Patent ID: 8345009

Claim:
An input device comprising: a matrix of keys forming a touch panel, each key corresponding to a different location of a touch screen and a different function or input data; a key controller to generate key touch status information of the key matrix including information of touched keys at least from a plurality of keys provided in the key matrix; and a controller to receive the key touch status information of the key matrix and controlling the key controller, wherein the controller is coupled to the key controller, wherein the key touch status information of the key matrix is transferred between the controller and the key controller through a serial communication link, wherein the key controller performs a key contact recognition operation to determine existence of a condition for at least one key in the matrix, said condition including at least one of a defective activation of the key or a weak-signal condition generated upon activation of the key in the matrix, and wherein the controller sends a forced reset signal to the key controller at predetermined intervals, the forced reset signal to initialize a communication status between the controller and key controller at said predetermined intervals.