New answers tagged power
0
I have had both of these work to force pin 17 low after shutdown. Not sure if this will work for your situation or with any other pins.
option 1.
edit /boot/config.txt
add this
dtoverlay=gpio-poweroff,gpiopin=17,active_low=1
option 2
run this from command line
sudo dtoverlay -v gpio-poweroff gpiopin=17 active_low=1
1
The Pi 3 is protected by the SMBJ5.0A over-voltage suppressor, which has a breakdown voltage between 6.4 and 7.1V. So above 7.1V you are guaranteed to trigger the over-voltage protection.
If the protection works as designed, you'll see no smoke: the polyfuse will limit the current to a safe value. However, 7.1V is above the rated maximum voltage of 5V ...
1
The Pi is rated at 5.0 ± 0.25V.
The PMIC (on modern Pi) has a MAXIMUM input of 5.5V - exceed this at your peril.
The "protection" circuitry consists of a combination of polyfuse, ideal diode and surge limiting diode, which varies on model (consult schematics for detail). The Pi3A+ has no ideal diode.
Schematics for most models are available.
See ...
2
With a 1kΩ resistor you can't pull the pin LOW. You will get ~1.2V which is HIGH.
Just get rid of it or reduce to 100Ω.
There is no need for a resistor; it is a protection mechanism to prevent excessive current for an unlikely combination of circumstances.
An opto-isolator would never be capable of pulling enough current to cause problems.
2
The pijuice library GetStatus() function should give you what you need:
https://github.com/PiSupply/PiJuice/blob/master/Software/README.md#pijuice-status
GetStatus()
Gets basic PiJuice status information about power inputs, battery and events.
Returns:
{'data':{
'isFault':is_fault,
'isButton':is_button,
'battery':battery_status,
'powerInput':...
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