Selectable communication interface configurations for motion sensing devices. In one aspect, a module for a motion sensing device includes a motion processor connected to a device component and a first motion sensor, and a multiplexer having first and second positions. Only one of the multiplexer positions is selectable at a time, where the first position selectively couples the first motion sensor and the device component using a first bus, and the second position selectively couples the first motion sensor and the motion processor using a second bus, wherein communication of information over the second bus does not influence a communication bandwidth of the first bus.