Abstract: A lookup table (LUT) circuit comprises a multiplexer circuit having two modes. In a first mode, the multiplexer circuit functions as a standard multiplexer. In a second mode, the multiplexer circuit selects two or more stored values, where the two or more stored values have the same logical value. Thus, in the second mode the delay through the multiplexer circuit is reduced. In a PLD embodiment, two select terminals of the multiplexer are coupled to two different signal lines. When both signal lines are used, the multiplexer circuit is placed into the first mode. When only one of the signal lines is used, the multiplexer circuit is placed into the second mode, a value on the unused signal line is ignored, and two stored values are provided to the output terminal. Thus, the multiplexer circuit has a reduced path delay when one of the two signal lines is unused.

Abstract: An test block includes a box-like body and four rails extending from side edges of the body. During thermal testing, the test block is mounted between a test head and a test socket such that the rails provide a thermal path between the test block body and contact pads formed on the test socket. In this manner the rails emulate the thermal path formed by the metal leads extending from a conventional Quad Flat Pack Integrated Circuit (QFP IC), thereby reliably duplicating the actual thermal path of the QFP IC. The test block is mounted on the test system and its temperature is measured before and after testing QFP IC devices. Confirming that the test block is within test temperature specifications before and after the QFP-IC test procedure provides a highly reliable verification that the QFP-IC's actual test temperature is within the test temperature specifications.

Abstract: A method of inlining a function call of a first high level design language (HDL) into a second HDL is disclosed comprising the steps of: (a) translating the function call of the first HDL into a function body file of the second HDL; (b) translating a signature of the function call of the first HDL into a data file including predetermined data of the function signature; and (c) translating the function call of the first HDL into a sequence of macro definitions based on the corresponding data file followed by a compiler directive to include the corresponding function body file of the second HDL. In one embodiment, the first HDL is a VHDL and the second HDL is a Verilog HDL.

Abstract: The present invention is a programmable integrated circuit that can be used to handle different communication specifications. In one embodiment, the integrated circuit contains at least two physical layer modules, a media independent interface and a media access control module. The physical layer modules are preferably fixed logic components embedded in programmable logic fabric. In another embodiment, the integrated circuit contains a physical layer module and at least two media access control modules. The physical layer module is preferably a fixed logic component embedded in programmable logic fabric.

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, an unencrypted bitstream could be observed and copied as it is being loaded. According to the invention, a bitstream for configuring a PLD with an encrypted design includes unencrypted words for controlling loading of the configuration bitstream and encrypted words that actually specify the design.

Abstract: A buffer memory status detection circuit has a binary logic gate (e.g. an OR gate) coupled to a comparator output signal that is asserted when a sum of a first address pointer of a FIFO memory array plus a first offset equals a second address pointer, and to a reset signal. Binary logic provides a binary output (i.e. “0” or “1”) in a first clock domain to two synchronization registers in series that convert the output to a second clock domain. An optional pipeline register improves timing of the output in the second clock domain, and is particularly desirable for use with high-speed clocks.

Abstract: A method of processing a general-purpose, high level language program to determine a hardware representation of the program can include compiling the general-purpose, high level language program to generate a language independent model (105, 110, and 115). The language independent model can be scheduled such that each component is activated when both control and valid data arrive at the component (120). An interface structure specifying a hardware interface through which devices external to the language independent model interact with a physical implementation of the language independent model can be defined and included in the language independent model (200, 300, 400).

Abstract: A method and apparatus for selecting programmable interconnects to reduce clock skew is described. A routing tree for clock signals is created having routes and clock pin nodes. Delays of the clock signals to the clock pin nodes are determined. The routing tree is balanced to a target clock skew, such as zero clock skew, for the clock signals provided to the clock pin nodes. Programmable interconnect circuits are selectively added to reduce clock skews of the clock signals, where the clock skews being reduced at the clock pin nodes are for at least a portion of the clock pin nodes. Additionally described are determining clock propagation delays to clock pins and balancing a clock tree using computer aided design.

Abstract: Prior art storage techniques have certain limitations, including requiring additional external resources to implement and not making use of all of the available storage space. A method and apparatus using a header table and, in some cases, an alternative access interface are described which allow for more efficient use of available memory space, permit an arbitrary number of data streams to be stored and accessed with a minimal interface, and provide for a simple serial connection to chain multiple memory devices together.

Abstract: A multiplexer that can be used, for example, in a programmable logic device (PLD). The multiplexer includes a plurality of pass transistors passing a selected one of several input values to an internal node, which drives a buffer that provides the multiplexer output signal. The pass transistors can be controlled, for example, by values stored in memory cells of a PLD. The pass transistors have a first oxide thickness and are controlled by a value having a first operating voltage. The buffer includes transistors having a second and thinner oxide thickness, and is operated at a second and lower operating voltage. Where memory cells are used to control the pass transistors, the memory cells include transistors having the first oxide thickness and operate at the first operating voltage. Some embodiments also include transistors of varying gate length for each of the pass transistors, buffer transistors, and memory cell transistors.

