Picade HAT shutdown cicuit does not shutdown Pi Zero W


#1

I’m building an audio player with the picade HAT.
While the shutdown mechanism is working flawlessly on a Pi 2 B, what it does on my Pi Zero W is to shut it down, and after a brief second the activity LED is lighting up again and the Pi boots back up.
So it looks to me as if something with the shutdown circuit logic does not work right on the Zero W.
(I already flashed the latest firmware and tested different power supplies; plugged into the picade of course)

Please note this is the same Zero W that has a non functional WIFI (my previous post). Maybe it’s completely flawed…


#2

Usually this means something is erroneously asserting the shutdown pin, although I’m not sure what it could be. For sanitys sake

  1. Make sure you’re powering the setup through the HAT
  2. Make sure 1-Wire is not enabled in raspi-config

#3

Thank you for your suggestions, but unfortunately I had no success.

Furthermore I noticed that the Pi also won’t stop by “sudo poweroff” - as long as the picade HAT is connected, it will reboot immediately. Even tested with a fresh card image of raspian.

Can you tell if the HAT has been tested with the Pi Zero W, the power circuit in particular?
I can only try to get another Zero W and retest, but I don’t have one right now.


#4

Hi!

We haven’t found any problems with the power switch with Zero W in our testing. Have you got anything else plugged to the Pi that might have added capacitance to the 3V3 power line? In theory a non-functional wifi chip might also cause that, by not emptying the 3.3V capacitors onboard the Pi quickly enough at shutdown. You could try to add a 1k ohm resistor* between the Pi’s 3.3V and ground pins and see if that helps.

  • If you don’t have a 1k ohm resistor handy, anything between 1k and 10k ohm should work.

#5

Hey!

Consider me impressed :) I connected a 1.5 kOhm resistor to the exposed 3.3V and GND pins of the HAT. This did the trick! Many thanks!