I have a question about gpio testing environment.
I want to check gpio value so I connected between PIN #31 (sysfs 200) and PIN #34 (GND) directly in Jetson Nano. I attached cable connection picture.
And I run below command.
echo 200 > /sys/class/gpio/export
I want to check that changing value, but the value is always 0.
How can I check GPIO value changing? I want to check GPIO pin is worked in software.
You need to set direction and you can change the output value.
sudo echo 200 > /sys/class/gpio/export
sudo echo out > /sys/class/gpio/gpio200/direction
sudo echo 1 > /sys/class/gpio/gpio200/value
I think I wrote question unclearly.
What I intended test case :
If PIN #31 (GPIO) and PIN #34 (GND) are connecting, PIN #31 value will be 0.
If PIN #31 (GPIO) and PIN #1 (3.3 VDC) are connecting, PIN #31 value will be 1.
So, I think GPIO direction should be “in”.
But, the two cases’ value are 0. I think it is not worked.
I want to see that the value is changing.
What do you see when you typing below command ?
sudo cat /sys/class/gpio/gpio200/direction
Is this still an issue to support?
It solved. I think that if GPIO direction is not changing after booting, it should be “in” status, but it needs to setting direction explicity.
After run “echo in > /sys/class/gpio/gpio200/direction”, when I changing PIN connection, I checked GPIO value has changed.
Thanks for support.