Abstract: An event driven wake-up system for controlling current consumption by a microcontroller that controls a data input device used to enter data to a data processing system is provided. The wake-up system include a data input device, such as a keyboard, that is responsive to an external event, such as depression of a key on the keyboard, by providing a signal indicative of the occurrence of the external event. The microcontroller responds to the external event by generating a data character that corresponds to the signal received from the data input device and provides that data character to the CPU of the data processing system. The microcontroller includes means for sensing inactivity at the data input device and for entering the microcontroller into a reduce current consumption mode when such inactivity is sensed.