Abstract: A multichannel numerically controlled oscillator is provided. The multichannel numerically controlled oscillator has a dual port memory. An output function generation lookup table in the dual port memory is used to generate output functions for the numerically controlled oscillator. A first channel of output is generated based on a first address signal that is presented on a first port of the dual port memory. A second channel of output is generated based on a second address signal that is presented on a second port of the dual port memory. First and second phase accumulators may be used to produce the address signals for the first and second ports of the dual port memory, respectively. The phase accumulators may each contain a register, an adder, and a feedback path. The registers in the phase accumulators and the dual port memory may handle signals at the clock rate of the output channels.

Abstract: A system is provided that uses identity-based encryption to support secure communications between senders and recipients over a communications network. Private key generators are used to provide public parameter information. Senders encrypt messages for recipients using public keys based on recipient identities and using the public parameter information as inputs to an identity-based encryption algorithm. Recipients use private keys to decrypt the messages. There may be multiple private key generators in the system and a given recipient may have multiple private keys. Senders can include private key identifying information in the messages they send to recipients. The private key identifying information may be used by the recipients to determine which of their private keys to use in decrypting a message. Recipients may obtain the correct private key to use to decrypt a message from a local database of private keys or from an appropriate private key server.

Abstract: Computer aided design tools are provided that assist circuit designers in optimizing circuit performance. A circuit designer who is designing an integrated circuit may supply circuit design data and constraint data. Computer aided design tools may process the data to produce output data. The output data may include information on an implementation of the circuit design in a given type of integrated circuit device and may include report data on how the implementation of the circuit design is expected to perform. An optimization assistance tool analyzes the design and constraint data and the report data to identify potential problem areas. Recommendations may be provided to the circuit designer on how to address potential problems. Selectable options are displayed for the circuit designer. By selecting an appropriate option, the circuit designer can automatically launch a tool to make recommended settings adjustments.

Abstract: A digital decoder is provided that produces true and complementary output signals. The digital decoder may be formed from n-channel and p-channel metal-oxide-semiconductor transistors. The digital decoder produces four true outputs and four complementary outputs from two inputs. A first of the true outputs and a first of the complementary outputs are provided using a NOR gate and an inverter. A NAND gate and an inverter are used to provide a second of the true outputs and a second of the complementary outputs. Third and fourth complementary outputs are produced using first and second logic circuits. The first and second logic circuits are powered using only a positive power supply voltage. Third and fourth true outputs are produced using third and fourth logic circuits. The third and fourth logic circuits are powered using only a ground power supply voltage. The logic circuits each include an n-channel and p-channel transistor pair.

Abstract: Methods and apparatus for designing and producing programmable logic devices are provided. A logic design system may be used to analyze various implementations of a desired logic design for a programmable logic device integrated circuit. The logic design system may be used to produce configuration data for the programmable logic device in accordance with an implementation that minimizes power consumption by the programmable logic device. The programmable logic device contains logic blocks that are used to implement the desired logic design and logic blocks that are unused. Dynamic power consumption can be minimized by identifying which configuration data settings reduce the amount of signal toggling in the unused logic blocks and routing, and by minimizing the capacitance of resources that do toggle. Clock tree power consumption can be reduced by evaluating multiple potential logic design implementations using a strictly concave cost function.

Abstract: Adjustable transceiver circuitry is provided for programmable integrated circuits. The transceiver circuitry has a dynamic phase alignment circuit that can be used for aligning clock and data signals. The transceiver circuitry supports a phase-locked-loop source synchronous mode that can be used to receive data from transmitting integrated circuits that are clocked with a common clock. Each transmitting integrated circuit transmits a clock and associated data signals over a bus. The transceiver circuitry uses a master-slave architecture. A master dynamic phase alignment circuit in each transceiver receives the clock for that bus and selects a corresponding optimal clock phase to use in receiving input data for the bus from a multiphase clock. The master dynamic phase alignment circuit in each transceiver distributes the optimal clock phase to associated slave dynamic phase alignment circuits. Only a single phase-locked loop circuit is need to generate the multiphase clock.

