Abstract: A processing system for a capacitive input device is described. The capacitive input device includes a plurality of sensor electrodes configured to detect input objects in a sensing region. The processing system configured to transmit a signal on a transmitter sensor channel of the capacitive input device. The processing system is also configured to receive the signal on a receiver sensor channel of the capacitive input device, wherein the receiver sensor channel is coupled with an amplifier. The processing system is also configured to determine if a level of interference has been received by the receiver sensor channel in conjunction with receipt of the signal.

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: A differential amplifier has an output and differential first and second inputs. A switch disposed between a sensor electrode and the second input is opened to initiate a reset phase where the sensor electrode and the differential amplifier are decoupled. A feedback capacitance disposed between the second input and the output is reset to a first level of charge. The switch is closed to initiate a measurement phase where the second input and sensor electrode are coupled. In the measurement phase: charge is balanced between the sensor electrode and the feedback capacitance such that a sensor electrode voltage equals a voltage of the first input equals a voltage of the second input, and the sensor electrode is charged; and the differential amplifier is utilized to integrate charge on the sensor electrode, such that an absolute capacitance corresponding to a coupling between the sensor electrode and an input object is measured.

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: Time synchronization between a central wireless communication device and a peripheral wireless communication device is described. Events associated with an application are time stamped at the central wireless communication device, and one or more link layer messages are sent to the peripheral wireless communication device to provide time stamp information to replicate the event timing at the peripheral wireless communication device. A first link layer message includes information about an internal Bluetooth clock to calibrate a corresponding internal clock value at the peripheral wireless communication device. A second link layer message includes information about a current value for the Bluetooth clock and also a value for an offset that provides a time position at a finer granularity than the Bluetooth clock within a timeslot specified by the Bluetooth clock value.

Abstract: A touch panel electrode structure for user grounding correction in a touch panel is discloses. The electrode structure can include an array of electrodes for sensing a touch at the panel, and multiple jumpers for selectively coupling groups of the electrodes together to form electrode rows and columns that cross each other. In some examples, the array can have a linear configuration and can form the rows and columns by coupling diagonally adjacent electrodes using the jumpers in a zigzag pattern, or the array can have a diamond configuration and can form the rows and columns by coupling linearly adjacent electrodes using the jumpers in a linear pattern. In various examples, each electrode can have a solid structure with a square shape, a reduced area with an outer electrode and a physically separate center electrode, a hollow center, or a solid structure with a hexagonal shape.

Abstract: In certain embodiments, 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. At least some of the signals are high-voltage signals generated by a relatively large potential difference compared to a voltage within a voltage range of approximately 1 to approximately 3 volts. The stylus includes a stylus tip, and one or more of the one or more electrodes are disposed at the stylus tip.

Abstract: A touch controller that can configure touch circuitry according to a scan plan, which can define a sequence of scan events to be performed on a touch panel is disclosed. The touch controller can include a configurable transmit section to generate stimulation signals to drive the panel, a configurable receive section to receive and process touch signals from the panel, and a configurable memory to store the touch signals. The touch controller can also include a programmable scan engine to configure the transmit section, the receive section, and the memory according to the scan plan. The touch controller advantageously provides more robust and flexible touch circuitry to handle various types of touch events at the panel. An active stylus that can generate stimulation signals that can be detected by the touch controller during various touch events at the panel is also disclosed.

Abstract: A touch controller that can configure touch circuitry according to a scan plan, which can define a sequence of scan events to be performed on a touch panel is disclosed. The touch controller can include a configurable transmit section to generate stimulation signals to drive the panel, a configurable receive section to receive and process touch signals from the panel, and a configurable memory to store the touch signals. The touch controller can also include a programmable scan engine to configure the transmit section, the receive section, and the memory according to the scan plan. The touch controller advantageously provides more robust and flexible touch circuitry to handle various types of touch events at the panel. An active stylus that can generate stimulation signals that can be detected by the touch controller during various touch events at the panel is also disclosed.

Abstract: A touch controller that can configure touch circuitry according to a scan plan, which can define a sequence of scan events to be performed on a touch panel is disclosed. The touch controller can include a configurable transmit section to generate stimulation signals to drive the panel, a configurable receive section to receive and process touch signals from the panel, and a configurable memory to store the touch signals. The touch controller can also include a programmable scan engine to configure the transmit section, the receive section, and the memory according to the scan plan. The touch controller advantageously provides more robust and flexible touch circuitry to handle various types of touch events at the panel. An active stylus that can generate stimulation signals that can be detected by the touch controller during various touch events at the panel is also disclosed.

Abstract: Self capacitance touch circuits to cancel the effects of parasitic capacitance in a touch sensitive device are disclosed. One circuit can generate a parasitic capacitance cancelation signal that can be injected into touch sensing circuitry to cancel the parasitic capacitance. Another circuit can adjust the phase and magnitude of the parasitic capacitance cancelation signal based on characteristics of channels in the touch sensing circuitry so as to fine tune the parasitic capacitance cancelations. Another circuit can drive a guard plate and touch panel electrodes so as to cancel the parasitic capacitances between the panel and the plate and between the electrodes.

Abstract: A superheterodyne stylus signal receiver for detecting a stylus stimulation signal from a stylus is provided. The stylus signal receiver can be configured to convert the touch signal into an intermediate frequency signal having a frequency that is less than that of the touch signal. In some examples, a hardware-implemented I-phase demodulator can be used to convert the touch signal into the intermediate frequency signal. The receiver can be further configured to perform IQ demodulation on the intermediate frequency signal at the intermediate frequency signal's lower frequency. In some examples, the IQ demodulation can be performed in firmware.

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: A touch input device configured to synchronize a stylus acquisition process with both a touch data acquisition process and a display refresh process is provided. The touch input device can include one or more processors that can synchronize the stylus data acquisition process to the touch data acquisition process by coordinating stylus scans to take place in between touch scans. The one or more processors can also virtual data banks to synchronize both the touch data acquisition and the stylus scan acquisition with the display refresh process.

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 stylus has 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. At least some of the signals comprise substantially high voltage. The stylus has one or more electrodes in or on a tip of the stylus which transmit the high-voltage signals to the device.

Abstract: A touch input device configured to detect stylus signals generated by an external stylus is provided. The touch input device includes a plurality of stylus signal detectors that receive at its input a combination of stylus receive channels that are combined in a manner to minimize noise while at the same time keeping the stylus signal strength uniform independent of the position of the stylus on the device.

Abstract: A touch input device configured to detect stylus signals generated by an external stylus is provided. The touch input device includes a plurality of stylus signal detectors that can receive the stylus signal and estimate the start and end time of the stylus signal in order to facilitate windowed demodulation of signal. The start and end times are then used to facilitate a windowed demodulation of the stylus signal.

Abstract: A touch input device configured to detect stylus signals generated by an external stylus is provided. The touch input device includes a plurality of stylus signal detectors that can receive the stylus signal and estimate the start and end time of the stylus signal in order to facilitate windowed demodulation of signal. The touch input device also includes circuitry to determine which of the plurality of detectors is most likely to have received the stylus signal and based on that determination can demodulate the signal and extract data embedded within the stylus signal.