we need to create a small script and make it executable via chmod.

1. type sudo nano /lib/systemd/system-shutdown/gpio-shutoff
2. Insert code from box below!
3. Make script executable with sudo chmod +x /lib/systemd/system-shutdown/gpio-shutoff
4. Shutoff via commandline, ES menu or ....

example shutoff script!

#!/bin/sh	
# Testscript for proper GPIO signal on shutdown
	
led_pin=17	
		
    /bin/echo $led_pin > /sys/class/gpio/export	
    /bin/echo out > /sys/class/gpio/gpio$led_pin/direction	
	
        for iteration in 1 2 3; do	
            /bin/echo 0 > /sys/class/gpio/gpio$led_pin/value	
            /bin/sleep 0.2	
            /bin/echo 1 > /sys/class/gpio/gpio$led_pin/value	
            /bin/sleep 0.2	
       done	

/bin/sleep 5

So this script let's blink a LED connected to GPIO17 and GROUND

If you test can you please tell...
Which Raspberry did you use?
Which version of RetroPie or annother OS did you use?

Thank you
cyperghost

PS: @herb_fargus @BuZz any ideas? Link to starting thread

[cyperghost]

Tested: on Raspberry Pi 3 with RetroPie 4.3 and RetroPie 4.4 - works
Tested: on Raspbian STRECH 4.9 kernel (March 2018) - works

This is working flawless now!