Patents by Inventor Stephen M. Douglass

Stephen M. Douglass has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7539848
    Abstract: A system is disclosed comprising a logic circuit in an integrated circuit device, wherein the logic circuit comprises a logic fabric that includes a plurality of configurable logic blocks, switching blocks, and input/output blocks, wherein the logic fabric is configured according to configuration data provided to the integrated circuit device from an external memory and at least a portion of the logic fabric is configured as a configured processor to perform a first fixed logic function according to the configuration data. A fixed logic processor, a first auxiliary processing interface, a second fixed logic processor, a second auxiliary processing interface enable communication with the configured processor, wherein the configured processor remains configured to enable both the fixed logic processor and the second fixed logic processor to access the configured processor to perform the fixed logic function.
    Type: Grant
    Filed: September 30, 2005
    Date of Patent: May 26, 2009
    Assignee: Xilinx, Inc.
    Inventors: Stephen M. Douglass, Ahmad R. Ansari
  • Patent number: 7420392
    Abstract: Interconnecting logic provides connectivity of an embedded fixed logic circuit, or circuits, with programmable logic fabric of a programmable gate array such that the fixed logic circuit functions as an extension of the programmable logic fabric. The interconnecting logic includes interconnecting tiles and may further include interfacing logic. The interconnecting tiles provide selective connectivity between inputs and/or outputs of the fixed logic circuit and interconnect of the programmable logic fabric. The interfacing logic, when included, provides logic circuitry that conditions data transfers between the fixed logic circuit and the programmable logic fabric. In one operation, the programmable logic fabric is configured prior to the startup/boot sequence of the fixed logic circuit. In another operation, the fixed logic circuit is started up and is employed to configure the programmable logic fabric.
    Type: Grant
    Filed: July 23, 2004
    Date of Patent: September 2, 2008
    Assignee: XILINX, Inc.
    Inventors: David P. Schultz, Stephen M. Douglass, Steven P. Young, Nigel G. Herron, Mehul R. Vashi, Jane W. Sowards
  • Patent number: 7406670
    Abstract: Method and apparatus for generating a test program for an integrated circuit having an embedded processor. One embodiment has a system which includes an embedded microprocessor; a plurality of assembly language instructions stored in a memory, where the assembly language instructions substantially exercise a critical path or a path closest to the critical path in the embedded microprocessor; and programmable test circuitry having a programmable clock circuit for providing a multiplied clock signal to the embedded microprocessor in order to execute the assembly language instructions.
    Type: Grant
    Filed: August 1, 2007
    Date of Patent: July 29, 2008
    Assignee: Xilinx, Inc.
    Inventors: Ahmad R. Ansari, Mehul R. Vashi, Nigel G. Herron, Stephen M. Douglass
  • Patent number: 7269805
    Abstract: Method and apparatus for generating a test program for an integrated circuit having an embedded processor. One embodiment has a system which includes an embedded microprocessor; a plurality of assembly language instructions stored in a memory, where the assembly language instructions substantially exercise a critical path or a path closest to the critical path in the embedded microprocessor; and programmable test circuitry having a programmable clock circuit for providing a multiplied clock signal to the embedded microprocessor in order to execute the assembly language instructions.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: September 11, 2007
    Assignee: Xilinx, Inc.
    Inventors: Ahmad R. Ansari, Mehul R. Vashi, Nigel G. Herron, Stephen M. Douglass
  • Patent number: 7231621
    Abstract: Method and apparatus for generating a test program for a programmable logic device having an embedded processor. Predetermined code is obtained to exercise at least one speed limiting path identified. To the predetermined code is added wrapper code to provide the test program, the wrapper code in part for loading the predetermined code into cache of the embedded processor for testing the at least one speed limiting path of the embedded processor identified.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: June 12, 2007
    Assignees: Xilinx, Inc., International Business Machines
    Inventors: Nigel G. Herron, Ahmad R. Ansari, Stephen M. Douglass, Anthony Correale, Jr., Leslie M. DeBruyne
  • Patent number: 7194600
    Abstract: A method and apparatus for processing data within a programmable gate array comprise a first fixed logic processor and a second fixed logic processor that are embedded within the programmable gate array and detect a custom operation code. The processing continues when a fixed logic processor provides an indication of the custom operational code to the programmable gate array. The processing continues by having at least a portion of the programmable gate array, which is configured as a dedicated processor, performing a fixed logic routine upon receiving the indication from the fixed logic processor.
