Patents Assigned to Xilinx, Inc.
  • Publication number: 20060006901
    Abstract: A Transmit line driver with selectable pre-emphasis and driver signal magnitudes comprises a primary current driver for setting a primary current level and a pre-emphasis current driver that provides an additional amount of current that is superimposed with or added to the primary current level produced by the primary current driver. The pre-emphasis current has either negative or positive magnitude based upon a pre-emphasis signal logic state. A first current selection module defines a reference signal that is used to select the primary current driver output signal magnitude in a first current mirror, while a second current selection module is used to define a second reference signal that selects a pre-emphasis current driver signal magnitude in a second current mirror. Logic generates a binary signal to both the first and second current selection modules to select the current levels as well as the pre-emphasis signal.
    Type: Application
    Filed: September 1, 2005
    Publication date: January 12, 2006
    Applicant: Xilinx, Inc.
    Inventors: Eric Groen, Charles Boecker, William Black
  • Patent number: 6984533
    Abstract: When integrated circuit dice are tested as part of a completely manufactured wafer, the individual die is tested both for proper function and for speed grade. A wafer map is formed in a computer to keep up with which dice on the wafer are good and to record the speed grade of each good die. This wafer map is then used during the step of dicing and packaging the wafer to fill existing orders by placing a die that meets a speed grade of an order into the package that has been ordered. More than one kind of order can be filled from dice in a single wafer. The method allows integrated circuit devices to be packaged to order and eliminates the need to keep an inventory of packaged dice.
    Type: Grant
    Filed: October 9, 2001
    Date of Patent: January 10, 2006
    Assignee: Xilinx, Inc.
    Inventors: Ramon R. Regos, Alelie T. Funcell
  • Patent number: 6985096
    Abstract: Method and apparatus for a bimodal serial to parallel converter is provided. A first stage of registers is clocked responsive to a clock signal, such as a forwarded clock signal of a synchronous interface. The first stage of registers is configurable in either a single serial shift chain or two serial shift chains. The former configuration is for Single Data Rate (“SDR”) data, and the latter configuration is for Double Data Rate (“DDR”) data. A bitslip controller is configured to provide a control select signal to selection circuitry. For DDR operation, the control signal is for selecting respective portions of outputs from the two serial shift chains for providing to a second stage of registers. For DDR operation, the second stage of registers is alternatively clocked responsive to a divided down version of the clock signal and another divided down version of the clock signal which is periodically stopped.
    Type: Grant
    Filed: August 17, 2004
    Date of Patent: January 10, 2006
    Assignee: Xilinx, Inc.
    Inventors: Paul T. Sasaki, Jason R. Bergendahl, Atul Ghia, Jian Tan
  • Patent number: 6985980
    Abstract: A scheme for freezing the clock of a CSOC to obtain a static view of the hardware for debugging purposes. A breakpoint unit is programmed to break on specific conditions or sequence of events. The breakpoint unit monitors the bus. Upon the occurrence of the programmed event the breakpoint unit generates a clock freeze signal. The clock freeze event signal is input to the bus arbiter which causes the bus arbiter to stop granting access to the bus to any bus master except the debug port. The bus arbiter checks for pending transactions on the bus and monitors the completion of any pending transactions. This ensures that the system will not be frozen while in a wait state which would render the bus inoperable. Once all pending transactions are complete, the bus arbiter generates a qualified clock freeze signal to the CSL clock thereby freezing the system for debugging.
    Type: Grant
    Filed: November 3, 2000
    Date of Patent: January 10, 2006
    Assignee: Xilinx, Inc.
    Inventor: Jean-Didier Allegrucci
  • Patent number: 6985019
    Abstract: A selectively enabled clamp circuit for limiting voltage overshoot on an input/output (I/O) pin of an associated integrated circuit (IC) device includes a single discharge transistor and a select circuit. The single discharge transistor is connected between the I/O pin and ground potential, and the select circuit is coupled to the I/O pin and includes an input to receive an enable signal and an output coupled to a gate of the signal discharge transistor. For some embodiments, the select circuit includes a level shifter circuit and a voltage detection circuit.
