Virtual Machine Works, Inc.

Mentor Graphics Corporation

Ikos Systems, Inc.

Matthew L Dahl

Charles W Selvidge

Anant Agarwal

Johnathan Babb

Jonathan William Babb

Kenneth W Crouch

Vipul Kulshrestha

Laurent Vuillemin

Anant Argarwal

Michael Donald Noakes

Ansuman Prusty

Various aspects of the present disclosed technology relate to techniques for selective conditional stall for speeding up hardware-based circuit verification. A path-breaking circuit device is inserted into a location of a design path configured to generate a stall signal indicating whether a change of signal between a pair of neighboring clock cycles of a clock signal is detected at the location. The stall signal is used to directly or indirectly suppress, when the change of signal between the pair of neighboring clock cycles is detected, the next state updating for state element models in the hardware model of circuit design. The design path is usually the critical design path. The insertion location is usually selected to be a location where the signal does not change frequently.

Selective conditional stall for hardware-based circuit design verification

A method of configuring a configurable logic system, including a single or multi-FPGA network, is disclosed in which an internal clock signal is defined that has a higher frequency than timing signals the system receives from the environment in which it is operating. The frequency can be at least ten times higher than a frequency of the environmental timing signals. The logic system is configured to have a controller that coordinates operation of its logic operation in response to the internal clock signal and environmental timing signals. Specifically, the controller is a finite state machine that provides control signals to sequential logic elements such as flip-flops. The logic elements are clocked by the internal clock signal. In the past, emulation or simulation devices, for example, operated in response to timing signals from the environment. A new internal clock signal, invisible to the environment, rather than the timing signals is used to control the internal operations of the devices. Additionally, a specific set of transformations are disclosed that enable the conversion of a digital circuit design with an arbitrary clocking methodology into a single clock synchronous circuit.

Transition analysis and circuit resynthesis method and device for

A configurable logic system programmed to model a logic design comprises an array of programmable logic modules each configured to perform a partition block of the logic design and a module interconnect providing connections between the modules. The interconnect enables transmission of global links between the partition blocks of the modules. The modules time division multiplex the global links, with a destination module then demultiplexing the global links allowing the links to pass through to another FPGA. The modules are configured to transmit individual ones of the global links at time intervals determined in response to a ready time of the individual links. The ready times of individual global links are determined in response to receipt of parent global links and signal propagation delays across the modules. A parent of a particular global link is a link that affects a logic value of the global link. The present invention allows computation and communication simultaneously. Previously, the calculations and communications were divided into discrete phases within each emulation clock period.

Pipe lined static router and scheduler for configurable logic system

A programmable logic circuit includes a programmable logic array which generates a plurality of output signals for output from a single port on the programmable logic circuit, and which processes a plurality of input signals received from a single port on the programmable logic circuit. The programmable logic circuit also includes multiplexing means for receiving the plurality of output signals generated by the programmable logic array and for multiplexing the plurality of output signals. An output port outputs, from the programmable logic circuit, the multiplexed plurality of output signals generated by the programmable logic array. An input port receives a multiplexed plurality of input signals, and a demultiplexing means demultiplexes the multiplexed plurality of input signals and configurably communicates the demultiplexed plurality of input signals to the programmable logic array. This demultiplexing means and the multiplexing means are each operable at a clock speed which is different from a clock speed of the programmable logic array.

Programmable multiplexing input/output port

Pipe-lined static router and scheduler for configurable logic system

Growing community of inventors

Cambridge, MA, United States of America

Matthew L Dahl