Abstract: A touch-sensitive display device includes a touch sensor having a plurality of display electrodes and control logic coupled to the plurality of display electrodes. The control logic is configured to receive, for each of a plurality of stylus electrodes of an active stylus interacting with the touch-sensitive display device, a spatial capacitance measurement over the touch sensor for that stylus electrode. Relative to the touch sensor, and based on spatial capacitance measurements of the stylus electrodes, the control logic is configured to determine (i) a tip position of the active stylus, (ii) a tilt parameter of the active stylus, and (iii) a twist parameter of the active stylus.

Abstract: An active stylus includes a stylus electrode, receive circuitry, and transmit circuitry. The stylus electrode is configured to capacitively couple with one or more electrodes of a capacitance-based touch sensor of a touch-sensitive device. The receive circuitry is operatively coupled to the stylus electrode and configured to receive a synchronization waveform from the touch-sensitive device. The transmit circuitry is operatively coupled to the stylus electrode and configured to, upon receiving the synchronization waveform, transmit stylus information to the touch-sensitive device according to a communication frame including a first set of sub-frames and a second set of sub-frames. The transmit circuitry is configured to transmit a first waveform during the first set, if the active stylus is hovering, transmit the first waveform during the second set, and if the active stylus is not hovering, transmit one or more additional waveforms during the second set.

Abstract: A source touch display device includes a communication interface, a source touch sensor, and a controller. The communication interface is configured to communicatively couple the source touch display device with a target touch display device. The controller configured to receive, via the source touch sensor, touch inputs from an active input device, determine that the active input device will likely move from the source touch sensor to a target touch sensor of the neighboring target display device based on the touch inputs, send, via the communication interface, active input device pairing information to the target touch display device, receive, via the communication interface, target touch display device pairing information from the target touch display device, and send the target touch display device pairing information to the active input device to effect a pairing between the active input device and the target touch display device.

Abstract: A touch-sensitive display device includes a touch sensor having a plurality of display electrodes and control logic coupled to the plurality of display electrodes. The control logic is configured to receive, for each of a plurality of stylus electrodes of an active stylus interacting with the touch-sensitive display device, a spatial capacitance measurement over the touch sensor for that stylus electrode. Relative to the touch sensor, and based on spatial capacitance measurements of the stylus electrodes, the control logic is configured to determine (i) a tip position of the active stylus, (ii) a tilt parameter of the active stylus, and (iii) a twist parameter of the active stylus.

Abstract: A touch-sensitive device includes a touch sensor including a plurality of electrodes and receive circuitry configured to interpret a response on one or more electrodes of the plurality of electrodes based on stylus waveforms being driven on a stylus electrode of an active stylus. The touch-sensitive device is configured to correlate the stylus waveforms with one or more reference waveforms to produce correlation magnitudes; The touch-sensitive device is further configured to map each correlation magnitude to a demodulation symbol selected from a plurality of demodulation symbols of a one-dimensional, non-uniform constellation. Each demodulation symbol encodes multiple data bits. The touch-sensitive device is further configured to decode the mapped demodulation symbols to determine a plurality of data bits of stylus information of the active stylus.

Abstract: Examples are disclosed herein that relate to reducing noise in received signals. An example provides a method comprising receiving, via one or more electrodes of an input device, a capacitive signal, for each of two or more reference sequences designed for a respective capacitive signal condition, correlating the capacitive signal with the reference sequence, and identifying a particular one of the two or more reference sequences that produced a highest noise immunity when correlated with the capacitive signal. The method may further comprise correlating the identified reference sequence with a subsequent capacitive signal to thereby receive information in the subsequent capacitive signal regarding an input device condition.

Abstract: A touch-sensitive display device includes a touch sensor having a plurality of display electrodes and control logic coupled to the plurality of display electrodes. The control logic is configured to receive, for each of a plurality of stylus electrodes of an active stylus interacting with the touch-sensitive display device, a spatial capacitance measurement over the touch sensor for that stylus electrode. Relative to the touch sensor, and based on spatial capacitance measurements of the stylus electrodes, the control logic is configured to determine (i) a tip position of the active stylus, (ii) a tilt parameter of the active stylus, and (iii) a twist parameter of the active stylus.

Abstract: An active stylus includes a stylus electrode, receive circuitry, and transmit circuitry. The stylus electrode is configured to capacitively couple with one or more electrodes of a capacitance-based touch sensor of a touch-sensitive device. The receive circuitry is operatively coupled to the stylus electrode and configured to receive a synchronization waveform from the touch-sensitive device. The transmit circuitry is operatively coupled to the stylus electrode and configured to, upon receiving the synchronization waveform, transmit stylus information to the touch-sensitive device according to a communication frame including a first set of sub-frames and a second set of sub-frames. The transmit circuitry is configured to transmit a first waveform during the first set, if the active stylus is hovering, transmit the first waveform during the second set, and if the active stylus is not hovering, transmit one or more additional waveforms during the second set.

