* '''Vin''': This is the power pin into the Bluefruit module, it passes through a 3.3V regulator so this voltage can be from 3.3V to 16VDC and is reverse-polarity protected. If a battery is connected via the optional JST connector on the back, this pin becomes an output so you can power your microcontroller/project via the battery.<br />If you plan to use the optional JST connector on the back, don't provide power to this pin from the microcontroller | * '''Vin''': This is the power pin into the Bluefruit module, it passes through a 3.3V regulator so this voltage can be from 3.3V to 16VDC and is reverse-polarity protected. If a battery is connected via the optional JST connector on the back, this pin becomes an output so you can power your microcontroller/project via the battery.<br />If you plan to use the optional JST connector on the back, don't provide power to this pin from the microcontroller |