A controller for a capacitive touch screen includes a touch resolve subsystem and a processor. The touch resolve subsystem, in response to a trigger input, measures a plurality of capacitance values using a plurality of input pins. The processor controls the touch resolve subsystem to acquire a baseline capacitance in a calibration mode, to acquire a frame comprising the plurality of capacitance values in a normal operation mode, and to update the baseline capacitance to a new baseline capacitance in the normal operation mode in response to the frame without entering the calibration mode.