Abstract: An infrared LED of an IrDA transceiver module is usable to transmit IrDA signals as well as RC control signals. When making an IrDA transmission, the IrDA LED is driven with a lower amount of current. When making an RC transmission, the IrDA LED is driven with an increased amount of current such that infrared emissions received by an RC receiver are of adequate power to be received as RC control signals. A current-limiting circuit allows more LED current to flow the longer current is allowed to flow through the IrDA LED. By controlling the durations of infrared bursts in the RC transmission, the average LED current during infrared bursts of RC transmissions is controlled. Using this technique allows the IrDA module to be used to transmit RC signals at different transmission power settings. To reduce power consumption, the minimum transmission power necessary to engage in RC communications is used.

Abstract: A compact, register-based, eight-bit virtual machine is realized on a resource-constrained device such as, for example, an IR remote control device. The IR remote control device includes a script interpreter, as well as loader API functionality and API functionality to support communication over a bidirectional link. The functionality of the remote control device is customized by loading either a machine code API routine and/or a script API routine onto the remote control device via the bidirectional link. A script is loaded via the bidirectional link and is stored in program memory. Once loaded, the script is interpreted by the virtual machine, thereby calling API functionalities provided, and thereby causing the remote control device to have a desired customized function. Providing the virtual machine on all the members of a family of remote control devices allows the same script to run on any remote control device of the family.

Abstract: A microcontroller determines the position of the rotor of a brushless, direct-current motor by determining the time of zero crossing of back electromotive force (EMF) emanating from the non-driven phase winding. The zero crossing point is determined by interpolating voltage differentials that are time stamped. Each voltage differential is the difference between the phase voltage of the phase winding and the motor neutral point voltage. The time of zero crossing is determined without using a comparator and without interrupting the processor at each zero crossing point. The processor interpolates the time of zero crossing independently of when the zero crossing point occurs. A hold signal conductor is connected both to a sample and hold circuit and to the load input lead of a time stamp register. The microcontroller simultaneously captures a phase voltage in the sample and hold circuit and a timer count in the time stamp register.

Abstract: Reading a value into a register, checking to see if the value is a NULL, and then jumping out of a loop if the value is a NULL is a common task that processors perform. To speed performance of such a task, a novel “blank bit” is added to the flag register of a processor. When a first instruction (arithmetic, logic or load) is executed, the instruction operands are checked to see if any is a NULL character value. Information on the result of the check is stored in the blank bit. Execution of a second instruction uses the information stored in the blank bit to determine whether or not a second operation (for example, a jump) will be performed. By using the first and second instructions in a loop, the number of instructions executed to check for NULLs at the end of strings and arrays is reduced.

Abstract: Reading a value into a register, checking to see if the value is a NULL, and then jumping out of a loop if the value is a NULL is a common task that processors perform. To speed performance of such a task, a novel “blank bit” is added to the flag register of a processor. When a first instruction (arithmetic, logic or load) is executed, the instruction operands are checked to see if any is a NULL character value. Information on the result of the check is stored in the blank bit. Execution of a second instruction uses the information stored in the blank bit to determine whether or not a second operation (for example, a jump) will be performed. By using the first and second instructions in a loop, the number of instructions executed to check for NULLs at the end of strings and arrays is reduced.

Abstract: A delay-locked loop (DLL) involves a pulse generating circuit that generates first and second pulses from an input clock signal. The second pulse is generated one clock signal period later than the first pulse. The first pulse is supplied to the input of a delay line. An edge of a delayed version of the first pulse as output from the delay line is phase-aligned with respect to a corresponding edge of the undelayed second pulse such that the DLL locks. The sending of pulses through the delay line of the DLL rather than clock signals having more edges per unit time helps reduce DLL aliasing problems and reduces the amount of switching in the delay line, thereby reducing power. consumption. A compact segmented delay line construction allows an input signal of arbitrary wave shape to be delayed by a fraction of the clock signal period.

Abstract: A portable electronic device with an IrDA transmitter LED is used to transmit both IrDA signals and remote control infrared signals. The device transmits remote control infrared signals with reduced power consumption. During a relatively longer remote control signal pulse, an inductor saturates and stores energy when a drive current flows from a power supply, through the inductor and then through the LED. An energy-transferring circuit transfers a portion of the energy stored in the inductor to the power supply. Energy is transferred when the drive current is cut and the voltage across the inductor surges, which causes an overflow current to flow through a diode in the energy-transferring circuit and to the power supply. The inductor is a planar coil of traces on a printed circuit board and therefore costs less to manufacture than does a toroidal coil of wires.

