I have a hardware question to submit to the community. I want to power the Spark Core from a car battery so I’m using an external step-down regulator with a range up to 30V.
When I connect the Core through USB to debug using Serial, I am wary of connecting together the outputs of the 2 voltage regulators (external 12V to 3.3V and internal VUSB 5V to 3.3V). I removed D1 (the diode from VUSB to the input of the internal regulator), soldered a wire from the VUSB pad to an external diode then to the input of of external regulator.
Do you agree with my caution or do you think nothing bad will happen if both regulators are connected together? Is there an easier way of doing this?