Patents Represented by Attorney H. C. Chan
-
Patent number: 6871336Abstract: An incremental placement method uses a set of connections to optimize and a set of movable design objects. The movable design objects are unplaced. A plurality of anchoring connections is associated with the movable design objects. A set of weights is associated with the set of connections to optimize and the plurality of anchoring connections. An objective function is constructed using the set of connections to optimize, the plurality of anchoring connections, and the set of weights. The objective function is minimized to obtain a placement of the movable design objects.Type: GrantFiled: October 17, 2002Date of Patent: March 22, 2005Assignee: Xilinx, Inc.Inventor: Jason H. Anderson
-
Patent number: 6857115Abstract: Application of network flow techniques to constrained optimization problems is disclosed. The present of constrains may lead to infeasible solutions. The infeasible solutions can be removed by an iterative process of changing the structure of the network and/or the associated parameters. Specific applications of the invention to the placement of tristate buffers and clocks in integrated circuits are disclosed.Type: GrantFiled: August 8, 2002Date of Patent: February 15, 2005Assignee: Xilinx, Inc.Inventors: Srinivasan Dasasathyan, Guenter Stenz, Sudip K. Nag, Jason H. Anderson
-
Patent number: 6851101Abstract: A systematic method for calculating future cost is disclosed. Pre-routing is performed from a source node to other nodes through a series of neighboring nodes. At each node in the pre-routing, the cumulative routing cost and Manhattan distance are calculated. This cumulative routing cost is used as a new future cost for a specific distance if it is lower than or there is no existing future cost for that distance. A table can be used to store the future cost data. During routing, the recorded future cost is added to the cumulative cost of a node to help guide the routing, improving router run-time.Type: GrantFiled: June 19, 2003Date of Patent: February 1, 2005Assignee: Xilinx, Inc.Inventors: Raymond Kong, Jason H. Anderson
-
Patent number: 6839874Abstract: Method and apparatus for testing a device embedded in a programmable logic device is described. Because an embedded device, such as a microprocessor core, comprises more input and output pins than a programmable logic device, such as a field programmable gate array, in which it is located, providing a test vector wider than the number of external input and output pins of the programmable logic device is problematic. To solve this problem, at least a portion of the programmable logic device is programmed to function as a vector controller, where a test vector may be provided to the vector controller in sections, reassembled by the vector controller and provided to the embedded device after reassembly. Moreover, a test vector result in response to the test vector input is obtained by the vector controller and sectioned for outputting.Type: GrantFiled: February 28, 2002Date of Patent: January 4, 2005Assignee: Xilinx, Inc.Inventor: Ying Fang
-
Patent number: 6810508Abstract: A computer implemented apparatus and method that automates the entry, modification, analysis, and generation of test benches from electrical circuits, both of which are specified as hardware description language (HDL) files. The computer implemented-method and apparatus also provides a unique mechanism that blends entry and display of timing requirements that must be met by the electric circuit.Type: GrantFiled: October 7, 2002Date of Patent: October 26, 2004Assignee: Xilinx, Inc.Inventors: Andrew M. Bloom, Rodrigo J. Escoto
-
Patent number: 6798239Abstract: 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: GrantFiled: September 28, 2001Date of Patent: September 28, 2004Assignee: Xilinx, Inc.Inventors: Stephen M. Douglass, Steven P. Young, Nigel G. Herron, Mehul R. Vashi, Jane W. Sowards
-
Patent number: 6795960Abstract: The present invention provides a new method to handle a signal that crosses one or more areas in modular design of programmable logic devices. Even when the signal have an attribute disallowing the use of programmable interconnect points on an associated wire, the programmable interconnect points may still be used if the wire has no input programmable interconnect points outside of the attribute's associated area. This approach makes use of the programmable interconnect point directionalities and allows for more programmable interconnect points to be used while guaranteeing that the detailed routing solution is conflict free and absent of signal shorts.Type: GrantFiled: October 17, 2002Date of Patent: September 21, 2004Assignee: Xilinx, Inc.Inventor: Raymond Kong
-