Abstract: Method and apparatus are disclosed for analyzing defect data produced in testing a semiconductor chip from a logic design. In various embodiments, input for processing is a first inspection data set that identifies a first set of physical locations that are associated with defects detected during fabrication of the chip. Also input is a second test data set that includes one or more identifiers associated with failing circuitry in the chip. A second set of physical locations is determined from the one or more identifiers of failing circuitry, hierarchical relationships between blocks of the design, and placement information associated with the blocks. Each of the one or more identifiers is associated with at least one of the blocks. Correspondences are identified between physical locations in the first inspection data set and the second set of physical locations.

Abstract: Method and apparatus for placing and routing an electronic circuit design. Various embodiments are disclosed for analyzing placed and/or routed designs for power consumption characteristics and timing characteristics. New designs are iteratively generated in order to reduce power consumption and satisfy timing requirements of the design.

Abstract: An FPGA is readily connectable to a high-speed fiber optic link by snap fitting an external fiber optic cable into an accommodating duplex fiber optic connector of a low-profile packaged FPGA integrated circuit. The low-profile packaged FPGA integrated circuit includes a die-bonded assembly disposed within a co-fired multilayer ceramic integrated circuit package. The die-bonded assembly includes the optoelectronic die, the bottom surface of which is die-bonded and electrically interconnected by micropads to the upper surface of the core of an FPGA integrated circuit die. A first optical fiber communicates light from the connector, through the package, and to a photodetector on the optoelectronic die. A second optical fiber communicates light from a laser diode on the optoelectronic die, through the package, and to the connector. In some embodiments, a micromirror device is disposed within the package to redirect light between the optoelectronic die and the optical fibers.

Abstract: Method and apparatus for configuring a programmable logic device using configuration data stored in an external memory is described. In an example, a boundary scan port includes a data input terminal and a data output terminal. An instruction-set processor includes a first interface coupled to the boundary scan port and a second interface coupled to a configuration memory within the programmable logic device. The data output terminal of the boundary scan port is coupled to provide instruction data to the external memory and the data input terminal is coupled to receive configuration data from the external memory in response to the instruction data. The instruction-set processor is configured to provide configuration data to the configuration memory.

Abstract: A circuit for calibrating a resistance between a first circuit node and a second circuit node is disclosed. The circuit comprises a reference resistor connected between first and second reference nodes; a first transistor having a first current-handling terminal connected to the first reference node, a second current-handling terminal, and a first control terminal; and a second transistor having a third current-handling terminal connected to the first circuit node, a fourth current-handling terminal connected to the second circuit node, and a second control terminal connected to the first control terminal.

Abstract: Structures and methods of including processor capabilities in an existing PLD architecture with minimal disruption to the existing general interconnect structure. In a PLD including a column of block RAM (BRAM) blocks, the BRAM blocks are modified to create specialized logic blocks including a RAM, a processor, and a dedicated interface coupled between the RAM, the processor, and the general interconnect structure of the PLD. The additional area is obtained by increasing the width of the column of BRAM blocks. Because the interconnect structure remains virtually unchanged, the interconnections between the specialized logic blocks and the adjacent tiles are already in place, and the modifications do not affect the PLD routing software. In some embodiments, the processor can be optionally disabled, becoming transparent to the user. Other embodiments provide methods of modifying a PLD to include the structures and provide the capabilities described above.

Abstract: Output switch noise resulting from simultaneous switching is reduced by time multiplexing the output switching operation. A plurality of phase-shifted clock signals are generated such that each of the phase-shifted clock signals exhibits an active (e.g., rising) edge during a single period of the reference clock signal. Different groups of input/output blocks are switched in response to the various phase-shifted clock signals, such that output switching occurs at various times during the period of the reference clock signal. The phase-shifted clock signals can be generated with predetermined phase differences or with dynamically determined phase differences.

Abstract: Structures and methods for testing a re-programmable logic block embedded in a one-time programmable fabric in a PLD. The re-programmable logic block is tested without using the one-time programmable resources needed for implementing user circuits, by including a multiple input signature register (MISR) circuit coupled to receive output data from the re-programmable logic portion of the PLD. In some embodiments, a tester operating at a first and lower clock frequency can be used to test a re-programmable logic block operating at a second and higher clock frequency. In some of these embodiments, the one-time programmable fabric is tested at the first clock frequency.

Abstract: A oscillator controller (1300, 1500) is described. Differential logic receives a clock signal and an inverted version thereof (210, 210B) and an oscillator signal and an inverted version thereof (208, 208B), where the clock signal (210) and the oscillator signal (208) having different frequencies. The differential logic provides a differential output (1611, 1612) at least partially responsive to at least one of the clock signal and the oscillator signal. The differential logic is a combinational circuit in an oscillator alignment state and a sequential circuit in a hard-phase alignment state. Control signals (1317, 1318) are used in part to selectively alternate between putting the differential logic in the oscillator alignment state and in the hard-phase alignment state.

Abstract: A test cell and method of operation are disclosed. The test cell may be cascaded with other test cells to form a test structure that spans across any number of slices and/or tiles in a programmable logic device. The test structure behaves like a register, and may be used to test direct interconnects and any number their fan-out lines simultaneously.