    Type: Grant
    Filed: April 13, 2004
    Date of Patent: January 10, 2006
    Assignee: Xilinx, Inc.
    Inventors: Shi-dong Zhou, Ping Zhang, Ronald L. Cline
  • Patent number: 6983394
    Abstract: Method and apparatus for providing a measure of jitter and skew of a clock signal is described. The clock signal may be used as an input to a digital circuit. In one embodiment, a digital delay circuit is used in conjunction with a processing circuit to continuously measure the jitter of an input clock signal, thus providing clock signal performance measurement over time. In another embodiment, a pair of digital delay circuits are used to continuously measure the skew or delay between a reference clock signal and a input clock signal, thus providing a measurement of the skew of the input clock signal over time. The digital delay circuit(s) are formed on-chip, and thus an on-chip determination of jitter or skew may be provided.
    Type: Grant
    Filed: January 24, 2003
    Date of Patent: January 3, 2006
    Assignee: Xilinx, Inc.
    Inventors: Shawn K. Morrison, Andrew K. Percey, John D. Logue, James M. Simkins, Nicholas J. Sawyer
  • Patent number: 6983439
    Abstract: Method and apparatus are described for a placer system for placing design objects onto an arrayed architecture, such as a programmable logic device including an FPGA. More particularly, a placer interface is described for communicating with a placer core. The placer interface receives information from external entities, and unifies and generalizes this information for the placer core. The external entities comprise different representations of architecture, design, device, constraints and algorithm-dictated placer-movable objects.
    Type: Grant
    Filed: October 29, 2002
    Date of Patent: January 3, 2006
    Assignee: Xilinx, Inc.
    Inventors: James L. Saunders, Krishnan Anandh, Guenter Stenz, Sudip K. Nag, Jason H. Anderson
  • Patent number: 6983405
    Abstract: A circuit that includes a core device that is embedded within fixed interfacing logic circuitry that, in turn, is embedded in an FPGA fabric. The FPGA fabric may be configured into a test mode of operation to test either the embedded device or fixed logic devices formed within the fixed interfacing logic. While the FPGA is configured in a test mode, test circuitry and communication paths are made present within the fixed interfacing logic circuitry to facilitate the testing. Additionally, the test circuitry comprises isolation circuitry that is formed between various modules and circuits that are to be tested to isolate the device under test and to produce test signals thereto and therefrom during testing operations.
    Type: Grant
    Filed: November 16, 2001
    Date of Patent: January 3, 2006
    Assignee: Xilinx, Inc.,
    Inventors: Nigel G. Herron, Eric J. Thorne, Qingqi Wang
  • Patent number: 6982451
    Abstract: SEU-hardening series resistances loads are formed within the gate structures of cross-coupled inverters of a latch. For some embodiments, the gate contact for the input of each cross-coupled inverter has a sufficiently high resistance to provide the SEU-hardening series resistance. For other embodiments, a conductive trace layer coupled to the input of each cross-coupled inverter includes a high-resistivity portion that provides the SEU-hardening series resistance.
    Type: Grant
    Filed: March 27, 2003
    Date of Patent: January 3, 2006
    Assignee: Xilinx, Inc.
    Inventors: Martin L. Voogel, Austin H. Lesea, Joseph J. Fabula, Carl H. Carmichael, Shahin Toutounchi, Michael J. Hart, Steven P. Young, Kevin T. Look, Jan L. de Jong
  • Patent number: 6980035
    Abstract: A technique and circuit implementation are described for automatically detecting a change in a power supply voltage and selectively reconfiguring a circuit for optimized performance at the changed voltage. One application of particular interest is an auto-detect level shifter. The auto-detect level shifter can be used in an output driver and can be automatically enabled if it is needed to optimize performance for various I/O standards, including those that operate at different voltages.
