Method and Apparatus for Interfacing with a Touch Sensor

A method of interfacing with a touch sensor having a grid of column lines and row lines for sensing touch inputs to a touch surface of the touch sensor, the method comprising:

• reading the touch sensor by exciting one or more column lines and row lines with one or more excitation frequencies to produce sensing signals that are frequency-domain transformed, and evaluating transform values corresponding to the one or more excitation frequencies, and wherein the reading is performed hierarchically by:
• reading the touch sensor at a first resolution that is less than a full resolution, based on logically subdividing all or a targeted zone of the touch surface into multiple first regions and applying excitation frequencies on a per first region basis, each first region involving multiple column lines or row lines;
• and
• responsive to detecting a touch input in a particular one of the first regions, performing one or more further readings of the touch sensor to discriminate a touch location of the touch input at the full resolution, each further reading based on further subdividing the particular first region by allocating one or more additional excitation frequencies for column or row excitation within the particular first region.

An apparatus configured for interfacing with a touch sensor having a grid of column lines and row lines for sensing touch inputs to a touch surface of the touch sensor, the apparatus comprising:

• reading circuitry;
• and
• processing circuitry operative to read the touch sensor via the reading circuitry, based on exciting one or more column lines and row lines with one or more excitation frequencies to produce sensing signals that are frequency-domain transformed, and evaluating transform values corresponding to the one or more excitation frequencies, and wherein the reading is performed hierarchically based on the processing circuitry being configured to:
• read the touch sensor at a first resolution that is less than a full resolution, based on logically subdividing all or a targeted zone of the touch surface into multiple first regions and applying excitation frequencies on a per first region basis, each first region involving multiple column lines or row lines;
• and
• responsive to detecting a touch input in a particular one of the first regions, perform one or more further readings of the touch sensor to discriminate a touch location of the touch input at the full resolution, each further reading based on further subdividing the particular first region by allocating one or more additional excitation frequencies for column or row excitation within the particular first region.

An electronic device, the electronic device comprising:

• a touch sensor having a grid of column lines and row lines for sensing touch inputs to a touch surface of the touch sensor;
• host processing circuitry configured for execution of one or more software applications that use the touch sensor as a control input;
• and
• an apparatus configured to interface the host processing circuitry with the touch sensor, the apparatus comprising:
• reading circuitry;
• and
• processing circuitry operative to read the touch sensor via the reading circuitry, based on exciting one or more column lines and row lines with one or more excitation frequencies to produce sensing signals that are frequency-domain transformed, and evaluating transform values corresponding to the one or more excitation frequencies, and wherein the reading is performed hierarchically based on the processing circuitry being configured to:
• read the touch sensor at a first resolution that is less than a full resolution, based on logically subdividing all or a targeted zone of the touch surface into multiple first regions and applying excitation frequencies on a per first region basis, each first region involving multiple column lines or row lines;
• and
• responsive to detecting a touch input in a particular one of the first regions, perform one or more further readings of the touch sensor to discriminate a touch location of the touch input at the full resolution, each further reading based on further subdividing the particular first region by allocating one or more additional excitation frequencies for column or row excitation within the particular first region.