UNO V3 can get power via USB, barrel jack, or the Vin pin. Is it safe to have USB plugged in while 6v is supplied from battery via the barrel jack?
It's fine. I've got a project where I need higher voltage for something else so I power it from the barrel jack (12V). When I was testing & updating software I had the USB plugged in at the same time.
With 6V there will be some voltage loss across the voltage regulator and the USB MIGHT end-up supplying the power/current.
Thank you. Safety is my main concern. I didn't know if the circuitry can handle conflicting power inputs. It's a portable three axis joystick controller on battery power that sometimes needs software updates.
It's safe but useless. The barrel jack, and Vin, need 7.5 volt, up to 12 volt to work.
Thanks. I'll add a couple more AAA cells.