Patents Assigned to Virtual Machine Works, Inc.
  • Patent number: 5850537
    Abstract: 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.
    Type: Grant
    Filed: February 24, 1997
    Date of Patent: December 15, 1998
    Assignee: Virtual Machine Works, Inc.
    Inventors: Charles W. Selvidge, Anant Agarwal, Johnathan Babb, Matthew L. Dahl
  • Patent number: 5802348
    Abstract: A portion of a logic emulation system is configured to sample logic values from the portion of the emulation system that is used to emulate the user digital logic design. These sampled values are then multiplexed by the emulation system to a logic analysis device. Typically, this is a commercially-available logic analyzer. To achieve this functionality, the emulation system is provided with a clock signal that has a higher frequency than the emulation clock signal received from the target or user system. This high speed clock signal is provided to logic analyzer as a strobe signal and controls the transfer of words of logic values from the emulation system to the logic analyzer. As a result, the number of signals that the logic analyzer can effectively sample for a cycle of the emulation clock is increased.
    Type: Grant
    Filed: December 18, 1995
    Date of Patent: September 1, 1998
    Assignee: Virtual Machine Works, Inc.
    Inventors: Kem Stewart, Charles W. Selvidge, Kenneth Crouch, Marina Wong, Mark Seneski
  • Patent number: 5659716
    Abstract: 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.
    Type: Grant
    Filed: November 23, 1994
    Date of Patent: August 19, 1997
    Assignee: Virtual Machine Works, Inc.
    Inventors: Charles W. Selvidge, Anant Agarwal, Johnathan Babb, Matthew L. Dahl
  • Patent number: 5649176
    Abstract: 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.
    Type: Grant
    Filed: August 10, 1995
    Date of Patent: July 15, 1997
    Assignee: Virtual Machine Works, Inc.
    Inventors: Charles W. Selvidge, Matthew L. Dahl