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, a method comprises detecting, by a hardware accelerator, that a value has been written to a first location of a memory, the first location identified by a first address. The method further includes adding the value to an accumulated value stored in an accumulator register of the hardware accelerator and storing the result in the accumulator register. The method further includes comparing the value to a maximum value stored in a first register of the hardware accelerator and overwriting the maximum value with the value if the value is greater than the maximum value. The method also includes comparing the value to a minimum value stored in a second register of the hardware accelerator and overwriting the minimum value with the value if the value is less than the minimum value.

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, 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 multi-channel capacitive sensor comprises a sample capacitor having first and second terminals, a first diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a first sense electrode, and a second diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a second sense electrode. The sample capacitor and diodes are coupled to a control circuit. The control circuit is operable to apply a drive signal to the first terminal of the sample capacitor while simultaneously applying a bias signal to the second terminal of one or other of the diodes to prevent the diode from conducting the drive signal.

Abstract: In certain embodiments, a multi-channel capacitive sensor for measuring capacitances of sense electrodes to a system reference potential comprises a sample capacitor having first and second terminals. The sensor comprises a first diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a first sense electrode, and comprises a second diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a second sense electrode. A control circuit is operable to apply a drive signal to the first terminal of the sample capacitor and apply a bias signal to the respective second terminals of at least one of the first and second diodes so as to selectively prevent the at least one of the first and second diodes from conducting the drive signal to respectively connected sense electrodes.

Abstract: A multi-channel capacitive sensor for measuring the capacitances of a plurality of sense electrodes to a system reference potential. The sensor comprises a sample capacitor having a first terminal and a second terminal, a first diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a first sense electrode, and a second diode having a first terminal coupled to the second terminal of the sample capacitor and a second terminal coupled to a second sense electrode. The sample capacitor and diodes are coupled to a control circuit, e.g. implemented in a microcontroller. The control circuit is operable to apply a drive signal, e.g. a series of voltage pulses, to the first terminal of the sample capacitor while simultaneously applying a bias signal to the second terminal of one or other of the diodes to prevent the diode from conducting the drive signal.