A processor module includes memory having instructions for executing functions of a handheld diabetes management device and a processor that selectively executes the instructions. Battery terminals electrically connect the processor module with a re-chargeable battery. A receptacle is configured in accordance with a universal serial bus (USB) standard. A component is included for communicating information from the handheld diabetes management device to a user or another device. A multiplexer module relays power from the receptacle to a bus voltage node. A first switching device is connected between the bus voltage node and a second voltage node. The component receives power from the second voltage node. A second switching device is connected between the bus voltage node and a third voltage node. The processor module is directly connected to the bus voltage node and to the third voltage node.