    Type: Grant
    Filed: March 18, 2003
    Date of Patent: December 27, 2005
    Assignee: Xilinx, Inc.
    Inventors: Shi-dong Zhou, Gubo Huang, Shankar Lakkapragada, Andy T. Nguyen, Fariba Farahanchi
  • Patent number: 6981091
    Abstract: Structures and methods for transferring data from non-volatile to volatile memories. An extra bit, called a “transfer bit”, is included in each data word. The transfer bit is set to the programmed value, and is monitored by a control circuit during the memory transfer. If the supply voltage is sufficient for correct programming, the transfer bit is read as “programmed”, and the data transfer continues. If the supply voltage is below the minimum supply voltage for proper programming, the transfer bit is read as “erased”, and the data transfer is reinitiated. In one embodiment, a second transfer bit set to the “erased” value is included in each word.
    Type: Grant
    Filed: October 25, 2001
    Date of Patent: December 27, 2005
    Assignee: Xilinx,Inc.
    Inventors: Schuyler E. Shimanek, Roy D. Darling
  • Patent number: 6980026
    Abstract: Structures and methods that can be used to reduce power consumption in programmable logic devices (PLDs). Varying delays on the input paths of a PLD lookup table (LUT) can cause the nodes within the LUT (including the LUT output signal) to change state several times each time the input signals change state. Therefore, a programmable logic block for a PLD is provided that registers the LUT input signals instead of, or in addition to, the LUT output signal. The delays on the input paths are equalized and “glitching” on the LUT nodes is greatly reduced or eliminated. Thus, power consumption is reduced. Methods are also provided of reducing power consumption in PLDs by replacing single-bit registers on LUT output signals with multi-bit registers on LUT input signals, or by including multi-bit input registers in addition to the single-bit output registers.
    Type: Grant
    Filed: December 16, 2003
    Date of Patent: December 27, 2005
    Assignee: Xilinx, Inc.
    Inventor: Stephen M. Trimberger
  • Patent number: 6980045
    Abstract: A charge pump circuit for generating various pumped voltages includes a first charge pump including a plurality of first charge pump stages responsive to a first set of clock signals and having threshold voltage cancellation circuitry, a second charge pump including a plurality of second charge pump stages responsive to a second set of clock signals different from the first clock signals, and a switching circuit configured to selectively connect the second charge pump in series between the first charge pump and a voltage rail in response to a mode signal (MODE). For some embodiments, a plurality of the charge pump circuits can be selectively connected in parallel in response to corresponding select signals to generate various drive currents.
    Type: Grant
    Filed: December 5, 2003
    Date of Patent: December 27, 2005
    Assignee: Xilinx, Inc.
    Inventor: Ping-Chen Liu
  • Patent number: 6980030
    Abstract: Integrated circuits are disclosed that have interconnected programmable logic, and configuration memory. The interconnected programmable logic is connected by a logical interconnection network. The integrated circuits have a configurable function unit including a function unit component, such as a counter or shift register. The integrated circuits further include a configurable decoder, which decodes a value presented by the function unit component based on decoder configuration data. The integrated circuits also have at least one decoder output, which provides information about a comparison of the decoder configuration data with the value presented by the function unit component.
    Type: Grant
    Filed: June 26, 2003
    Date of Patent: December 27, 2005
    Assignee: Xilinx, Inc.
    Inventors: Frank C. Wirtz, II, John R. Hubbard, Jeffrey H. Seltzer, Schuyler E. Shimanek
  • Patent number: 6978541
    Abstract: Disclosed is apparatus to enhance thermal energy transfer from a heater to a DUT in IC handler systems. The pick-up head of an IC handler system is made of metal blocks in maximal thermal contact, and further includes an electrically resistive and thermally conductive layer. The electrically resistive layer provides ESD protection to the DUT. The preferred apparatus uses a collapsible billows suction cup to secure, pick-up, and align DUTs.
