1. A method for determining an object sensing mode of a touch sensor panel, comprising: at an electronic device with one or more processors and memory, operating the touch sensor panel in a first object sensing mode having a first resolution in which each of a first plurality of sensing electrodes are individually measured and thereafter measurement signals from respective sensing electrodes of the first plurality of sensing electrodes are averaged to determine a presence of an object, if a first touch or proximity event is detected in the first object sensing mode, switching the touch sensor panel to operate in a second object sensing mode having a second resolution in which each of a second plurality of sensing electrodes are individually measured to determine the presence and a location of the object, and if no second touch or proximity event is detected in the second object sensing mode, switching the touch sensor panel back to operate in the first object sensing mode.