Abstract: Described are methods and circuits for identifying defective device layers and localizing defects. Production PLD tests extract statistically significant data relating failed interconnect resources to the associated conductive metal layer. Failure data thus collected is then analyzed periodically to identify layer-specific problems. Test circuits in accordance with some embodiments employ interconnect resources heavily weighted in favor of specific conductive layers to provide improved layer-specific failure data. Some such test circuits are designed to identify open defects, while others are designed to identify short defects.

Abstract: A floor planner tool for integrated circuit design which provides tools and displays for a designer to create a floor plan to define desired placement of circuits defined in a logical netlist by creating a physical hierarchy comprised of nested pblocks. Each pblock is a data structure which contains data which defines which circuits from the logical netlist are assigned to it. Each pblock stands alone and can be input to a place and route tool without the rest of the physical hierarchy. Each pblock data structure contains pointers to the circuits on the netlist assigned to that plbock, identifies other pblocks nested within it and contains at least a list of boundary pins for that pblock. Net data structures in the physical hierarchy define which nets are connected to which pins. PCellview data structures define the internal structure of each pblock.

Abstract: A configurable logic element (CLE) for a field programmable gate array (FPGA) includes “expanders”, i.e., connectors that allow fast signal communication between logic blocks. Expanders allow the configurable interconnection of a plurality of logic blocks, or portions thereof, to form a single logical entity that can implement large user circuits such as PALs, lookup tables, multiplexers, tristate buffers, and memories. One embodiment includes a configurable logic block. In a first mode, the logic block provides two N-input LUTs having N shared inputs and two separate outputs. The outputs are then combined using an expander to generate an (N+1)-input function. In a second mode, the logic block provides two N-input LUTs having M unshared inputs. An optional third mode provides a plurality of product term output signals based on the values of the N input signals.

Abstract: A method of implementing a user integrated circuit (IC) design in a tree representation includes the step of introducing the tree representation for the user IC design in a partitioned manner including at least one sub-design to form a design abstraction of the user design. At least one sub-design can include a sub-design providing for multiple levels of implementation hierarchy. The method can further include the step of traversing the design abstraction in a top-down fashion to provide functions selected among floor planning, port assignment, and timing budgeting for at least one sub-design, and the step of traversing the design abstraction in a bottom-up fashion to facilitate at least one among resolution of resource conflicts and parallel processing of multiple sub-designs. Traversing the design abstraction in the bottom-up fashion can facilitate a re-budgeting of timing for the integrated circuit design.

Abstract: Apparatus for signal distribution, and more particularly to a clock-distribution network in an integrated circuit, is described. A programmable logic device 300 includes an input buffer (814, 824) and an input signal distribution buffer (369) coupled to the input buffer (814, 824). The input signal distribution buffer (369) is configured to distribute a clock signal (902) within an input/output block clock region (304A, 304B). Signal lines (371UD) extend to at least one other input signal distribution buffer (369).

Abstract: A method of estimating congestion for a programmable logic device can include calculating a number of fan-in paths for each resource in the programmable logic device and calculating a number of fan-out paths for each resource in the programmable logic device. For each resource of the programmable logic device, a number of paths having different path characteristics can be determined and a probability can be assigned thereto. One or more measures of congestion can be computed according to the determining step.

Abstract: An integrated circuit (IC) includes multiple embedded test circuits that all include a ring oscillator coupled to a test load. The test load either is a direct short in the ring oscillator or else is a interconnect load that is representative of one of the interconnect layers in the IC. A model equation is defined for each embedded test circuit, with each model equation specifying the output delay of its associated embedded test circuit as a function of Front End OF the Line (FEOL) and Back End Of the Line (BEOL) parameters. The model equations are then solved for the various FEOL and BEOL parameters as functions of the test circuit output delays. Finally, measured output delay values are substituted in to these parameter equations to generate actual values for the various FEOL and BEOL parameters, thereby allowing any areas of concern to be quickly and accurately identified.

Abstract: Method and apparatus for forming timing parameters for a circuit design having a predefined routing topology within an integrated circuit is described. Sets of timing attributes are determined for the routing topology, each set of timing attributes being associated with one of a plurality of locations within the integrated circuit in which the circuit design may be placed. Timing parameters are formed in response to the sets of timing attributes. The timing parameters are then associated with the routing topology.

