A method and an apparatus for operating an electronic sensor and an electronic user input are provided. In one configuration, the apparatus includes a detection circuit configured to recognize a user input voltage generated by an electronic user input and a power supply configured to supply power to a detection circuit continuous without polling. In another configuration, the apparatus includes a port, a first power supply, a second power supply, and a control circuit configured to selectively couple the first power supply or the second power supply to the port based on a state of operation of an electronic sensor coupled to the port.