A switch sensor for sensing a state of a switch including a programmable memory, pulse generation circuitry, and comparator circuitry. The memory stores a state value indicative of a detected state of the switch. The pulse generation circuitry provides a pulse-train voltage signal to a first end of the switch, in which the pulse-train voltage signal is toggled between an active state for switch state detection and an inactive state for conserving power. A second terminal of the switch is coupled through resistive circuitry to a supply voltage node and may be coupled to an input terminal of the sensor. The comparator circuitry compares a state of the input terminal with the state value when the pulse-train voltage signal is in the active state for providing a state change signal indicative thereof.