Abstract: A portable electronic device with an IrDA transmitter LED is used to transmit both IrDA signals and remote control infrared signals. The device transmits remote control infrared signals with reduced power consumption. During a relatively longer remote control signal pulse, an inductor saturates and stores energy when a drive current flows from a power supply, through the inductor and then through the LED. An energy-transferring circuit transfers a portion of the energy stored in the inductor to the power supply. Energy is transferred when the drive current is cut and the voltage across the inductor surges, which causes an overflow current to flow through a diode in the energy-transferring circuit and to the power supply. The inductor is a planar coil of traces on a printed circuit board and therefore costs less to manufacture than does a toroidal coil of wires.

Abstract: A low-power wireless network involves a plurality of RF-enabled fluorescent lamp starter units. In each of a plurality of intervals, a receiver of a starter unit operates in a receive mode during a beacon slot time, and for the majority of the rest of the interval operates in a low-power sleep mode. The starter unit wakes up and listens for a beacon each beacon slot time, regardless of whether a beacon is transmitted during that interval or not. A starter unit can be commanded to schedule a future action (for example, for a time between widely spaced synchronizing beacons) by making one of the beacons a scheduling beacon. The scheduling beacon includes a field that the starter unit uses to schedule the future action. If the scheduled action is to be canceled before the next widely spaced synchronizing beacon, then an action-canceling beacon is communicated in the next interval.

Abstract: A wall switch motion sensor detects motion using a lens and an infrared detector, and in response performs a function (for example, turns on a light). The motion sensor is also adapted to respond to IR remote control signals of the type customarily used to control electronic consumer devices in the home. In one example, a user uses an ordinary remote control device to transmit a sequence of IR control signals and dead times toward the motion sensor. The detector in the motion sensor detects each IR control signal as an increased amount of IR energy, whereas it detects a dead time as a period of less IR energy. If the periodicity of the sequence is appropriate, then the wall switch motion sensor determines that the sequence is an instruction. In one example, the instruction is to turn on/off the light controlled by the wall switch motion sensor.

Abstract: An infrared LED of an IrDA transceiver module is usable to transmit IrDA signals as well as RC control signals. When making an IrDA transmission, the IrDA LED is driven with a lower amount of current. When making an RC transmission, the IrDA LED is driven with an increased amount of current such that infrared emissions received by an RC receiver are of adequate power to be received as RC control signals. A current-limiting circuit allows more LED current to flow the longer current is allowed to flow through the IrDA LED. By controlling the durations of infrared bursts in the RC transmission, the average LED current during infrared bursts of RC transmissions is controlled. Using this technique allows the IrDA module to be used to transmit RC signals at different transmission power settings. To reduce power consumption, the minimum transmission power necessary to engage in RC communications is used.

Abstract: A microcontroller determines the position of the rotor of a brushless, direct-current motor by determining the time of zero crossing of back electromotive force (EMF) emanating from the non-driven phase winding. The zero crossing point is determined by interpolating voltage differentials that are time stamped. Each voltage differential is the difference between the phase voltage of the phase winding and the motor neutral point voltage. The time of zero crossing is determined without using a comparator and without interrupting the processor at each zero crossing point. The processor interpolates the time of zero crossing independently of when the zero crossing point occurs. A hold signal conductor is connected both to a sample and hold circuit and to the load input lead of a time stamp register. The microcontroller simultaneously captures a phase voltage in the sample and hold circuit and a timer count in the time stamp register.

Abstract: A microcontroller determines the position of the rotor of a brushless, direct-current motor by determining the time of zero crossing of back electromotive force (EMF) emanating from the non-driven phase winding. The zero crossing point is determined by interpolating voltage differentials that are time stamped. Each voltage differential is the difference between the phase voltage of the phase winding and the motor neutral point voltage. The time of zero crossing is determined without using a comparator and without interrupting the processor at each zero crossing point. The processor interpolates the time of zero crossing independently of when the zero crossing point occurs. A hold signal conductor is connected both to a sample and hold circuit and to the load input lead of a time stamp register. The microcontroller simultaneously captures a phase voltage in the sample and hold circuit and a timer count in the time stamp register.

Abstract: A F/2F waveform generator has a comparator and an analog multiplexer. In a low-cost magnetic card reader application, a magnetic track signal is amplified, filtered, and compared with a threshold signal to create a digital signal output. The analog multiplexer detects changes in state of the digital signal. When a change of state is detected, the analog multiplexer switches among dynamically tunable threshold signals. The selected threshold signal is used for comparison with the magnetic track signal. Switching level detection enables accurate F/2F waveform generation from relatively noisy magnetic track signals, thus improving the robustness of magnetic card readers. The analog implementation eliminates the need for expensive A/D conversion and processing and the design can be readily implemented in a very compact and low-cost package.

