A capacitive touch sensor circuitry comprises an interface for interconnecting with a plurality of I/O pins that connect to rows and columns of a capacitive sensor array. Monitoring circuitry, responsive to inputs from the plurality of I/O pins, determines when a capacitive switch in the capacitive sensor array has been actuated and stores an indication of the actuation of the capacitive switch. The monitoring circuitry then generates an interrupt responsive to the determined actuation. A control engine controls a manner in which the monitoring circuitry monitors the plurality of I/O pins. The control engine and the monitoring circuitry may be configured to monitor the plurality of I/O pins in a plurality of operating modes.