The SH3003 can operate completely stand-alone, or under control of the microcontroller. A single-wire interface handles both bi-directional communications and the interrupt/wake-up signal from the SH3003. The SH3003 stores all configuration, calibration, parameters, and status information in a 36-byte bank of control registers. On reset, most of these are reloaded with defaults from the factory-set non-volatile memory. The microcontroller can change any settings on the fly. If some of the settings must remain fixed, a comprehensive set of write-protect bits is provided for several related groups of registers (with both permanent write-inhibit and lock/unlock capabilities).