Abstract: An active stylus includes a stylus electrode configured to electrostatically couple with one or more electrodes of a display device having a capacitance-based touch sensor, transmit logic configured to drive the stylus electrode with a synchronization waveform that is configured, via interpreting a response on one or more electrodes of a first display device, to enable the first display device to become time synchronized with the active stylus in a stylus-initiated synchronization mode, receive logic configured to interpret a response on the stylus electrode caused by a synchronization waveform being driven on one or more electrodes of a second display device, to enable the active stylus to become time synchronized with the second display device in a display-initiated synchronization mode, and a controller configured, in response to detection of a condition, to cause the active stylus to switch from one of the synchronization modes to the other.

Abstract: A touch-sensitive device includes a capacitance-based touch sensor, drive circuitry configured to drive touch sensor electrodes with a synchronization waveform to enable an active stylus to become time synchronized with the touch-sensitive device, and receive circuitry configured to determine a position of the active stylus based on electrostatically receiving a first waveform from the active stylus. Depending on when the touch-sensitive device receives the first waveform from the active stylus, the touch-sensitive device interprets the first waveform differently to determine a position of the active stylus or determine that the active stylus is hovering. In either case, the same waveform is used to communicate different information about the active stylus to the touch-sensitive device.

Abstract: Examples are disclosed herein that relate to communication between a capacitive touch sensor and an active stylus. An example provides an active stylus comprising an electrode tip, and receive circuitry coupled to the electrode tip. The receive circuitry may be configured to receive a capacitive signal from a touch sensor through the electrode tip, determine which of two or more drive signals produced by respective regions of the touch sensor most strongly influenced the capacitive signal, each drive signal being associated with a different operating mode, and configure one or both of the active stylus and the touch sensor to operate in the operating mode associated with the determined drive signal.

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-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: Examples are described for touch-sensitive displays in which ground references for associated electronics are isolated from one another. In one example, a touch-sensitive display includes a display panel, and a touch sensor, the touch sensor including a receive electrode, the touch sensor including a transmit electrode, the receive electrode and the transmit electrode overlaying the display panel, and wherein a ground reference of the receive and/or the transmit electrode is isolated from a ground reference of the display panel, thereby creating a transmission-inhibiting communication boundary between the display panel and the touch sensor, the touch sensor communicatively connected to the display panel so as to exchange data between ground domains separated by the boundary.

Abstract: A touch-sensitive display device includes a touch sensor having a plurality of touch-sensing electrodes and control logic coupled to the plurality of touch-sensing electrodes. The control logic is configured to, in a non-reference time frame and based on a spatial capacitance measurement received for a first stylus electrode of an active stylus, estimate a non-reference time frame location of the first stylus electrode relative to the plurality of touch-sensing electrodes. In a reference time frame, based on a spatial capacitance measurement received for a second stylus electrode of the active stylus, a reference time frame location of the second stylus electrode is estimated. Based on an estimated velocity of the first stylus electrode, the non-reference location of the first stylus electrode is velocity corrected to give a reference time frame location of the first stylus electrode.

Abstract: A touch-sensing system is disclosed. The system includes a display device including a touch sensor having a plurality of electrodes, and drive logic coupled to the plurality of electrodes and configured to drive the plurality of electrodes during a plurality of touch-sensing frames, each of which includes a stylus sync sub-frame during which the drive logic drives at least some of the plurality of electrodes, referred to for that stylus sync sub-frame as sync-driven electrodes, with synchronization waveforms that are communicated electrostatically to cause synchronization of the display device with an active stylus. For each of the stylus sync sub-frames, the drive logic may be configured to differentially drive the sync-driven electrodes of such stylus sync sub-frame, such that a first synchronization waveform used to drive one of the sync-driven electrodes is different than a second synchronization waveform used to drive another of the sync-driven electrodes.

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 establish a timing scheme shared between the active stylus and 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 the shared timing scheme.

Abstract: Examples are disclosed herein that relate to capacitive touch sensor operation. An example provides a method for operating a display system having a capacitive touch sensor comprising operating the touch sensor over a plurality of successively repeating touch frames, with the touch sensor, determining a motion vector for an active stylus in relation to the touch sensor, and in each of the touch frames, for a stylus-interaction sub-frame of that touch frame allocated for performing electrostatic interaction between an active stylus and the touch sensor, selecting a portion of the touch sensor based on the motion vector. In each of the stylus-interaction sub-frames, the selected portion of the touch sensor may be operated differently than other portions of the touch sensor to carry out the electrostatic interaction.

Abstract: Examples are disclosed herein that relate to hover sensing. One example provides a hover sensor comprising an electrode array including a first electrode subset and a second electrode subset, each electrode in the first electrode subset coupled to a corresponding electrode in the second electrode subset at a respective node and separated from the corresponding electrode by a gap, a charge circuit configured to charge the first electrode subset substantially oppositely about a reference voltage to the second electrode subset, an integration circuit configured to, for each respective node, store a net charge on a capacitor and provide an output voltage based on the net charge stored on the capacitor, and a controller. The controller is configured to indicate a presence of a hover object responsive to identifying at least a threshold voltage change based on a sample of the output voltage.

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.