Project

General

Profile

Download (733 Bytes)

Can't read state of output GPIO pins » gpio_read_output_test.sh

bash script demonstrating the issue - Tim Troester, 03/16/2026 05:43 PM

 
export GPIO_PIN_NUMBER=638 # corresponds to /dev/gpiochip2, line index 10

echo $GPIO_PIN_NUMBER > /sys/class/gpio/export

trap "echo $GPIO_PIN_NUMBER > /sys/class/gpio/unexport" EXIT

echo "EXPORTED PIN ${GPIO_PIN_NUMBER}: "
ls /sys/class/gpio

echo "SETTING MODE TO OUTPUT"
echo 'out' > /sys/class/gpio/gpio${GPIO_PIN_NUMBER}/direction

while true; do
echo "SETTING VALUE TO 1"
echo 1 > /sys/class/gpio/gpio${GPIO_PIN_NUMBER}/value
echo "VALUE IS: " $(cat /sys/class/gpio/gpio${GPIO_PIN_NUMBER}/value)
sleep 5

echo "SETTING VALUE TO 0"
echo 0 > /sys/class/gpio/gpio${GPIO_PIN_NUMBER}/value
echo "VALUE IS: " $(cat /sys/class/gpio/gpio${GPIO_PIN_NUMBER}/value)
sleep 5
done
(2-2/2)
Go to top