    Type: Grant
    Filed: February 17, 2005
    Date of Patent: March 20, 2007
    Assignee: Xilinx, Inc.
    Inventors: Stephen M. Douglass, Ahmad R. Ansari
  • Patent number: 6961919
    Abstract: A method for designing an integrated circuit having both fixed logic and programmable logic components. An intended set of applications for the integrated circuit is first identified. In addition, for each of the intended set of applications, the logic requirements are identified. An approximate number of configurable logic blocks and at least one fixed logic circuit are selected that, when combined to operate cooperatively, meet a substantial portion of the logic requirements and the logic functions of the intended set of applications. The method also involves designing the integrated circuit with the approximate number of configurable logic blocks arranged and interconnected to form a fabric that surrounds an opening, and inserting the at least one fixed logic circuit into the opening in the fabric. In addition, the method involves adding logic to the integrated circuit that interfaces the at least one fixed logic circuit to the fabric and input/output circuitry.
    Type: Grant
    Filed: March 4, 2002
    Date of Patent: November 1, 2005
    Assignee: Xilinx, Inc.
    Inventor: Stephen M. Douglass
  • Patent number: 6886092
    Abstract: A method and apparatus for processing data within a programmable gate array begins when a fixed logic processor that is embedded within the programmable gate array detects a custom operation code. The processing continues when the fixed logic processor provides an indication of the custom operational code to the programmable gate array. The processing continues by having at least a portion of the programmable gate array, which is configured as a dedicated processor, performing a fixed logic routine upon receiving the indication from the fixed logic processor.
    Type: Grant
    Filed: November 19, 2001
    Date of Patent: April 26, 2005
    Assignee: Xilinx, Inc.
    Inventors: Stephen M. Douglass, Ahmad R. Ansari
  • Patent number: 6798239
    Abstract: Interconnecting logic provides connectivity of an embedded fixed logic circuit, or circuits, with programmable logic fabric of a programmable gate array such that the fixed logic circuit functions as an extension of the programmable logic fabric. The interconnecting logic includes interconnecting tiles and may further include interfacing logic. The interconnecting tiles provide selective connectivity between inputs and/or outputs of the fixed logic circuit and the interconnects of the programmable logic fabric. The interfacing logic, when included, provides logic circuitry that conditions data transfers between the fixed logic circuit and the programmable logic fabric.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: September 28, 2004
    Assignee: Xilinx, Inc.
    Inventors: Stephen M. Douglass, Steven P. Young, Nigel G. Herron, Mehul R. Vashi, Jane W. Sowards
  • Patent number: 6693452
    Abstract: Interconnecting logic provides connectivity of an embedded fixed logic circuit, or circuits, with programmable logic fabric of a programmable gate array such that the fixed logic circuit functions as an extension of the programmable logic fabric. The interconnecting logic includes interconnecting tiles and may further include interconnecting logic. The interconnecting tiles provide selective connectivity between inputs and/or outputs of the fixed logic circuit and the interconnects of the programmable logic fabric. The interconnecting logic, when included, provides logic circuitry that conditions data transfers between the fixed logic circuit and the programmable logic fabric. The invention is directed towards the various needs and requirements of the layout and floor planning of a device having both fixed logic circuitry and programmable logic circuitry.
    Type: Grant
    Filed: February 25, 2002
    Date of Patent: February 17, 2004
    Assignee: Xilinx, Inc.
    Inventors: Ahmad R. Ansari, Stephen M. Douglass
  • Patent number: 6662285
    Abstract: A data processing system having a user configurable memory controller, one or more local block RAMs, one or more global block RAMs and a processor core can be configured in a single field programmable gate array (FPGA). The address depth of the global block RAMs and the number of wait states can be selected by a user, and they can be set either prior to configuration of the FPGA or programmed using instructions of the processor core. The number of wait states of the local block RAM is also user selectable. An algorithm that can optimize the address depth and the number of wait states to achieve a performance level is also disclosed. The present invention can be applied to designs having separate instruction and data sides.
    Type: Grant
    Filed: July 27, 2001
    Date of Patent: December 9, 2003
    Assignee: Xilinx, Inc.
