Xilinx, Inc.

Benjamin S Devlin

Ilya K Ganusov

Brian C Gaide

Rafael C Camarota

Jindrich Zejda

Henri Fraisse

Santosh Kumar Sood

Satish B Sivaswamy

Walter A Manaker, Jr

Atul Srinivasan

Aspects of various embodiments of the present disclosure are directed to methods and circuits preventing hold violations in clock synchronized circuits. In an example implementation, a circuit includes a logic circuit having a set of inputs. Signal propagation time on a signal path to at least one of the set of inputs presents a hold violation. The circuit includes first and second level-sensitive latches. The first level-sensitive latch has an output connected to the one of the plurality of inputs. The second level-sensitive latch has an input connected to an output of the logic circuit. A latch control circuit is configured to remove the hold violation on the input by providing a pulsed clock signal to a clock input of the second level-sensitive latch and an inversion of the pulsed clock signal to a clock input of the first level-sensitive latch.

Methods and circuits for preventing hold violations

A circuit for implementing a scan chain in programmable resources of an integrated circuit is described. The circuit comprises a programmable element configured to receive an input signal and generate an output signal based upon the input signal; a selection circuit configured to receive the output signal generated by the programmable element at a first input and to receive a scan chain input signal at a second input, wherein the selection circuit generates a selected output signal in response to a selection circuit control signal; and a register configured to receive the selected output signal of the selection circuit.

Circuit for and method of implementing a scan chain in programmable resources of an integrated circuit

A register circuit includes a first pulse-latch circuit configured to store data from a first input node. A multiplexer circuit is configured to select between an output of the first pulse-latch circuit and a second input node. A second pulse-latch circuit is configured to store data provided by the multiplexer circuit. A control circuit is configured to switch, in response to a configuration signal, the register circuit between a flip-flop mode and a dual-latch mode.

Multimode registers with pulse latches

A circuit for reducing power consumed by routing clock signals in an integrated circuit is described. The circuit comprises a clock routing network comprising a clock row coupled to receive an input clock signal having a first clock frequency and a plurality of clock branches coupled to the clock row; and a plurality of circuit blocks coupled to the plurality of clock branches, each circuit block having a clock conversion circuit and a register; wherein the clock conversion circuit is programmable to generate clock pulses of an internal clock signal, coupled to the register, having a second frequency that is greater than the first frequency. A method of reducing power consumed by routing clock signals in an integrated circuit is also disclosed.

Circuits for and methods of reducing power consumed by routing clock signals in an integrated

Aspects of various embodiments of the present disclosure are directed to methods and circuits for preventing hold time violations in clock synchronized circuits. In an example implementation, a circuit includes at least a first flip-flop, a second flip-flop, and a level-sensitive latch connected in a signal path from the first flip-flop to the second flip-flop. A clock node of the first flip-flop is connected to receive a first clock signal and a clock node of the second flip-flop is connected to receive a second clock signal. The propagation delay from the first flip-flop through the level-sensitive latch to the second flip-flop is smaller than the skew between the first clock and the second clock, thereby presenting a hold time violation. A level-sensitive latch control circuit is configured to prevent the hold time violation by providing a pulsed clock signal to a clock node of the one level-sensitive latch circuit.

Methods and circuits for preventing hold time violations

A method, non-transitory computer readable medium and circuit for detecting and correcting errors in a communication channel are disclosed. The circuit includes error monitoring logic for monitoring the communication channel in real time for a performance metric, a fixed-operating point encoder/decoder coupled to the error monitoring logic for generating a bit stream containing redundant data used for the detecting and correcting, a reconfigurable controller coupled to the fixed-operating point encoder/decoder, wherein a configuration of the reconfigurable controller determines an amount of the redundant data contained in the bit stream, and a data structure implemented in a logic fabric of the circuit and coupled to the error monitoring logic, for generating the configuration of the reconfigurable controller responsive to a value of the performance metric controller.