    Type: Grant
    Filed: October 1, 2002
    Date of Patent: December 27, 2005
    Assignee: Xilinx, Inc.
    Inventors: Thomas A. Feltner, John C. Marley
  • Patent number: 6981232
    Abstract: An application specific processor for an application program is provided. First a software description, for example, a HDL description, of a processor is created. A user program is written using the processor's instruction set and compiled and/or assembled into object code. The software description of the processor and the object code are combined and synthesized into a logic gate circuit description, which may be implemented in a Field Programmable Gate Array (FPGA), a Complex Programmable Logic Device (CPLD) or any other Integrated Circuit (IC) having programmable logic modules. Typically, the logic gate circuit description is optimized, hence reducing the number of logic gates and the resources needed.
    Type: Grant
    Filed: May 23, 2003
    Date of Patent: December 27, 2005
    Assignee: Xilinx, Inc.
    Inventors: Scott Te-Sheng Lien, John R. Hubbard
  • Patent number: 6981153
    Abstract: It is sometimes desirable to protect a design used in a PLD from being copied. If the design is stored in a different device from the PLD and read into the PLD through a bitstream, the design may be encrypted as it is read into the PLD and decrypted within the PLD before being loaded into configuration memory cells for configuring the PLD. According to the invention, in such a device, a method is provided to prevent the design from being read back from the PLD in its decrypted state if it had been encrypted when loaded into the PLD.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: December 27, 2005
    Assignee: Xilinx, Inc.
    Inventors: Raymond C. Pang, Walter N. Sze, John M. Thendean, Stephen M. Trimberger, Jennifer Wong
  • Patent number: 6978433
    Abstract: Method and apparatus for placement of vias is described. More particularly, source power and ground vias are placed in partial response to locations where conductive lines cross over a reserved region. The reserved region is reserved for an embedded device, and is reserved in a layout database of a host device.
    Type: Grant
    Filed: September 16, 2002
    Date of Patent: December 20, 2005
    Assignee: Xilinx, Inc.
    Inventors: Andy H. Gan, Nigel G. Herron
  • Patent number: 6977959
    Abstract: A clock recovery circuit that operates at a clock speed equal to one-half the input data rate is presented. The clock recovery circuit uses dual input latches to sample the incoming serial data on both the rising edge and falling edge of a half-rate clock signal to provide equivalent full data rate clock recovery. The clock recovery circuit functions to maintain the half-rate clock transitions in the center of the incoming serial data bits. The clock recovery circuit includes a phase detector, charge pump, controlled oscillation module and a feedback module. The phase detector produces information on the phase and data transitions in the incoming data signal to the charge pump. Generally, the circuit is delay insensitive and receives phase and transition information staggered relative to each other.
    Type: Grant
    Filed: January 17, 2003
    Date of Patent: December 20, 2005
    Assignee: Xilinx, Inc.
    Inventors: Brian T. Brunn, Ahmed Younis, Shahriar Rokhsaz
  • Patent number: 6978427
    Abstract: A method and apparatus for implementing fast sum-of-products logic in a field programmable gate array (FPGA) is disclosed. The method includes literal-sharing decomposition of the sum-of-products logic to reduce the number of configurable logic block (CLB) slices required to implement wide fan-in logic functions on an FPGA. The decomposition is performed by combining product terms having similar literal patterns. The apparatus includes a CLB including a plurality of slices and a second-level logic (separate from the slices) circuit to combine the outputs of the slices. Typically, the second-level logic is an OR gate or its equivalent that implements the sum portion of the sum-of-products expression. Alternatively, a combining gate may be included within the slice to combine the output of the slice with the output of another slice preceding the first slice.
    Type: Grant
    Filed: May 18, 2004
    Date of Patent: December 20, 2005
    Assignee: Xilinx, Inc.
    Inventor: Alireza S. Kaviani