LE_poweroff.sh

#!/bin/bash

#This is GPIO 3 ( 5 in diagram).
#This is an input from ATXRaspi to the Pi.
#When button is held for ~3 seconds, this pin will become LOW signalling to this script to poweroff the Pi.
SHUTDOWN=3
REBOOTPULSEMINIMUM=50     #reboot pulse signal should be at least this long
REBOOTPULSEMAXIMUM=1000      #reboot pulse signal should be at most this long
echo "$SHUTDOWN" > /sys/class/gpio/export
echo "in" > /sys/class/gpio/gpio$SHUTDOWN/direction

#Added reboot feature (with ATXRaspi R2.6 (or ATXRaspi 2.5 with blue dot on chip)
#Hold ATXRaspi button for at least 500ms but no more than 2000ms and a reboot HIGH pulse of 500ms length will be issued

#This is GPIO 14 (8 in diagram).
#This is an output from Pi to ATXRaspi and signals that the Pi has booted.
#This pin is asserted HIGH as soon as this script runs (by writing "1" to /sys/class/gpio/gpio14/value)
BOOT=14
echo "$BOOT" > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio$BOOT/direction
echo "1" > /sys/class/gpio/gpio$BOOT/value

echo "ATXRaspi shutdown script started: asserted pins 
($SHUTDOWN=input,HIGH; $BOOT=output,HIGH). Waiting for GPIO$SHUTDOWN 
to become LOW..."

#This loop continuously checks if the shutdown button was pressed on ATXRaspi (GPIO7 to become LOW), and issues a shutdown when that happens.
#It sleeps as long as that has not happened.
while [ 1 ]; do
  shutdownSignal=$(cat /sys/class/gpio/gpio$SHUTDOWN/value)
  if [ $shutdownSignal = 1 ]; then
    /bin/sleep 0.2
  else  
    pulseStart=$(date +%s%N | cut -b1-13)
 # mark the time when Shutoff signal went HIGH (milliseconds since epoch)
    while [ $shutdownSignal = 0 ]; do
      /bin/sleep 0.02
      if [ $(($(date +%s%N | cut -b1-13)-$pulseStart)) -gt $REBOOTPULSEMAXIMUM ]; then
        echo "ATXRaspi triggered a shutdown signal, halting Rpi ... "
        poweroff
        exit
      fi
      shutdownSignal=$(cat /sys/class/gpio/gpio$SHUTDOWN/value)
    done
    #pulse went LOW, check if it was long enough, and trigger reboot
    if [ $(($(date +%s%N | cut -b1-13)-$pulseStart)) -gt $REBOOTPULSEMINIMUM ]; then 
      echo "ATXRaspi triggered a reboot signal, recycling Rpi ... "
      reboot
      exit
    fi
  fi
done