Feather M4 CAN with external 5V supply

[alecpr]

I'm looking to use the Feather M4 CAN Express to control an ODrive Pro motor driver. I'd like to power the Feather from the ODrive (not the USB, not the LiPo battery) which offers 5V or 3.3V power outputs.

Can I supply 5V to VBATT via the JST connector? I see VBATT recommended input is 3.7-4.2V (based on the LiPo battery) but I don't see a MAX/MIN.

Alternatively, I saw reference to connecting 3.3V power directly to the Feather 3.3V pin (3V in the pinout diagram). This is an option, but using the JST connector input would be easier.

[T_Mo]

(Community member)
I think it's recommended to provide 5V to either of the VBUS signals - via the USB connector, or the VBUS pin #3 on the shorter Feather connector.

I don't recommend applying 3.3 volts to the 3.3V pin or the VBAT pin. One is the voltage regulator output, the other is the LiPo charger output. Driving those pins externally could make some funky things happen.

[alecpr]

Thanks! To confirm, are you recommending to connect external power +5V (to VBUS) and GND to the pins circled in pink?

power_pins.jpg (119.24 KiB) Viewed 24 times

[T_Mo]

Yes.

[adafruit_support_carter]

Yep, don't use VBAT.

More info here:
https://learn.adafruit.com/adafruit-fea ... management

Keep in mind that the VBUS pin is directly tied to USB power. So it's technically more of an output than a power input. So you'll want to be careful to not connect external power and USB at the same time.
https://learn.adafruit.com/adafruit-fea ... er-3078974