A touch screen controller is for a drive line emitting a periodic signal and capacitively intersecting sense lines. A selection circuit, for each of a number of portions of the periodic signal equal to a number of the sense lines, couples a first subset of the sense lines to a first output path, and couples a second subset of the sense lines to a second output path, the second subset being sense lines not included in the first subset. Processing circuitry, for each portion of the periodic signal, measures a capacitance of the first output path, measures a capacitance of the second output path, and sums the capacitance of the first output path and the capacitance of the second output path. The processing circuitry determines a capacitance between each sense line of the first and second subsets and the drive line as a function of the sums.