    Inventors: Stephen M. Douglass, Prasad L. Sastry, Mehul R. Vashi, Robert Yin
  • Publication number: 20030062922
    Abstract: Interconnecting logic provides connectivity of an embedded fixed logic circuit, or circuits, with programmable logic fabric of a programmable gate array such that the fixed logic circuit functions as an extension of the programmable logic fabric. The interconnecting logic includes interconnecting tiles and may further include interfacing logic. The interconnecting tiles provide selective connectivity between inputs and/or outputs of the fixed logic circuit and the interconnects of the programmable logic fabric. The interfacing logic, when included, provides logic circuitry that conditions data transfers between the fixed logic circuit and the programmable logic fabric.
    Type: Application
    Filed: September 28, 2001
    Publication date: April 3, 2003
    Applicant: Xilinx, Inc.
    Inventors: Stephen M. Douglass, Steven P. Young
  • Patent number: 6522167
    Abstract: A data processing system having a user configurable memory controller, one or more block RAMS, and a processor core can be configured in a single field programmable gate array (FPGA). The address depth of the block RAMs and the number of wait states can be selected by a user, and they can be set either prior to configuration of the FPGA or programmed using instructions of the processor core. An algorithm that can optimize the address depth and the number of wait states to achieve a performance level is also disclosed. The present invention can be applied to designs having separate instruction and data sides.
    Type: Grant
    Filed: January 9, 2001
    Date of Patent: February 18, 2003
    Assignee: Xilinx, Inc.
    Inventors: Ahmad R. Ansari, Stephen M. Douglass, Mehul R. Vashi, Steven P. Young
  • Patent number: 6243664
    Abstract: Methods for designing a programmable interconnect matrix having reduced connectivity to achieve maximum routability for the reduced connectivity. An array of multiplexors, each having a multiplexor width wmux that is less than number of input conductors for the programmable matrix, are coupled to the input conductors of the programmable interconnect matrix such that the number of input signals shared between any two multiplexors is less than the multiplexor width wmux and such that each input signal has approximately the same number of chances to route. To better ensure the successful routing of input signals by a programmable interconnect matrix designed according to the present methods, improved routing methods are also described. According to a first embodiment, routing is accomplished by swapping successfully routed input signals with a blocked input signal and determining whether the input signal that has been swapped out may be routed through available multiplexors.
    Type: Grant
    Filed: October 27, 1998
    Date of Patent: June 5, 2001
    Assignee: Cypress Semiconductor Corporation
    Inventors: Hagop A. Nazarian, Stephen M. Douglass, W. Alfred Graf, S. Babar Raza, Sundar Rajan, Shiva Sorooshian Borzin, Darren Neuman
  • Patent number: 5923868
    Abstract: Methods for designing a programmable interconnect matrix having reduced connectivity to achieve maximum routability for the reduced connectivity. An array of multiplexors, each having a multiplexor width w.sub.mux that is less than number of input conductors for the programmable matrix, are coupled to the input conductors of the programmable interconnect matrix such that the number of input signals shared between any two multiplexors is less than the multiplexor width w.sub.mux and such that each input signal has approximately the same number of chances to route. To better ensure the successful routing of input signals by a programmable interconnect matrix designed according to the present methods, improved routing methods are also described. According to a first embodiment, routing is accomplished by swapping successfully routed input signals with a blocked input signal and determining whether the input signal that has been swapped out may be routed through available multiplexors.
    Type: Grant
    Filed: October 23, 1997
    Date of Patent: July 13, 1999
    Assignee: Cypress Semiconductor Corp.
    Inventors: Hagop A. Nazarian, Stephen M. Douglass, W. Alfred Graf, S. Babar Raza, Sundar Rajan, Shiva Sorooshian Borzin, Darren Newman
  • Patent number: 5848066
    Abstract: Methods for designing a programmable interconnect matrix having reduced connectivity to achieve maximum routability for the reduced connectivity. An array of multiplexors, each having a multiplexor width w.sub.mux that is less than number of input conductors for the programmable matrix, are coupled to the input conductors of the programmable interconnect matrix such that the number of input signals shared between any two multiplexors is less than the multiplexor width w.sub.mux and such that each input signal has approximately the same number of chances to route. To better ensure the successful routing of input signals by a programmable interconnect matrix designed according to the present methods, improved routing methods are also described. According to a first embodiment, routing is accomplished by swapping successfully routed input signals with a blocked input signal and determining whether the input signal that has been swapped out may be routed through available multiplexors.
