Abstract: Certain aspects relate to systems and techniques for scan control for scanning a touch panel. The scan control system can alternate adaptively between scanning the touch panel in a passive scan mode requiring minimal power and in a focused active scan mode that sequentially scans only a portion of the touch panel. The scan control system can monitor the absolute capacitance of some or all of the sensors of the touch panel in passive scan mode and can monitor the mutual capacitance of a portion of the touch panel in focused active scan mode. If the absolute capacitance of any sensor is greater than the baseline capacitance, then the scan control can use this absolute capacitance touch data to determine one or more sub-regions of the touch panel for scanning in focused active scan mode. The mutual capacitance touch data can be used for determining features of the touch event.

Abstract: Certain aspects relate to systems and techniques for scan control for scanning a touch panel. The scan control system can alternate adaptively between scanning the touch panel in a passive scan mode requiring minimal power and in a focused active scan mode that sequentially scans only a portion of the touch panel. The scan control system can monitor the absolute capacitance of some or all of the sensors of the touch panel in passive scan mode and can monitor the mutual capacitance of a portion of the touch panel in focused active scan mode. If the absolute capacitance of any sensor is greater than the baseline capacitance, then the scan control can use this absolute capacitance touch data to determine one or more sub-regions of the touch panel for scanning in focused active scan mode. The mutual capacitance touch data can be used for determining features of the touch event.

Abstract: Described herein are methods and devices that employ a predefined class of anchor-drag touches to minimize host processor use in a mobile computing device. As described, detecting anchor-drag touch gestures enables the touch screen controller to handle a large portion of touch processing, even in mobile devices with larger displays. A first touch establishes an anchor area, from which a drag area is calculated, and a second touch within the drag area provides a command to the device. Some embodiments may limit subsequent touch processing to the identified drag area.