Patent number: 6789244Abstract: Application of network flow techniques to constrained optimization problems is disclosed. The present of constrains may lead to infeasible solutions. The infeasible solutions can be removed by an iterative process of changing the structure of the network and/or the associated parameters. Specific applications of the invention to the placement of tristate buffers and clocks in integrated circuits are disclosed.Type: GrantFiled: August 8, 2002Date of Patent: September 7, 2004Assignee: Xilinx, Inc.Inventors: Srinivasan Dasasathyan, Guenter Stenz, Sudip K. Nag
-
Patent number: 6784685Abstract: A test arrangement is designed to test whether one in a chain of vias or contacts has abnormally high resistance. The arrangement contains a plurality of via or contact chains and a plurality of decoders. The chains are switchably connected to a resistance measurement device. Each decoder has a unique address such that it will generate a control signal when a predetermined address is address thereon. The control signal is used to close a switch, which connect one of the chains to the resistance measurement device. By sequentially applying different addresses to the decoders, the resistance of the chains can be individually measured.Type: GrantFiled: October 3, 2002Date of Patent: August 31, 2004Assignee: Xilinx, Inc.Inventors: Tai-An Chao, Zicheng Gary Ling, Shihcheng Hsueh
-
Patent number: 6781407Abstract: 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: GrantFiled: January 9, 2002Date of Patent: August 24, 2004Assignee: Xilinx, Inc.Inventor: David P. Schultz
-
Patent number: 6772406Abstract: Optimal routing line segments and associated buffers are pre-engineered for each family of ASIC chips by simulating wires segments of various lengths using distributed resistance and capacitance wire models, and by estimating crosstalk from neighboring line segments. During ASIC design, space is reserved on the ASIC substrate for fabricating the buffers, which are selectively connected by local metal and diffusion structures to form long distance interconnections. Signals are passed from an ASIC circuit structure to a selected long distance interconnection by connecting an output terminal of the ASIC structure either to the input terminal of a buffer located at one end of the interconnection, or by connecting the output terminal directed to a line segment of the interconnection.Type: GrantFiled: June 17, 2003Date of Patent: August 3, 2004Assignee: Xilinx, Inc.Inventor: Stephen M. Trimberger
-
Patent number: 6757879Abstract: The present invention provides a new method to handle power and ground signals in modular design of programmable logic devices. During module implementation, the power and ground signals of each module are associated with area constraint properties. When performing routing in the module implementation phase, the power and ground signals together with regular local signals of the module are routed in accordance with their respective area constraint properties. However, the area constraint properties of the power and ground signals are removed during assembly phase while the area constraint properties of the local signals are retained.Type: GrantFiled: October 9, 2002Date of Patent: June 29, 2004Assignee: Xilinx, Inc.Inventors: Raymond Kong, Sandor S. Kalman
-
Patent number: 6754882Abstract: A method for customization of the software of an FPGA-based SoC includes the steps of selecting (380) a system component used for customizing the FPGA-based SoC, configuring (382) the selected system component with parameters for use with the FPGA-based SoC and propagating (384) the parameters used to configure the selected system component to peer system components. The method further includes the step of configuring (388) the peer system components using the propagated parameters during customization of the FPGA-based SoC and creating (401) a software interface to the selected system components and to the peer system components.Type: GrantFiled: February 22, 2002Date of Patent: June 22, 2004Assignee: Xilinx, Inc.Inventors: Reno L. Sanchez, John H. Linn
-
Patent number: 6732348Abstract: The location of short and open faults in a programmable logic device can be precisely located. The programmable logic device contains a plurality of nets, and each net contains a plurality of PIPs and connected line segments. A faulty net is first identified using conventional methods. A new design is constructed from a faulty net by replacing one of the plurality of line segments or PIPs with an alternative line segment/PIP. The mew design is tested to determine if the fault has been removed as a result of the replacement. If the fault is not removed, another line segment/PIP is replaced. This process is repeated until a design without fault is found. The location of the faulty line segment/PIP can be easily deduced.Type: GrantFiled: September 7, 2001Date of Patent: May 4, 2004Assignee: Xilinx, Inc.Inventors: Mehdi Baradaran Tahoori, Shahin Toutounchi