Method and apparatus for detecting and correcting errors in a communication channel

Approaches for processing a circuit design include determining pin slack values for pins of the circuit elements in the circuit design. A processor selects a subset of endpoints based on pin slack values of the endpoints being in a critical slack range and determines startpoints of the circuit design that are in respective critical fanin cones. For each endpoint of the subset, the processor determines an arrival time from each startpoint in the respective critical fanin cone and determines for each startpoint-endpoint pair, a respective set of constraint values as a function of the respective arrival time from the startpoint. The processor generates a graph in the memory circuit from the startpoint-endpoint pairs. First nodes in the graph represent the startpoints and second nodes in the graph represent the endpoints, and values in the respective set of constraint values are associated with edges that connect the nodes.

Representation of complex timing characteristics of startpoint-endpoint pairs in a circuit design

A device includes a multiplexer circuit with a plurality of input circuits. Each input circuit is connected to a respective input node and a shared output node. The input circuits are configured to pass, in response to a respective control signal, a signal between the respective input and shared output node. An output circuit is configured to store data from the shared output node in a latch mode and to act as a buffer in a pass-through mode. A control circuit is configured to switch, in response to a configuration signal, the output circuit between the latch mode and the pass-through mode.

Multimode multiplexer-based circuit

A circuit for reducing duty-cycle distortion in an integrated circuit implementing dual-edge clocking is described. The circuit also comprises a plurality of circuit elements that enable the routing of data generated at outputs of the circuit elements; a plurality of register circuits that store data at outputs of the plurality of circuit elements; a clock circuit routing a clock signal to clock inputs of the plurality of register circuits; and a pulsed-controlled register circuit coupled to an output of a circuit element and generating a pulsed output coupled to a clock input of a register of the pulse-controlled register circuit; wherein the pulsed output is coupled to the clock input of the register to enable the pulse-controlled register circuit to store data at a time that is different than an edge of the clock signal. A method of reducing duty-cycle distortion in an integrated circuit implementing dual-edge clocking is also described.

Circuits for and methods of reducing duty-cycle distortion in an integrated circuit implementing dual-edge clocking

Methods and apparatus for generating multiple phase-shifted clock signals from a base clock signal using programmable delays at the leaf level in a clock distribution network are described. One example method for generating and distributing multiple phase-shifted clock signals in a programmable integrated circuit (IC) generally includes generating a base clock signal, routing the base clock signal through a clock distribution network in the programmable IC to a leaf node, and applying one or more programmable delays to the base clock signal received from the leaf node to generate the multiple phase-shifted clock signals.

Leaf-level generation of phase-shifted clocks using programmable clock delays

In an example implementation, a circuit includes first and second latch circuits. A circuit coupled to the first and second latch circuits is configured to provide a first clock signal to the clock input node of the second latch circuit and provide a second clock signal that is an inversion of the first clock signal to the clock input node of the first latch circuit. The circuit includes a first multiplexer having a first input node coupled to a data output node of the first latch circuit, a second input node coupled to a data input node of the first latch circuit, and an output node coupled to a data input node of the second latch circuit. The circuit also includes a second multiplexer having a first input node coupled to the data output node of the first latch circuit and a second input node coupled to a data output node of the second latch circuit.

Configurable latch circuit

An integrated circuit includes: a voltage rail; voltage control circuitry coupled to the voltage rail; and a circuit block coupled to the voltage control circuitry; wherein the voltage control circuitry is selectively configurable to operate the circuit block in at least a first mode of operation and a second mode of operation; wherein in the first mode of operation, the circuit block receives a voltage that is substantially the same as a voltage of the voltage rail; and wherein in the second mode of operation, the circuit block receives a voltage that is less than the voltage of the voltage rail by a threshold voltage.

Programmable power reduction technique using transistor threshold drops

A programmable delay circuit block includes an input stage having a cascade input and a clock input, wherein the input stage passes a signal received at the cascade input or a signal received at the clock input. The programmable delay circuit block further may include a delay block configured to generate a delayed signal by applying a selected amount of delay to the signal passed from the input stage and a pulse generator configured to generate a pulse signal having a pulse width that depends upon the amount of delay. The programmable delay circuit block also includes an output stage having a cascade output and a clock output. The output stage is configured to pass an inverted version of the pulse signal or the delayed signal from the cascade output and pass the signal received at the clock input, the inverted version of the pulse signal, or the delayed signal from the clock output.

Growing community of inventors

San Francisco, CA, United States of America

Benjamin S Devlin