Abstract: In one embodiment, a method for determining the location of a touch on a touch sensor includes receiving input signals in response to a touch proximate to a location on the touch sensor. Each input signal may have a total capacitance that includes a first capacitance associated with the touch and a second capacitance that is parasitic capacitance. The parasitic capacitance of one or more of the input signals may be adjusted to result in the second capacitance of each of the input signals being substantially equal. An average capacitance of the adjusted input signals may be calculated. The location of the touch on the touch sensor may then be determined based on a comparison of the total capacitance of each of the input signals and the average capacitance of the input signals.

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 stylus includes one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for transmitting signals wirelessly to a device through a touch sensor of the device. The stylus also includes inductive-charging components in or on the stylus for charging or powering the stylus with electromagnetic radiation from inductive-charging components in or on the device. The inductive-charging components in or on the stylus may also charge or power the device by transmitting electromagnetic radiation to the inductive-charging components in or on 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.

Abstract: In certain embodiments, an apparatus includes a touch sensor that includes a touch-sensitive area and a touch-sensor controller. The touch-sensor controller is operable to: select a first region around a determined first location associated with an object within the touch-sensitive area, select a second region around the determined first location associated with the object within the touch-sensitive area, and scan two or more electrodes within the first region and two or more electrodes within the second region to determine a second location associated with the object within the touch-sensitive area.

Abstract: In one embodiment, a stylus includes one or more electrodes and one or more computer-readable non-transitory storage media embodying logic for transmitting signals wirelessly from the stylus to a device through a touch sensor of the device. The stylus has one or more sensors for kinetic, thermal, solar or electric energy harvesting from an environment of the stylus or from the stylus itself.

Abstract: In one embodiment, a method includes driving at least two of multiple drive lines of a touch sensor at a time, each with one or more electrical pulses.

Abstract: In one embodiment, an apparatus comprises a touch sensor comprising a touch-sensitive area, and a touch-sensor controller coupled to the touch sensor. The touch-sensor controller is operable when executed to: select one or more regions associated with a stylus within the touch-sensitive area, and scan one or more electrodes within each region.

Abstract: In one embodiment, an apparatus includes a drive electrode, a sense electrode, a detector, and a controller. The drive electrode is stimulated by an electric signal that has a frequency that varies in time. The sense electrode is capacitatively coupled to the drive electrode. The detector performs a measurement associated with the sense electrode. The controller determines whether a touch on the touch sensor occurred by determining whether the measurement deviates from an expected value by more than an amount.

Abstract: In one embodiment, a method comprises generating, by a controller, a plurality of drive signals. The method further includes simultaneously transmitting, by the controller, the plurality of drive signals to a plurality of drive electrodes disposed on a touch sensor. The method further includes sensing a sense electrode of a plurality of sense electrodes disposed on the touch sensor. The sensing comprises measuring, for each drive electrode of the plurality of drive electrodes, at least one value indicative of a capacitance between the sense electrode and the drive electrode.

Abstract: A method of one embodiment includes generating, by a stylus, a composite signal. The composite signal includes a first signal having a first frequency, the first signal being used by a touch-sensing device to determine a position of the stylus relative to the touch-sensing device, and a second signal having a second frequency. The second signal may include status information such as an amount of force exerted on the stylus, battery information, orientation information, information indicating whether the stylus is within a threshold distance of the touch-sensing device, information indicating a status of a button of the stylus, and/or information indicating input from a user of the stylus. Furthermore, the second frequency is higher than the first frequency. The stylus sends the composite signal to the touch-sensing device, and an electrode array of the touch-sensing device may receive the composite signal.

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: A method of one embodiment includes generating, by a touch-sensing device, a first signal comprising information identifying a first electrode line of an electrode array of the touch-sensing device, the first signal having a first strength. The first electrode sends the first signal to a stylus, which receives the first signal, the first signal having a received strength. The stylus sends a second signal comprising information based on the received first signal, and the touch-sensing device receives the second signal. A position of the stylus is determined based at least in part on the information identifying the first electrode line and the received strength of the first signal.

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 modifying an amount of charge of a capacitance of a touch sensor. The modified amount of charge results 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 modifies 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 voltage at a sampling capacitor. The first voltage is proportional to a difference between the first charging voltage level and a reference voltage level. The method also includes determining whether a touch and stylus input to the touch sensor has occurred based on the first voltage and a second voltage.

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: A single-wire bootloader software architecture is disclosed that interfaces with any host device that has a serial port to program memory of a target device using only a single general-purpose I/O pin. The single-wire bootloader does not require any chip hardware resource modules. Instead, the single-wire bootloader implements a single-wire UART in software that monitors a single general-purpose I/O pin for commands from the host device.

Abstract: In one embodiment, a method includes receiving at a stylus a receive signal from a device. The stylus includes one or more computer-readable media embodying logic, and the device includes a touch sensor. The receive signal is received at the stylus through the touch sensor of the device and one or more electrodes of the stylus. The method includes determining whether a level of the receive signal substantially meets or exceeds a pre-determined threshold; if the level of the receive signal substantially meets or exceeds the pre-determined threshold, then transmitting the receive signal to the logic for processing; and, if the level of the receive signal does not substantially meet or exceed the pre-determined threshold, then filtering out the receive signal from processing by the logic.

Abstract: In one embodiment, a system comprises a stylus and a touch sensor. The stylus is operable to transmit a first signal. The touch sensor comprises a first plurality of electrode lines and a controller. Each electrode line is operable to sense the first signal transmitted by a stylus. The stylus tip of the stylus is located at a position relative to the first plurality of electrode lines at the time of transmission of the first signal. The controller is operable to measure a voltage, charge, or capacitance of the sensed first signal on each electrode line of the first plurality of electrode lines and estimate the position of the stylus tip based on interpolation of the measured voltages on each electrode line of the first plurality of electrode lines.

Abstract: In one embodiment, a method includes detecting movement of a spring structure of a force sensor coupled to a center shaft of an active stylus; measuring a change of capacitance between electrodes of the force sensor; and determining an amount of force applied to the center shaft based on the change of capacitance.