Abstract: A handheld electronic device is provided that contains wireless communications circuitry. The wireless communications circuitry may include antennas. An antenna in the handheld electronic device may have a ground plane element. A slot antenna resonating element may be formed from an opening in the ground plane element. A near-field-coupled antenna resonating element may be electromagnetically coupled to the slot antenna resonating element through electromagnetic near-field coupling. A transmission line may directly feed the slot antenna resonating element. The transmission line may indirectly feed the near-field-coupled antenna resonating element through the slot antenna resonating element. The slot antenna resonating element may have one or more associated resonant frequencies and the near-field-coupled antenna resonating element may have one or more associated resonant frequencies. The antenna may be configured to cover one or more distinct communications bands.

Abstract: Methods and apparatus for testing integrated circuits are provided. Integrated circuits sometimes contain repeating blocks of identical circuitry. Each identical circuit block contains scan chain registers that can be used to support testing. Each circuit block also has associated inputs and outputs. The inputs and outputs of the circuit blocks serve to interconnect each block to its neighboring blocks. An integrated circuit to be tested is described by a circuit netlist. The circuit netlist is processed to identify identical netlist modules. The repeating netlist modules correspond to the identical circuit blocks on the integrated circuit. By processing a given instance of a repeating netlist module, block-level test data can be generated. Global test data suitable for testing the entire integrated circuit can be generated from the block-level test data.

Abstract: Systems and methods for managing email are provided. Some of the email may be encrypted using identity-based-encryption (IBE) techniques. When an incoming IBE-encrypted message for a recipient in an organization is received by a gateway at the organization, the gateway may request an IBE private key from an IBE private key generator. The IBE private key generator may generate the requested IBE private key for the gateway. The gateway may use an IBE decryption engine to decrypt the incoming message. The decrypted message can be scanned for viruses and spam and delivered to the recipient. Outgoing email messages can also be processed. If indicated by message attributes or information provided by a message sender, an outgoing message can be encrypted using an IBE encryption engine and the IBE public key of a desired recipient.

Abstract: A logic design system is provided for designing programmable logic device integrated circuits with minimized simultaneous switching noise. The logic design system identifies input-output drivers that are associated with simultaneous switching noise groups by examining a netlist for a circuit design for a programmable logic device. Simultaneous switching noise is minimized by making adjustments to programmable operating parameters for the input-output drivers. The logic design system may make adjustments such as adjustments to programmable drive strengths, programmable slew rates, and programmable on-chip termination resistances. During place and route operations, the logic design system makes placement decisions that help to minimize simultaneous switching noise.

Abstract: An integrated circuit is provided with body bias generation circuitry. The body bias generation circuitry generates a body bias signal that is provided to transistors on a body bias path. The body bias generation circuitry contains an active latch-up prevention circuit that clamps the body bias path at a safe voltage when potential latch-up conditions are detected. The level of body bias signal that is generated by the body bias circuitry is adjustable. The body bias generation circuitry regulates the body bias voltage on the body bias path using a p-channel control transistor. An isolation transistor is coupled between the p-channel control transistor and the body bias path. During potential latch-up conditions, the isolation transistor is turned off to isolate the body bias path from ground. Control circuitry adjusts a body bias voltage that is applied to body terminals in the p-channel control transistor and isolation transistor.

Abstract: A verifiable duplex multiplier circuit is provided. In one mode, the circuitry of the duplex multiplier functions as an N-bit×N-bit multiplier. In another mode, the circuitry of the duplex multiplier operates as dual N/2-bit×N/2-bit multipliers. Because the same circuitry can be used to serve as both an N×N multiplier and as dual N/2×N/2 multipliers, integrated circuit resources are conserved. The duplex multiplier circuitry uses an architecture that can be automatically synthesized using a logic synthesis tool. Verification operations can be performed using logic-equivalency error checking tools. Exhaustive verification is possible using this approach, even when relatively large duplex multipliers (e.g., duplex multipliers with N values of 16 or more) are used.

Abstract: A logic design system is provided for designing programmable logic device integrated circuits with minimized predriver power consumption. The logic design system identifies predriver circuits that can operate satisfactorily at reduced predriver power supply levels. One or more reduced predriver power supply levels for powering the predriver circuits are identified by the logic design system. The predriver power supply levels that are identified can be different than a maximum allowable power supply voltage used for powering input-output circuitry on the programmable logic device integrated circuit. There may be multiple blocks of predriver circuitry, each of which is powered using a potentially different predriver power supply voltage. The logic design system uses on-screen options to accept user-supplied settings related to minimizing predriver power consumption.

