Need to use serial to connect pc to Pi about lipopi HOT 6 CLOSED

@karlahaiat See "A Simple Press (no hold) Power Up Version" here: Power-up/power down

from lipopi.

The GPIO 14 (UART TXD) is the only pin which goes high at power on and low at power off. If you check the issues, others have used different pins but they have to write a script to make the GPIO high and hold the power button down until the Pi is booted.

from lipopi.

There are a number of pins that boot to HIGH. e.g. for rpi0 BCM2835 Arm Peripherals 6.2 Alternative function assignments indicates the pins that go high at power on are:
* GPIO/BCM: 0, 1, 2, 3, 4, 5, 6, 7, 8, 34, 35, 36

So these pins should be able to be substituted for UART. Obviously some of these pins have other functions that you may not want to interfere with so it's up to you to pick which one works.
I'm not sure if this is the same for other rpi's - you will have to check the documentation.

I am using pin 5 at the moment and I don't have to hold the power button down for it to start up.

But there is another change necessary to ensure that the pin goes low on power down, here I used the power-off dtoverlay.
bash $ sudo nano /boot/config.txt`
Add the following line:
dtoverlay=gpio-poweroff,gpiopin=5,active_low="y"
Replace "5" with whichever power_disable_pin you are using.

This worked for me - hope it helps.

from lipopi.

There are other pins which boot to high but they don't go high straight away and stay high until the end of shutdown as far as I know?

from lipopi.

I should have mentioned this is using the RC power up/power down circuit. The RC response gives enough time for the pin to go high. The dtoverlay ensures the pin goes low to disable power at the end of shutdown.
People have used scopes to examine this behaviour here: https://www.raspberrypi.org/forums/viewtopic.php?t=201483

from lipopi.

from lipopi.