MightyHat Power output with Pine64 [SOLVED]

[BenCranston]

I installed a 1000uF 10v cap, un-bridged the *always on* header and, welp..  my MH is fried.  Without load (disconnected from the Pi) it behaves correctly.  Connect it to the Pi header and *nothing* starts on the MH.  The display, the moteino nothing.  guess I truly did fry a component or two. 

[Felix]

Ok if you'd like to return it I can take a look and try to repair it?
PM me for the return details.

[phill]

Hmm, I don't quite understand. Doesn't the pine support a backup battery by default? What then are you using the MightyHat for?

[Felix]

I talked to Ben in private and he found there is some sort of bug or known issue with the Pine64 where it would not allow the 5V rail to be fed through the header, thus causing a conflict with the MightyHat. He was able to resolve that but I don't know the details, I am hoping Ben can fill in the details here.

[BenCranston]

Yes indeed, the Pine64 is NOT *really* compatible on it's Pi2 header.  I've discovered several things since talking with Felix about it.  First the Pi2 interface does not accept input power.  There's a thread over on the Pine64 forum with some of the details:  http://forum.pine64.org/showthread.php?tid=1363&pid=23360#pid23360

So I re-routed the 5v output from the MH over to the Euler bus DC In pins and the power switching works fine now.  I ended up cutting the 5V header pins between the MH and the Pine64.

I also discovered another *incompatibility* between the Pine and a RPi.  The GPIO reset pin from the Pine is in the opposite logic state as compared to the RPi before power up, so the Moteino is stuck in reset.  So I opened that jumper to allow the Moteino to boot and begin power supervision.

At this point I have a workable implementation on my non-standard board.

[Felix]

Ben - thanks very much for clarifying!