-
Patent number: 6732309Abstract: A new method to test short faults in a programmable logic device is described. The line segments under test are connected together to form a conducting chain. All the line segments neighboring to the conducting chain are tied to a known state. A test vector is applied to the programmable logic device. The state of the line under test is measured. If it is the same as the known state, the programmable logic device is likely to have faults.Type: GrantFiled: August 2, 2001Date of Patent: May 4, 2004Assignee: Xilinx, Inc.Inventors: Shahin Toutounchi, Andrew W. Lai
-
Patent number: 6732349Abstract: Routing algorithms can be modified to increase the number of programmable interconnect points (PIPs) used in a routing pattern. A file is set up to store information on whether a PIP has been covered. The cost of a node can be decreased by a predetermined value if two nodes are connected by an uncovered PIP. In another embodiment, a file is set up to store a count for each PIP. The count is increased each time the PIP is used in a routing. The cost of a node can be increased by multiplying a predetermined value and the count of a PIP associated with the node.Type: GrantFiled: August 29, 2002Date of Patent: May 4, 2004Assignee: Xilinx, Inc.Inventors: Richard Yachyang Sun, Sandor S. Kalman, Sudip K. Nag
-
Patent number: 6725364Abstract: A programmable integrated circuit can be designed to emulate, on demand, one of several commonly used microprocessors. It contains a configurable instruction processing unit and a superset datapath unit. The instruction processing unit further contains a configurable microcode unit and a non-configurable sequencing unit. The programmable integrated circuit can be programmed so that a microcode compatible with a target microprocessor is installed in the configurable microcode unit. The superset datapath unit is a superset of the datapath elements of all the target microprocessors.Type: GrantFiled: March 8, 2001Date of Patent: April 20, 2004Assignee: Xilinx, Inc.Inventor: Eric J. Crabill
-
Patent number: 6714041Abstract: A method for reconfiguring a complex programmable logic device (CPLD) that includes an EEPROM array and a shadow SRAM array comprises reprogramming the EEPROM array with new configuration data while the CPLD is operating in a first configuration. This relatively time-consuming operation has no effect on CPLD operation since only the SRAM array controls the configuration of the CPLD. At a desired point in time, the new configuration data from the EEPROM array can be loaded into the SRAM array to reconfigure the CPLD. Because this loading of configuration data into the SRAM array takes only microseconds to perform, normal system operation effectively proceeds without interruption. A CPLD can include multiple EEPROM arrays, each storing a different set of configuration data, thereby allowing the CPLD to rapidly switch between various configurations by loading the configuration data from different EEPROM arrays into the SRAM array.Type: GrantFiled: August 30, 2002Date of Patent: March 30, 2004Assignee: Xilinx, Inc.Inventors: Roy D. Darling, Schuyler E. Shimanek, Thomas J. Davies, Jr.
-
Patent number: 6700510Abstract: A scalable physical coding sublayer (PCS) can be adjusted to provide different combinations of communication channels and data widths. The PCS can use 8B/10B encoders having a disparity input connection and at least one disparity output connection. In one embodiment, the encoder has both a synchronous and an asynchronous disparity output connection. The encoder can be coupled with additional encoders to provide an expanded width channel of 16B/20B encoding. Additional configurations are possible. In expanded operation, only one of the encoders needs to output special codes. The encoders, therefore, include a slave input connection to place the encoder in a slave mode so that a special code is replaced with an inert special code. All but one encoder in an expanded system are slave encoders. An idle input connection is also provided in the encoders to place the encoder in an idle mode where pre-defined data is output from the encoder.Type: GrantFiled: November 13, 2002Date of Patent: March 2, 2004Assignee: Xilinx, Inc.Inventors: Joseph Neil Kryzak, Thomas E. Rock
-
Patent number: 6693452Abstract: 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: GrantFiled: February 25, 2002Date of Patent: February 17, 2004Assignee: Xilinx, Inc.Inventors: Ahmad R. Ansari, Stephen M. Douglass