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What happens to the GPIO when the Pi is shut down?
Even when the Pi is shutdown the Video Core continues to run, and the GPIO pins retain their state; only the CPU is not running. The 3.3V is supplied by separate circuitry and will be present while ever the Pi is connected to a 5V supply.
Where is the shutdown button on a Raspberry Pi?
Just make sure it’s normally open (push to close). Connect the button between GPIO 27 and GND. If you use an ATX power button and a Raspberry Pi with a 40-pin GPIO header, connect it across the seventh column from the left: This shorts GPIO 27 (physical pin 13) to ground (physical pin 14) when the button is pressed.
What happens when you press Ctrl + C on a GPIO?
So when you press CTRL+C, it prints the current value of counter, cleans up any GPIO ports you’ve used, and exits. The code in the except: block (lines 20-24) covers all other exceptions – including program errors. So if another exeption occurs, it warns you, cleans up any GPIO ports you’ve used, and exits.
How to exit an RPi.gpio program cleanly?
If you want to try it out, it’s a bit long for a live Python session, so you could retype it, or cut and paste it into a program as we did in the first post in this series Now you know how to exit an RPi.GPIO program cleanly, without leaving a trail of uncontrolled ports behind you.
Why does Raspberry Pi not turn off GPIO?
With U-Boot the Raspberry Pi boots and works normally, it even shuts down but it never toggles GPIO6. This leaves the PSU running and the only way to fix it is by holding down the power button for at least 5 seconds.
How does GPIO-poweroff work on RPI 4?
Use of this overlay (and the gpio-poweroff mechanism) required that there is an external mechanism to remove the power in response to the GPIO being toggled. Failure to do so within the allowed window (3 seconds is the default) results in a kernel warning, followed by undefined behaviour.
What causes kernel panic when GPIO is shutdown?
Adding the gpio-poweroff device tree overlay to the /boot/config.txt file results in a kernel panic when the Pi is shutdown using ‘sudo shutdown -h 0’. I have added the following 2 lines to the /boot/config.txt file:-