Abstract: Programmable logic device integrated circuits with differential communications circuitry are provided in which the differential communications circuitry is used to support programming, testing, and user mode operations. Programming operations may be performed on a programmable logic device integrated circuit by receiving configuration data with the differential communications circuitry and storing the received configuration data in nonvolatile memory. The nonvolatile memory may be located in an external integrated circuit such as a configuration device or may be part of the programmable logic device integrated circuit. The stored configuration data may be loaded into configuration memory in the programmable logic device to program the device to perform a desired custom logic function. The differential communications circuitry may be used to handle boundary scan tests and programmable scan chain tests. During user mode operations the differential communications circuitry carries user data traffic.

Abstract: An integrated circuit such as a programmable logic device integrated circuit is provided that contains body-biased metal-oxide-semiconductor transistors and latch-up prevention circuitry to prevent latch-up from occurring in metal-oxide-semiconductor transistors. Body bias signals can be received from an external source or generated internally. Body bias paths are used to distribute the body bias signals to the body terminals of the metal-oxide-semiconductor transistors. The latch-up prevention circuitry may include active n-channel and p-channel metal-oxide-semiconductor transistor latch-up prevention circuitry. The latch-up prevention circuitry monitors the states of power supply signals to determine whether a potential latch-up condition is present.

Abstract: An integrated circuit is provided that contain n-channel and p-channel metal-oxide-semiconductor transistors having body terminals. Adjustable transistor body bias circuitry is provided on the integrated circuit that provides body bias voltages to the body terminals to minimize power consumption. The adjustable body bias circuitry can be controlled using programmable elements on the integrated circuit that are loaded with configuration data. The integrated circuit may be a programmable logic device integrated circuit containing programmable logic. The adjustable body bias circuitry can produce an adjustable negative body bias voltage for biasing n-channel metal-oxide-semiconductor transistors. The adjustable body bias circuitry contains a bandgap reference circuit, a charge pump circuit, and an adjustable voltage regulator.

Abstract: Methods and apparatus for transferring patients are provided. A patient transfer device may have a wheeled base and a lateral transfer structure. A patient may lie supine on a patient support structure on top of a transfer sheet. Airbags may be adjusted beneath the transfer sheet to form channels. To transfer the patient from the patient support structure to the wheeled base, the lateral transfer structure is extended into the channels beneath the patient. A stretcher frame is formed from the extended lateral transfer structure. A stretcher that supports the patient is formed by attaching the transfer sheet to the stretcher frame. After the stretcher has been formed, the extended portions of the lateral transfer structure may be retracted to move the stretcher and patient on top of the wheeled base. The patient transfer device may be adjusted to allow the patient to assume a sitting position during transit.

Abstract: Integrated circuits such as programmable logic device integrated circuits are provided that have memory arrays. The memory arrays can be tested using configurable built in self test circuitry. The built in self test circuitry may have test control register circuitry and configurable state machine logic. The state machine logic may perform at-speed tests on a memory array and may provide test results to external equipment for analysis. A tester may be used to provide test control settings to the test control register circuitry. The test control settings may include march element settings for a march sequence. During testing, the configurable state machine logic may use the march element settings to generate march sequences. March sequences that have been generated in this way may be used in testing the memory array.

Abstract: Dual port memory array circuitry is provided that includes bit line voltage clamping circuitry. The clamping circuitry contains control transistors that are used to enable and disable the clamping circuitry. The clamping circuitry also contains voltage regulator transistors and feedback paths. When a write operation is performed on one port of the dual port memory array while a read operation is being performed on the other port of the dual port memory array, the bit line voltage clamping circuitry prevents the voltages on the read port bit lines from dropping too low. This allows the write operation to be performed rapidly, even if the memory cell being written to has been adversely affected by variations due to process, voltage, and temperature.

Abstract: Integrated circuits such as programmable logic device integrated circuits are provided with adjustable configuration random-access-memory cell power supply circuitry. The adjustable configuration random-access-memory cell power supply circuitry powers configuration random-access-memory cells on an integrated circuit. During operation of the integrated circuit, the configuration random-access-memory cells provide static output signals that turn on and off associated pass transistors. The adjustable power supply circuitry can be configured to produce different power supply voltages on different portions of an integrated circuit. The different power supply voltages accommodate circuit design constraints while minimizing power consumption due to pass transistor leakage.