Power a Feather from a featherwing

[scobb00]

I'm porting a little Pi Zero Hat that had a 12V motor driver to the feather platform.
The hat had a 12V input used to drive the stepper motor. I also added a 5V regulator to take the 12V input and provide 5V to the Pi. This allowed me to just use a simple 12V PS to power the whole thing.

I'd like to have the same setup on my featherwing version. What isn't clear to me is the best way to power the feather from the 5V provided by my featherwing. Note: I'll never power from a battery.

Not trying to re-invent the wheel here. Is there a best or at least most common practice?

I think I see 4 possible options:
1) VBUS pin. Can I simply supply regulated 5V to that pin. Or, is it output only? Any concern if I have USB C plugged to laptop for development?
2) Use the battery input connector. Seems like a simple solution, but I worry that all of the battery charging circuitry would be in conflict.
3) USB C connector. I could wire the 5V from my regulator to a USB C cable. Is there any concern about ground planes that I should consider?
4) Using the VBAT pin. Same questions as 1) and 2)

Thanks,
Steve

[adafruit_support_bill]

#3 is the best option since you will need to pull the plug before connecting to USB. Powering via VBus risks conflicting 5v regulators when also connected via USB. Powering via VBat or the JST connector puts the battery charge controller into 'undefined' territory when also powered via USB.

[scobb00]

Thanks for the reply - yes, that does seem to be the cleanest solution. Also, there is no need for hot swapping - you are either "debugging" - or "using" the device.

Question regarding debugging... I will have the 12V hooked up always as it is used to driver the motor via the motor driver module. Under normal use, (5V comes from the 12V) the signal ground and the 12V ground can be the same / tied together. Do I need to separate the grounds if I'm getting 5V from the USB connector to the PC? The motor driver allows for that (2 separate gnd pins).

Thanks

[adafruit_support_bill]

In most cases where you have multiple power sources powering connected circuitry, you want to tie all grounds together so that you have a common ground reference. In the case of the Motor Wing, the ground from the motor power terminals is already connected to the ground-plane of the Wing - and therefore to the ground-plane of the Feather as well.

[scobb00]

OK - great. That is easier. Keeping the ground planes the same should make it easier to lay out as well.

Appreciate your help.

Steve