Power pins during CM3 power off

balenaFin
1

Hi,

For my project, I’d like to know which pins on the Fin are powered and which aren’t when the Pi is switched off by the coprocessor. I couldn’t find a list of these anywhere, but from the datasheet and schematics I think that the following is true:

  • EXP 3V3 is powered
  • HAT 5V is powered
  • HAT 3V3 is NOT powered
  • mPCIe is NOT powered
  • USB is NOT powered (both the header and the ports)

Can anyone confirm?

Regards,
Marten

2

Hi Marten,
Let me get in touch with our FIN engineers to confirm this 100%, but from my point of view your list looks good.
Kind regards,
Theodor

5

Hi @martenjacobs that is correct:

  • Only the the 5V pins (pins 2 and 4) on the compute module header (HAT) are powered
  • All the pins on the coprocessor header are powered
  • mPCIe and USB are not powered.

Cheers,
Nico

7

OK, so that would mean the 5V HAT pins are not powered either? From what I see in the schematics the 5V is powered directly from U27, so I’d say they would stay powered. Or am I missing something?

9

@martenjacobs, sorry for the confusion, the 5V in the HAT header is powered. I edited my previous message.