Abstract: A handheld stylus for use with a display device may include a handheld body, a tip movably coupled to the body, and at least one capacitive sensor configured to detect movements of the tip relative to the body. The at least one capacitive sensor may comprise at least one first conductive element secured to or integral with the body, and at least one second conductive element secured to or integral with the movable tip. The tip may be arranged such that the at least one first conductive element and the at least one second conductive element are spaced apart from each other. The at least one capacitive sensor may be configured to detect changes in respective distances between the at least one first conductive element and the at least one second conductive element caused by movements of the tip relative to the body.

Abstract: A proximity sensing function is implemented using a collection of core independent peripherals (CIPs) in a microcontroller without software overhead to the central processor during operation thereof. A pulse width modulation (PWM) peripheral generates a high frequency drive signal that is on for a short duration to an ultrasonic transmitting transducer. An ultrasonic receiving transducer receives reflected ultrasonic pulses during an integration time window. The received pulses are detected and integrated into a voltage value. The integrated voltage value is compared to a prior voltage value average, and if different, generates a proximity sense signal of an object. Direction, distance and speed of the object may also be determined from the voltage values.

Abstract: A stepper control circuit includes numerical controlled oscillators configured to provide step signals for multiple axes of stepper motor movement. The numerical controlled oscillators are configured to be operated at a same frequency provided by a synchronized clock signal.

Abstract: A door frame has a first electromagnetic coil and a door lock has a second electromagnetic coil with a door bolt electromagnetically coupling together the first and second electromagnetic coils, thereby forming a transformer. Power is transferred from the door frame to door lock through the transformer. Communications from the door frame to the door lock may be provided by modulating electromagnetic energy to the first electromagnetic coil and demodulating the modulated electromagnetic energy received at the second electromagnetic coil. Communications from the door lock to the door frame may be provided by varying a load on the second electromagnetic coil and detecting the load change at the first electromagnetic coil.

Abstract: A ranging function is implemented using a collection of core independent peripherals (CIPs) in a microcontroller without software overhead to the central processor during operation thereof. A pulse width modulation (PWM) peripheral generates a high frequency drive signal, a counter to set the duration of the PWM drive signal (pulse), and a second timer coupled to a comparator to measure the time it takes to receive back a reflection of the ranging signal from an object. The ranging peripheral starts ranging with ultrasonic pulses, and when corresponding reflected ultrasonic pulse are receives an interrupt signal is provided when the ranging measurement is complete. Time dependent sensitivity and/or gain adjustments are contemplated. The ultrasonic ranging peripheral uses on chip resources for most of its functions and therefore requires very few external components. It's set and forget nature may be based on CIP based timers, signal generators and configurable logic cells.

Abstract: Capacitive proximity detection is provided by combining a delta-sigma modulator and a capacitive voltage divider circuit to create a high resolution capacitive-to-digital converter. Period and duty cycle counters provide duty cycle ratios from the delta-sigma modulator for comparison of changes in capacitance values of a capacitive sensor when an object is in proximity thereto.

Abstract: A physical force capacitive touch sensor comprises a capacitive sensor element on a substrate, a physically deformable electrically insulating spacer over the capacitive sensor element and a conductive deformable plane over the physically deformable electrically insulating spacer. A protective deformable fascia may be placed over the conductive deformable plane to provide an environmental seal for physical and weather protection, but is not essential to operation of the capacitive touch sensor. Back lighting is accomplished through a light transmissive layer(s) in the capacitive touch sensor. When the conductive deformable plane is displaced toward the capacitive touch sensor element, the capacitance value of the capacitive touch sensor element changes and that change may be detected and used as an actuation signal.

Abstract: A microcontroller measures capacitance of capacitive sensors having guard rings associated therewith. A guard ring is provided around each capacitive sensor plate and is charged to substantially the same voltage as a voltage on the associated capacitive sensor plate. The guard ring reduces parasitic capacitances of the capacitive sensor plate caused by differences in voltage potentials between the capacitive sensor plate, and adjacent circuit conductors, ground planes and power planes. An analog output is buffered and coupled to an analog input coupled to the capacitive sensor plate, and is used to drive the guard ring voltage to substantially the same voltage as the voltage on the capacitive sensor plate.

Abstract: A three input voltage comparator provides termination of a pulse width modulation (PWM) output in a switched mode power supply. Shutdown of the PWM signal occurs when a sense current from the switching transistors exceeds either or both of the limit and error current references. The three input voltage comparator replaces the generally used two input voltage comparator and also eliminates the necessity of having to provide a voltage clamping circuit on the output of the voltage error amplifier in the switched mode power supply. The three input voltage comparator may also comprise selectable polarity control for more versatile integration of it into a switched mode power supply design.

Abstract: A microcontroller has a CPU with at least one interrupt input coupled with an interrupt controller, a plurality of peripherals, and a mode register comprising at least one bit controlling an operating mode of the microcontroller. The microcontroller is configured to operate in a first operating mode wherein upon assertion of an interrupt by a peripheral of the microcontroller, the interrupt controller forwards an interrupt signal to the CPU and the peripheral sets an associated interrupt flag, wherein the interrupt causes the CPU to branch to a predefined interrupt address associated with the interrupt input. In a second operating mode, upon assertion of an interrupt by a peripheral of the microcontroller, the interrupt controller forwards an interrupt signal to the CPU and the CPU receives additional interrupt information from the peripheral that generated the interrupt, wherein the additional interrupt information is used to generate a vector address.

