[RPi3b+] bootup GPIO set to high

alexamend · January 16, 2019 at 7:11 PM

Hi I am new here,

Currently I used several Rpi on which Libreelec is running. Currently I am building a radio based on Libreelec, now I am looking for a way to set one of the GPIO already high when turning it on so that I can realize a self-holding of a button. In the further program run this button should react on a second GPIO and shut down the system again. I'm grateful for every approach. kindly Alex

**HiassofT** · January 16, 2019 at 7:23 PM

Have a look at the gpio-shutdown dtoverlay https://github.com/raspberrypi/linux/blob/rpi-4.19.y/arch/arm/boot/dts/overlays/readme#l692-l721

By shorting pin5 and pin6 on the GPIO header you can shutdown LibreELEC and if you then press the button again it'll power up again.

so long,

Hias

alexamend · January 16, 2019 at 7:47 PM

Hi Hias,

Thanks for Information,

I know that with P5/P6 unfortunately this does not work in my case, I want to turn off the RPi completely but P5/P6 needed the RPi in standby. But I always want to turn off the RPi completely because it has the 7 "touch display and the back light lights up in the standby.

Also, the connected amplifier should not run in standby.

Alex

**HiassofT** · January 16, 2019 at 7:53 PM

Without external hardware you can't turn off the RPi completely. You can use eg the gpio-poweroff overlay to signal shutdown to an external circuit which then cuts power to the RPi.

so long,

Hias

alexamend · January 16, 2019 at 8:25 PM

Hi Hias,

I have allready external hardware to completely turn off. Now i surch for solution to get one GPIO set to high during power on.

Alex

**Da Flex** · January 16, 2019 at 8:37 PM Official Post

Quote from alexamend

Now i search for solution to get one GPIO set to high during power on.

That's pretty easy, if you call a Python script from the autostart script. I did that to activate a status LED when LE starts - look here.

**HiassofT** · January 16, 2019 at 8:48 PM

Use pin5 - it has an external pull-up on the board so it's guaranteed to be high as soon as power is applied.

You can also use the gpio-shutdown overlay with other GPIO pins to get a shutdown button if you don't want to use pin 5 for that.

Powerup from shutdown by shorting pin 5 to GND is independent of overlays, that's a feature of the RPi (GPU) firmware which will always work.

so long,

Hias

alexamend · January 17, 2019 at 7:55 AM

Here is my first version of a standalone radio based on raspian, all running on a "RPi Rev.2"

I had written the radio program in C at that time.

There was still the possibility to access the GPIO=00 which is no longer possible with the RPi3b+ version,

at that time I had to unsolder the pull up resistances as they caused problems.

I will try with the P5, - "I'll let you know if it works"

I had not thought of that until now, because I still miss the full schematic of the RPi3b+, I only foud the reduced schematic

In the attachment you see the wiring diagram of my first version of the radio

SORRY that the wiring diagram is in German in some places.

In the lower left side you can see the on/off switch to the right of it is the self-holding which is supplied with the GPIO=00.

Alex