Apparatus and method for waking up a processor

A method comprising:

• while a first processor and a second processor are in a continuous sleep state, receiving an event;
• responsive to the event, interrupting the second processor, causing the second processor to enter an active state;
• receiving a trace input via a touch screen, the touch screen being operatively coupled with the second processor while the first processor is in an inactive state;
• determining by the second processor, whether the trace input corresponds to data including a signature pattern in relation to an user touch input transmitted from the first processor to the second processor while the first processor was in an active state;
• and
• sending a signal from the second processor to the first processor to transition the first processor from the sleep state to the active state based at least in part on a determination that the trace input corresponds to the data
• wherein the event comprises removal of a stylus from a holder,
• wherein causing the second processor to enter an active state further comprises causing the second processor to enter the active state for at least a predetermined period of time, responsive to removal of the stylus from the holder;
• the method further comprising:
• returning the second processor to the continuous sleep state when during the predetermined period of time, the second processor does not determine that the trace input corresponds to data including a signature pattern.