Abstract: A system of one embodiment includes a touch-sensing device and a stylus. The touch sensing device includes an electrode array, which includes a plurality of electrode line pairs, and a controller. Each electrode line pair includes a first and second electrode line to send a first and second signal, respectively. The stylus includes a sensor to measure the first and second signals, a signal processor to determine position information, and a transmitter to send position information to the touch-sensing device. A method of another embodiment includes sending, by a first electrode line, a first signal having a first frequency. A second electrode line sends a second signal having a second frequency. A stylus receives the first and second signals. The stylus sends a response signal to the touch-sensing device based on the first and second signals. A position of the stylus is determined based on the first and second signals.

Abstract: Position-based sensing methods and systems can be used to transmit data from an input device to a touch-sensitive device. For example, the touch sensing system may perform one or more coarse input device sub-scans to determine a coarse location of the input device. The coarse location can be used to select one or more touch sensors (or sensor channels) to sample for decoding data encoded in the stimulation signals from the input device. During one or more fine input device sub-scans, the touch sensing system can determine a fine location of the input device and decode the data from the input device sampled from the selected touch sensors (or sensor channels).

Abstract: An interference determining circuit for a capacitive sensor device comprises an amplifier, absolute differential circuitry, and comparator circuitry. The amplifier is configured for receiving a reference voltage at a first input and for receiving a resulting signal at a second input. The resulting signal is from a sensor electrode of the capacitive sensor device. The absolute differential circuitry is coupled with an output of the amplifier and configured for outputting a difference signal. The difference signal represents an absolute differential between currents utilized in the amplifier. The comparator circuitry is coupled with the absolute differential circuitry and configured for generating a non-linearity indication based on a comparison of the difference signal with at least one reference signal.

Abstract: In one embodiment, a method includes receiving a request to refresh a display for a refresh period, wherein the display is coupled to a touch sensor operable to detect touch input at the display. During a first phase of the refresh period, a first portion of the display is refreshed while the touch sensor a second portion and a third portion of the display is activated. The second portion and the third portion are a half screen distance apart. During a second phase of the refresh period, the second portion of the display is refreshed while the touch sensor at a fourth portion and a fifth portion of the display is activated. The fourth portion and the fifth portion are a half screen distance apart.

Abstract: A touch sensor may overlap a display. A transparent shield layer that is grounded around its edges may be interposed between the display and the touch sensor to help prevent noise from display data lines from reaching the touch sensor. The data lines may extend along a first dimension. The touch sensor may have first elongated electrodes that extend along the first dimension and second elongated electrodes that extend along a second dimension that is perpendicular to the first dimension. The second electrodes may be interposed between the first electrodes and the data lines. Pen present electrodes may be used to gather pen present data associated with a stylus on the touch sensor. Adjacent noise sensors may collect noise data that is removed from the pen present data.

Abstract: Active styli, methods and non-transitory computer readable storage media can be used for mitigating noise coupling from an active stylus to a touch sensing system. An active stylus can include a force sensor that can be used to detect stylus touch-down and lift-off events. Based on a touch-down and lift-off events, the stylus can generate stimulation signals and ramp up or ramp down the amplitude of the stimulation signals. Additionally or alternatively, an active stylus can receive information to synchronize the active stylus with a touch-sensitive device. Based on the information, the stylus can synchronize generation of stimulation signals with the stylus scan performed by the touch-sensitive device. The stimulation signals can be ramped up during a guard band period before a stylus scan and can be ramped down during a guard band period after the stylus scan.

Abstract: In one embodiment, a method includes receiving a request to refresh a display for a refresh period, wherein the display is coupled to a touch sensor operable to detect touch input at the display. During a first phase of the refresh period, a first portion of the display is refreshed while the touch sensor a second portion and a third portion of the display is activated. The second portion and the third portion are a half screen distance apart. During a second phase of the refresh period, the second portion of the display is refreshed while the touch sensor at a fourth portion and a fifth portion of the display is activated. The fourth portion and the fifth portion are a half screen distance apart.

Abstract: Electrode configurations for reducing wobble error for a stylus translating on a surface over and between electrodes of a touch sensor panel is disclosed. In some examples, electrodes associated with a more linear signal profile are correlated with lower wobble error. In some examples, electrodes are coupled to adjacent electrodes via diffusing resistors such that the signal profile for each electrode is spread to be more linear. In some configurations, the value of the diffusing resistors and series resistance associated with an electrode is selected based on a desired signal profile for that electrode. In some examples, the series resistance can include a trace resistance and a compensating resistance. The compensating resistance can compensate for a variance in trace resistance between electrodes, thus making series resistance substantially equal for each of the electrodes.

Abstract: Algorithms can be used to reduce stylus tip wobble for a stylus translating on a surface over and between electrodes of a touch sensor panel. In some examples, a first position estimate can be calculated using a first position calculation method and a second position estimate can be calculated using a second position calculation method. The position of the stylus can be determined based on a weighted combination of the first and second position estimates. In some examples, the first position estimate can be calculated using an even-point centroid of signal contributions from an even number of electrodes of a touch sensor panel and the second position estimate can be calculated using an odd-point centroid of signal contributions from an odd number of electrodes. In some examples, the weighting can be assigned based on a ratio of the two largest amplitude signals and based on a ratio of the second and third largest amplitude signals.