Abstract: An ion chamber provides a current representative of its characteristics as affected by external conditions, e.g., clean air or smoke. A direct current (DC) voltage is applied to the ion chamber at a first polarity and the resulting current through the ion chamber and parasitic leakage current is measured at the first polarity, then the DC voltage is applied to the ion chamber at a second polarity opposite the first polarity, and the resulting current through the ion chamber and parasitic leakage current is measured at the second polarity. Since substantially no current flows through the ion chamber at the second polarity, the common mode parasitic leakage current contribution may be removed from the total current measurement by subtracting the current measured at the second polarity from the current measured at the first polarity, resulting in just the current through the ion chamber.

Abstract: A microcontroller may comprise a central processing unit coupled with a plurality of peripheral devices through a system bus; and a watchdog timer unit receiving a clear watchdog signal and being configured to generate a watchdog timeout signal for resetting the microcontroller, wherein the watchdog timer unit is further configured to define a first and a second watchdog timeout period through a first and a second timer, respectively, further having logic to select the first or the second timer, wherein the clear watchdog signal resets the first and second timer.

Abstract: A standard two terminal battery package is configured to communicate with an external charger or load, without requiring modification to the battery mechanics and/or high current circuit components integral with the battery. A transmitter and receiver (transceiver) are incorporated into the battery housing. An associated battery charger and/or load, e.g., tool, appliance, vacuum, etc., has a corresponding transceiver configured to communicate with the battery transceiver. A microcontroller may be coupled to the transceiver. Serial number verification between the battery and tool load can be verified. Sensors for temperature, voltage, pressure and pH may be coupled between the battery and microcontroller for monitoring battery temperature, voltage charge and condition during operation or charging thereof. Information from these sensors and more may be communicated from the battery to the load or battery charger.

Abstract: An ion chamber provides a current representative of its characteristics as affected by external conditions, e.g., clean air or smoke. A direct current (DC) voltage is applied to the ion chamber at a first polarity and the resulting current through the ion chamber and parasitic leakage current is measured at the first polarity, then the DC voltage is applied to the ion chamber at a second polarity opposite the first polarity, and the resulting current through the ion chamber and parasitic leakage current is measured at the second polarity. Since substantially no current flows through the ion chamber at the second polarity, the common mode parasitic leakage current contribution may be removed from the total current measurement by subtracting the current measured at the second polarity from the current measured at the first polarity, resulting in just the current through the ion chamber.

Abstract: A handheld stylus for use with a display device may include a handheld body, a tip movably coupled to the body, and at least one capacitive sensor configured to detect movements of the tip relative to the body. The at least one capacitive sensor may comprise at least one first conductive element secured to or integral with the body, and at least one second conductive element secured to or integral with the movable tip. The tip may be arranged such that the at least one first conductive element and the at least one second conductive element are spaced apart from each other. The at least one capacitive sensor may be configured to detect changes in respective distances between the at least one first conductive element and the at least one second conductive element caused by movements of the tip relative to the body.

Abstract: A guard ring is provided around each capacitive sensor plate and charged to substantially the same voltage as a voltage on the capacitive sensor plate. The guard ring reduces parasitic capacitances of the capacitive sensor plate caused by differences in voltage potentials between the capacitive sensor plate, and adjacent circuit conductors, ground planes and power planes. Two digital outputs and associated voltage divider resistors are used to drive the guard ring voltage to substantially the same voltage as the voltage on the capacitive sensor plate.

Abstract: An analog-to-digital (ADC) controller is used in combination with a digital processor of a microcontroller to control the operation of capacitance measurements using the capacitive voltage division (CVD) method. The ADC controller handles the CVD measurement process instead of the digital processor having to run additional program steps for controlling charging and discharging of a capacitive touch sensor and sample and hold capacitor, then coupling these two capacitors together, and measuring the resulting voltage charge thereon in determining the capacitance thereof. The ADC controller may be programmable and its programmable parameters stored in registers.

Abstract: An automated sequencer for a microcontroller is provided which makes a CVD conversion process a hardware function. The sequencer controls the charging/discharging of the sensor and ADC sample-and-hold capacitances, as well as the voltage division process. It also initiates the ADC conversion, with an optional second conversion for greater resolution, or a differential conversion.

Abstract: Capacitive proximity detection is provided by combining a delta-sigma modulator and a capacitive voltage divider circuit to create a high resolution capacitive-to-digital converter. Period and duty cycle counters provide duty cycle ratios from the delta-sigma modulator for comparison of changes in capacitance values of a capacitive sensor when an object is in proximity thereto.

Abstract: A door frame has a first electromagnetic coil and a door lock has a second electromagnetic coil with a door bolt electromagnetically coupling together the first and second electromagnetic coils, thereby forming a transformer. Power is transferred from the door frame to door lock through the transformer. Communications from the door frame to the door lock may be provided by modulating electromagnetic energy to the first electromagnetic coil and demodulating the modulated electromagnetic energy received at the second electromagnetic coil. Communications from the door lock to the door frame may be provided by varying a load on the second electromagnetic coil and detecting the load change at the first electromagnetic coil.