Abstract: A microcontroller integrated circuit includes an open-loop transimpedance amplifier (OLTA). An input lead of the OLTA is a terminal of the microcontroller. The cathode of a photodiode is connected to VDD and the anode is connected to the terminal. The OLTA maintains the photodiode in a strongly reverse-biased condition, thereby keeping diode capacitance low and facilitating rapid circuit response. The input of the OLTA involves a diode-connected field effect transistor that provides a low impedance. This low impedance decreases as the diode current increases, thus providing effective clamping of the voltage on the terminal. By this clamping, the amount of photodiode capacitance discharging necessary when transitioning from a high input current condition to a low input current condition is reduced, thereby further improving amplifier response time. The OLTA is small and consumes less than thirty microamperes and functions to mirror photodiode current and compare to a predetermined level.

Abstract: A microcontroller integrated circuit includes an open-loop transimpedance amplifier (OLTA). An input lead of the OLTA is a terminal of the microcontroller. The cathode of a photodiode is connected to VDD and the anode is connected to the terminal. The OLTA maintains the photodiode in a strongly reverse-biased condition, thereby keeping diode capacitance low and facilitating rapid circuit response. The input of the OLTA involves a diode-connected field effect transistor that provides a low impedance. This low impedance decreases as the diode current increases, thus providing effective clamping of the voltage on the terminal. By this clamping, the amount of photodiode capacitance discharging necessary when transitioning from a high input current condition to a low input current condition is reduced, thereby further improving amplifier response time. The OLTA is small and consumes less than thirty microamperes and functions to mirror photodiode current and compare to a predetermined level.

Abstract: A method of fabricating a high-performance capacitor that may be incorporated into a standard CMOS fabrication process suitable for submicron devices is described. The parameters used in the standard CMOS process may be maintained, particularly for the definition and etch of the lower electrode layer. To reduce variation in critical dimension width, an Anti-Reflective Layer (ARL) is used, such as a Plasma Enhanced chemical vapor deposition Anti-Reflective Layer (PEARL) or other Anti-Reflective Coatings (ARCS), such as a conductive film like TiN. This ARL formation occurs after the capacitor specific process steps, but prior to the masking used for defining the lower electrodes. A Rapid Thermal Oxidation (RTO) is performed subsequent to removing the unwanted capacitor dielectric layer from the transistor poly outside of the capacitor regions, but prior to the PEARL deposition.

Abstract: A programmable spread spectrum clock generator (SSCG) reduces electromagnetic interference by spreading the frequency bandwidth of an output signal. The rate at which the frequency of the output signal changes, as well as other aspects of the output signal, are software programmable. The programmable SSCG receives a periodic signal whose cycles have substantially identical periods and outputs the output signal whose cycles have periods that vary smoothly over a plurality of cycles of the periodic signal. The programmable SSCG generates a control signal using the periodic signal. The programmable SSCG includes a variable delay element that generates the output signal by delaying the periods of the periodic signal based on the magnitude of the control signal. The output signal is generated without using a phase locked loop. Moreover, successive cycles of the output signal rarely have identical periods.

Abstract: A F/2F waveform generator has a comparator and an analog multiplexer. In a low-cost magnetic card reader application, a magnetic track signal is amplified, filtered, and compared with a threshold signal to create a digital signal output. The analog multiplexer detects changes in state of the digital signal. When a change of state is detected, the analog multiplexer switches among dynamically tunable threshold signals. The selected threshold signal is used for comparison with the magnetic track signal. Switching level detection enables accurate F/2F waveform generation from relatively noisy magnetic track signals, thus improving the robustness of magnetic card readers. The analog implementation eliminates the need for expensive A/D conversion and processing and the design can be readily implemented in a very compact and low-cost package.

Abstract: A microcontroller integrated circuit includes an open-loop transimpedance amplifier (OLTA). An input lead of the OLTA is a terminal of the microcontroller. The cathode of a photodiode is connected to VDD and the anode is connected to the terminal. The OLTA maintains the photodiode in a strongly reverse-biased condition, thereby keeping diode capacitance low and facilitating rapid circuit response. The input of the OLTA involves a diode-connected field effect transistor that provides a low impedance. This low impedance decreases as the diode current increases, thus providing effective clamping of the voltage on the terminal. By this clamping, the amount of photodiode capacitance discharging necessary when transitioning from a high input current condition to a low input current condition is reduced, thereby further improving amplifier response time. The OLTA is small and consumes less than thirty microamperes and functions to mirror photodiode current and compare to a predetermined level.