    Type: Grant
    Filed: August 30, 1996
    Date of Patent: December 8, 1998
    Assignee: Cypress Semiconductor Corp.
    Inventors: Hagop A. Nazarian, Stephen M. Douglass, W. Alfred Graf, S. Babar Raza, Sundar Rajan, Shiva Sorooshian Borzin, Darren Neuman
  • Patent number: 5701092
    Abstract: An OR array including a first multiplicity of OR devices, to which a second multiplicity of product term signals are variably distributed. Some product term signals are distributed to four OR devices, other product term signals are distributed two or three OR devices, and still other product term signals are distributed to only one OR device.
    Type: Grant
    Filed: July 28, 1995
    Date of Patent: December 23, 1997
    Assignee: Cypress Semiconductor Corp.
    Inventors: Norman P. Taffe, Stephen M. Douglass, Hagop Nazarian
  • Patent number: 5689686
    Abstract: Methods for designing a programmable interconnect matrix having reduced connectivity to achieve maximum routability for the reduced connectivity. An array of multiplexors, each having a multiplexor width w.sub.mux that is less than number of input conductors for the programmable matrix, are coupled to the input conductors of the programmable interconnect matrix such that the number of input signals shared between any two multiplexors is less than the multiplexor width w.sub.mux and such that each input signal has approximately the same number of chances to route. To better ensure the successful routing of input signals by a programmable interconnect matrix designed according to the present methods, improved routing methods are also described. According to a first embodiment, routing is accomplished by swapping successfully routed input signals with a blocked input signal and determining whether the input signal that has been swapped out may be routed through available multiplexors.
    Type: Grant
    Filed: March 21, 1997
    Date of Patent: November 18, 1997
    Assignee: Cypress Semiconductor Corp.
    Inventors: Hagop A. Nazarian, Stephen M. Douglass, W. Alfred Graf, S. Babar Raza, Sundar Rajan, Shiva Sorooshian Borzin, Darren Neuman
  • Patent number: 5621338
    Abstract: A user configurable circuit contains clock logic, a switching element and a data path circuit. Input data is received in the switching element, and the switching element and the data path circuit constitute the entire data path for the circuit. A plurality of user configurable inputs are received to configure the circuit for a particular user application. The clock logic and the switching element implement a logic function that is configurable by the user configurable inputs. The logic function is pre-processed in the clock logic so that minimal delay occurs in the data path. In addition, the propagation delay through the switching element and the register is independent of the user configurable inputs. The user configurable circuit of the present invention has application for use as a macro cell for a programmable logic device permitting the user to configure the circuit as a D-type flip-flop, a T-type flip-flop. In addition, the user selects the polarity for the output circuit.
    Type: Grant
    Filed: January 11, 1996
    Date of Patent: April 15, 1997
    Assignee: Cypress Semiconductor Corp.
    Inventors: Lin-Shih Liu, Syed B. Raza, Hagop Nazarian, George M. Ansel, Stephen M. Douglass, Jeffery S. Hunt
  • Patent number: RE37577
    Abstract: A user configurable circuit contains clock logic, a switching element and a data path circuit. Input data is received in the switching element, and the switching element and the data path circuit constitute the entire data path for the circuit. A plurality of user configurable inputs are received to configure the circuit for a particular user application. The clock logic and the switching element implement a logic function that is configurable by the user configurable inputs. The logic function is pre-processed in the clock logic so that minimal delay occurs in the data path. In addition, the propagation delay through the switching element and the register is independent of the user configurable inputs. The user configurable circuit of the present invention has application for use as a macro cell for a programmable logic device permitting the user to configure the circuit as a D-type flip-flop, a T-type flip-flop. In addition, the user selects the polarity for the output circuit.
    Type: Grant
    Filed: March 24, 1998
    Date of Patent: March 12, 2002
    Assignee: Cypress Semiconductor Corporation
    Inventors: Lin-Shih Liu, Syed Babar Raza, Hagop Nazarian, George M. Ansel, Stephen M. Douglass, Jeffrey Scott Hunt