Abstract: A touch-sensitive display device includes a touch sensor, drive circuitry and receive circuitry. The touch sensor has a matrix of row electrodes and column electrodes. The drive circuitry drives the row electrodes during a touch-sensing frame to influence electrical conditions on the column electrodes. The receive circuitry, during the touch-sensing frame, for each row electrode of the matrix, measures a capacitance of each column electrode while the row electrode is being driven, for each of a plurality of different sections of column electrodes of the matrix, performs local analysis of the measured capacitances of the column electrodes of the section to estimate a row-specific noise capacitance for each column electrode, and determines a touch input based on a difference between the measured capacitance of the column electrode while the row electrode is being driven and the estimated row-specific noise capacitance of the column electrode.

Abstract: A touch-sensing system is disclosed. The system includes a display device having a touch sensor with a matrix of row electrodes and column electrodes. Drive logic drives the row electrodes in a plurality of stylus sync sub-frames. In each, some row electrodes, referred to for that stylus sync sub-frame as sync-driven row electrodes, are driven by the drive logic with synchronization waveforms to synchronize the display device with an active stylus. For each stylus sync sub-frame, the sync-driven row electrodes are differentially driven by the drive logic, in the sense that a synchronization waveform used to drive one of the sync-driven row electrodes is different than a synchronization waveform used to drive another of the sync-driven row electrodes.

Abstract: Embodiments are disclosed that relate to touch input detection in a touch sensor. One example provides a method comprising establishing a first reference sequence, starting with a first set of candidate reference sequences each differing from the first reference sequence, reducing the first set of candidate reference sequences by applying a rule set to the first set to derive a relatively smaller second set of candidate reference sequences, for each candidate reference sequence in the second set of candidate reference sequences, calculating a touch detection performance score of a combined reference sequence, and configuring at least a portion of a receive circuit to correlate signals to at least one of the touch detection conditions by using the first reference sequence in a combined correlation operation with at least a selected candidate reference sequence from the second set of candidate reference sequences.

Abstract: A touch sensor is provided having a matrix of row electrodes and column electrodes. Associated circuitry progressively drives the row electrodes in successive touch-sensing frames, and the resulting signals on the column electrodes are processed to detect touch events. In each interval of each touch-sensing frame, a different grouping of the row electrodes is driven. Within each interval, the associated grouping is driven in multiple differently-driven drive states. For a set of possible touch events associated with the row electrodes of the grouping, the drive states produce differing drive state outputs that collectively, but not individually, are usable to detect each of the different touch events.

Abstract: Embodiments are disclosed that relate to touch input detection in a touch sensor. One example provides a method comprising establishing a first reference sequence, starting with a first set of candidate reference sequences each differing from the first reference sequence, reducing the first set of candidate reference sequences by applying a rule set to the first set to derive a relatively smaller second set of candidate reference sequences, for each candidate reference sequence in the second set of candidate reference sequences, calculating a touch detection performance score of a combined reference sequence, and configuring at least a portion of a receive circuit to correlate signals to at least one of the touch detection conditions by using the first reference sequence in a combined correlation operation with at least a selected candidate reference sequence from the second set of candidate reference sequences.

Abstract: An active stylus includes an electrode and a controller. The controller is configured to 1) generate a report including stylus information represented by a plurality of bits including a first subset of bits and a second subset of bits, 2) encode the first set of bits differently than the second set of bits to reduce a size of the report, and 3) excite the electrode with a carrier signal to form an electrostatic communication channel, the carrier signal being modulated to transmit the report via the electrostatic communication channel.

Abstract: A touch-sensing system is disclosed. The system includes a display device having a touch sensor with a matrix of row electrodes and column electrodes. Drive logic drives the row electrodes in a plurality of stylus sync sub-frames. In each, some row electrodes, referred to for that stylus sync sub-frame as sync-driven row electrodes, are driven by the drive logic with synchronization waveforms to synchronize the display device with an active stylus. For each stylus sync sub-frame, the sync-driven row electrodes are differentially driven by the drive logic, in the sense that a synchronization waveform used to drive one of the sync-driven row electrodes is different than a synchronization waveform used to drive another of the sync-driven row electrodes.

Abstract: Embodiments are disclosed that relate to touch input detection in a touch sensor. One example provides a method comprising establishing a first reference sequence, starting with a first set of candidate reference sequences each differing from the first reference sequence, reducing the first set of candidate reference sequences by applying a rule set to the first set to derive a relatively smaller second set of candidate reference sequences, for each candidate reference sequence in the second set of candidate reference sequences, calculating a touch detection performance score of a combined reference sequence, and configuring at least a portion of a receive circuit to correlate signals to at least one of the touch detection conditions by using the first reference sequence in a combined correlation operation with at least a selected candidate reference sequence from the second set of candidate reference sequences.

Abstract: A touch-sensing system for use with a display system is provided herein. The touch-sensing system includes: (1) a first touch-sensor matrix having rows and columns and situated planarly relative to the display system; (2) a second touch-sensor matrix having rows and columns and situated planarly relative to the display system; and (3) a drive subsystem coupled to the rows of the first touch-sensor matrix and to the rows of the second touch-sensor matrix. Within each of a plurality of touch-sense frames, the drive subsystem serially drives the rows of each of the touch-sensor matrices in a differential drive manner, in which a first drive signal is used for the rows of the first touch-sensor matrix and a second drive signal, different from the first, is used for the rows of the second touch-sensor matrix.

Abstract: A touch-sensing system comprises an active stylus including a probe electrode and associated sensory logic. The sensory logic is configured to receive a synchronization pulse sequence via the probe electrode between consecutive touch-sensing frames of a capacitive touch screen, to use the synchronization pulse sequence to synchronize a local row counter of the sensory logic to a remote row counter of the capacitive touch screen, to receive an excitation pulse via the probe electrode within a given touch-sensing frame, and to use the excitation pulse to maintain synchronization between the local row counter and the remote row counter.