Abstract: A random access memory (RAM) in a programmable logic device (PLD) supports error correction as well as a configurable data width. The number of bits in a user data word varies by the selected configuration of the RAM, while the number of bits in the error correction code (ECC) is unvarying, and is based on the total width of the memory. In some embodiments, separate ports are provided for the user data and the ECC data. Thus, ECC data can be written to an ECC portion of the RAM array at a given RAM address, while at the same time user data is written to or read from a configurable user data portion of the RAM array at the same RAM address. In other embodiments, a single memory access port is used for both user data and ECC data.

Abstract: Method and apparatus for a wireless local area network programmable logic device is described. More particularly, a field programmable gate array (FPGA) is coupled to memory having programming instructions for configuring the FPGA with a medium access layer selected from more than one type of medium access layers. A physical layer is hardwired or embedded on the FPGA, or a separate integrated circuit for the physical layer is used. Additionally, the memory comprises programming instructions for a baseband controller, and may include programming instructions for a baseband processor, for configuring the FPGA in accordance therewith. In this manner, a single physical layer may be used with an FPGA to provide a multi-platform application specific standard product (ASSP). This is especially advantageous for providing multi-platform devices for use in countries or applications where one or more standards may be employed.

Abstract: Methods of routing a design in a programmable logic device (PLD) to increase the effectiveness of applying a multi-frame write (MFW) compression technique to the resulting configuration bitstream. The methods apply placement patterns and/or routing templates to encourage the inclusion of numbers of duplicated routing paths in the routed design. The duplicated routing paths result in duplicated configuration data. Thus, a configuration bitstream implementing the routed design in the PLD includes numbers of duplicated configuration data frames, and is well-suited to benefit from MFW compression techniques.

Abstract: According to one example embodiment, a complex, programmable logic device (CPLD-type) has logic blocks and Input/Output (I/O) pads interconnected via a programmable interconnect array. A dedicated logic block is directly coupled to I/O pads, which provides external access to the dedicated logic block without traversing the programmable interconnect array. The dedicated logic block may include a clock divider module for providing a divided clock to the CPLD.

Abstract: A system for distributing a small signal differential signal to a circuit element. The system includes: a first converter configured to convert a first small signal differential signal to a first two phase full CMOS differential signal for input into the differential multiplexer; and a programmable driver circuit configured to boost an output current of the programmable driver circuit at selected frequencies and to convert two phase full CMOS differential signal outputs of the differential multiplexer to a second small signal differential signal.

Abstract: Disclosed are methods and circuits that enable PLD vendors to dedicate PLDs for use with one or more specified designs. The PLD is programmed to store an indicator related to a specific design, for example, a hash function of the design, and to compare an indicator calculated within the PLD from an expression of the design (such as a bitstream) with the stored indicator. Only if the comparison matches is the PLD programmed to implement the design.

Abstract: Method and apparatus for simulating operations of a circuit design that includes high-level components and HDL components. Groups of HDL components are associated with different co-simulation engines. The high-level components of the design are simulated in a high-level modeling system (HLMS), and the HDL components in each group are simulated on the associated co-simulation engine.

Abstract: Method and apparatus for design verification with equivalency checking is described. More particularly, an integrated circuit design for a device having programmable logic is obtained, and a test case design having one or more test patterns is obtained to test the integrated circuit design. Memory states for the test patterns are obtained and applied to configure at least a programmable logic portion of the integrated circuit design with at least one test pattern to provide a configured design. Equivalency checking with the at least one test pattern and the configured design may be done to determine if the configured design is functionally equivalent to the at least one test pattern.

Abstract: A memory includes a plurality of row segments, with each row segment having a number of memory cells coupled to a corresponding dataline segment pair. Dataline driver circuits are provided between row segments to buffer signals on adjacent dataline segments. A control circuit is coupled to at least one row segment, and provides control signals to the at least one row segment and to the dataline driver circuits.

Abstract: According to one example embodiment, a buffer, e.g., in a clock/signal distribution apparatus is provided that substantially reduces jitter due to power supply noise. Decoupler and input stage isolates load from the top rail power supply (VDD). In a more particular embodiment, jitter contributions from the bottom rail power supply (VSS) can be minimized by cross-coupled load devices within load. Substantial independence from process and temperature is facilitated through the use of current bias, such as Proportional to Absolute Temperature (PTAT) current bias.

Abstract: A method of designing an integrated circuit using a general purpose programming language can include identifying a number of instances of each class allocated in a programmatic design implemented using the general purpose programming language and modeling the global memory of the programmatic design. A data flow between the modeled global memory and instructions of the programmatic design which access object fields can be determined and access to the modeled global memory can be scheduled. The programmatic design can be translated into a hardware description of the integrated circuit using the modeled global memory, the data flow, and the scheduled memory access.

Abstract: 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.