Abstract: In one embodiment, a method includes receiving a request to refresh a display for a refresh period, wherein the display is coupled to a touch sensor operable to detect touch input at the display. The method also includes refreshing a first portion of the display and activating the touch sensor at a second portion of the display different from the first portion of the display during a first portion of the refresh period. The method further includes, during a second portion of the refresh period, refreshing a third portion of the display different from the first and second portions of the display and activating the touch sensor at a fourth portion of the display different from the first, second, and third portions of the display.

Abstract: A multi-chip touch architecture for scalability can include one or more touch controller application specific integrated circuits (ASICs), and one or more switching circuits coupled between the one or more touch controller ASICs and the touch sensor panel. The number of touch controller ASICs and switching circuits can be scaled based on the size of the touch sensor panel. The touch controller ASICs can include an interface for data transfer between the touch controller ASICs to allow for parallel processing of an image of touch by more than one touch controller ASIC. The touch controller ASIC can also include a memory directly accessible by more than one processing circuit (e.g., hardware accelerators), and circuitry to dynamically adjust the coupling between portions (e.g., banks) of memory and inputs of the one or more processing circuits to minimize data transfer and improve processing speeds.

Abstract: In one embodiment, a method includes modifying an amount of charge of a capacitance of a touch sensor. The modified amount of charge resulting in a voltage at the capacitance being a first pre-determined voltage level. The method also includes applying a first pre-determined amount of charge to the capacitance. The application of the first pre-determined amount of charge to the capacitance modifying the voltage at the capacitance from the first pre-determined voltage level to a first charging voltage level. The method also includes determining a first difference between the first charging voltage level and a reference voltage level; and determining whether a touch input to the touch sensor has occurred based on the first difference.

Abstract: Power consumption of touch sensing operations for touch sensitive devices can be reduced by implementing a coarse scan (e.g., banked common mode scan) to coarsely detect the presence or absence of an object touching or proximate to a touch sensor panel and the results of the coarse scan can be used to dynamically adjust the operation of the touch sensitive device to perform or not perform a fine scan (e.g., targeted active mode scan). In some examples, the results of the coarse scan can be used to program a touch controller for the next touch sensing frame to idle when no touch event is detected or to perform a fine scan when one or more touch events are detected. In some examples, the results of the coarse scan can be used to abort a scheduled fine scan during the current touch sensing frame when no touch event is detected.

Abstract: Power consumption of touch sensing operations for touch sensitive devices can be reduced by implementing one or more coarse scans to coarsely detect the presence or absence of an object touching or proximate to a touch sensor panel and dynamically adjusting the operation of the touch sensitive device to perform or not perform one or more steps of a fine scan based on the results of the one or more coarse scans. In some examples, the fine scan can be scheduled, and one or more steps of the fine scan can be aborted when no touch is detected at touch sensors scanned during the one or more steps. Sense channels unused due to the aborted fine scan steps can be powered down during aborted fine scan steps.

Abstract: A touch sensor may overlap a display. A transparent shield layer that is grounded around its edges may be interposed between the display and the touch sensor to help prevent noise from display data lines from reaching the touch sensor. The data lines may extend along a first dimension. The touch sensor may have first elongated electrodes that extend along the first dimension and second elongated electrodes that extend along a second dimension that is perpendicular to the first dimension. The second electrodes may be interposed between the first electrodes and the data lines. Pen present electrodes may be used to gather pen present data associated with a stylus on the touch sensor. Adjacent noise sensors may collect noise data that is removed from the pen present data.

Abstract: In one embodiment, a method includes receiving sensor data from one or more sensors in or on a stylus, the stylus including one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for wirelessly transmitting signals to a device through a touch sensor of the device. The method includes generating a carrier signal and modulating the carrier signal to communicate the sensor data and wirelessly transmitting from the stylus to the device the carrier signal as modulated through the touch sensor of the device.

Abstract: An algorithm for reducing stylus tip wobble for a stylus translating on a surface over and between electrodes of a touch sensor panel is disclosed. In some examples, a first position estimate can be calculated using a first position calculation method and a second position estimate can be calculated using a second position calculation method. The position of the stylus can be determined based on a weighted combination of the first and second position estimates. In some examples, the first position estimate can be calculated using an even-point centroid of signal contributions from an even number of electrodes of a touch sensor panel and the second position estimate can be calculated using an odd-point centroid of signal contributions from an odd number of electrodes. In some examples, the weighting can be assigned based on a ratio of the two largest amplitude signals and based on a ratio of the second and third largest amplitude signals.

Abstract: In one embodiment, a stylus receives a signal, the stylus being able to wirelessly transmit signals to and receive signals from a device, and the stylus having a plurality of electrodes disposed in a tip of the stylus. The stylus compares a first value of the signal to a first threshold and determines whether to start a timing period based at least in part on this comparison. If the timing period is started, the stylus compares a second value of the signal to a second threshold and determines whether to stop the timing period based at least in part on this second comparison. If the timing period is stopped, the stylus determines whether the duration of the timing period is within a pre-determined range of timing period values. If so, the stylus processes the signal.

Abstract: In one embodiment, a method includes receiving sensor data from one or more sensors in or on a stylus, the stylus including one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for wirelessly transmitting signals to a device through a touch sensor of the device. The method includes generating a carrier signal and modulating the carrier signal to communicate the sensor data and wirelessly transmitting from the stylus to the device the carrier signal as modulated through the touch sensor of the device.

Abstract: In one embodiment, a method includes receiving sensor data from one or more sensors in or on a stylus, the stylus including one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for wirelessly transmitting signals to a device through a touch sensor of the device. The method includes generating a carrier signal and modulating the carrier signal to communicate the sensor data and wirelessly transmitting from the stylus to the device the carrier signal as modulated through the touch sensor of the device.