Abstract: In accordance with an embodiment of the present invention, a programmable logic device includes configuration memory to store configuration data to configure the programmable logic device, and a non-volatile memory to store configuration data for transfer to the configuration memory to configure the programmable logic device. The non-volatile memory also stores a first code value based on the configuration data stored in the non-volatile memory. A code block calculates a second code value based on the configuration data transferred to the configuration memory. A comparator compares the first code value to the second code value to verify that the configuration data was not corrupted during the transfer from the non-volatile memory to the configuration memory.

Abstract: In one embodiment, an integrated circuit (IC) such as a programmable logic device includes a plurality of IC input terminals and an input buffer having a buffer input terminal and a buffer output terminal. A multiplexer is adapted to selectively couple an IC input terminal to the buffer input terminal or to couple the buffer output terminal to the buffer input terminal.

Abstract: In one embodiment, an integrated circuit, such as an FPGA, has one or more programmable termination schemes, each having a plurality of resistive termination legs connected in parallel, and a calibration circuit designed to control each termination scheme for process, voltage, and temperature (PVT) variations. A sense element in the calibration circuit and each resistive leg in each termination scheme has a transistor-based transmission gate connected in series with a non-silicided poly (NSP) resistor. The negative temperature coefficient of resistivity of each NSP resistor offsets the positive temperature coefficient of resistivity of the corresponding transmission gate to provide a temperature-independent sense element and temperature-independent termination legs. The temperature-independence and constant IV characteristic of the sense element and termination legs enable a single calibration circuit to simultaneously control multiple termination schemes operating at different termination voltage levels.

Abstract: In one embodiment, a programmable logic device includes a first multiplexer; a first memory adapted to store an identification code of the programmable logic device; and a second memory adapted to store an identification code of the programmable logic device. Inputs of a second multiplexer are coupled to the first memory and the second memory, and an output of the multiplexer is coupled to an input of the first multiplexer. The second multiplexer is adapted to select between the identification code stored in the first memory and the identification code stored in the second memory to provide the selected identification code to the first multiplexer.

Abstract: An apparatus for generating round-key words in accordance with a Rijndael algorithm. In one embodiment of the invention, the apparatus includes (a) a key expansion register block, having a key expansion register adapted to receive a final cipher key of a key expansion schedule in accordance with the Rijndael algorithm; (b) a round constant generator; (c) a first XOR adder adapted to add a first word of the key expansion register to a second word to generate and provide a first sum to the key expansion register block; (d) a transformation block adapted to generate a transformed word based on the first sum and the current round constant over four counts of a first cyclical counter; and (e) a second XOR adder adapted to add the transformed word to the first word of the key expansion register to generate and provide a second sum to the key expansion register block.

Abstract: In one embodiment, a programmable logic device includes a plurality of programmable logic blocks and a plurality of slices within each of the programmable logic blocks. At least one programmable logic blocks includes a first slice not adapted to provide register functionality or RAM functionality, a second slice adapted to provide register functionality but not RAM functionality, and a third slice adapted to provide register functionality and RAM functionality. Control logic within the programmable logic block is adapted to provide control signals at the programmable block level and at the slice level.

Abstract: In one embodiment of the invention, programmable circuits, such as FPGAs, may be used to implement different types of functions, such as a multi-bit adder, using look-up table (LUT) circuits as their building blocks. Efficient generation of carry-out signals and fast-carry generation signals using available SRAM cells in the various embodiments of the LUT circuit can reduce and/or eliminate area-inefficient look-ahead carry logic without a significant delay in signal generation.

Abstract: Systems and methods are disclosed herein to provide test features for integrated circuits. For example, in accordance with an embodiment of the present invention, an integrated circuit includes an input signal path adapted to route an address signal for a configurable memory. An input multiplexer, coupled to the input signal path, is controllable to route a first test signal provided via the input signal path for at least one memory configuration that does not use the input signal path for the address signal.

Abstract: Various techniques are provided to selectively collapse connections. In one example, a computer readable medium includes a computer program for performing a method of selectively collapsing connections between a plurality of LUTs. The method includes performing a first timing analysis to determine a timing slack value for each connection and determine a number of timing paths using each connection. The method also includes calculating a weight for each connection based on at least the timing slack value and the number of timing paths. The method further includes comparing the connections associated with a first one weight interval with collapsing criteria, wherein the first weight interval includes weights larger than weights of the remaining weight intervals. The method also includes collapsing the connections associated with the first weight interval that satisfy the collapsing criteria, and selectively repeating the comparing and collapsing for connections associated with remaining weight intervals.

Abstract: Systems and methods are disclosed herein to provide improved security key techniques for programmable logic devices. For example, in accordance with an embodiment of the present invention, a method of providing data security for a programmable logic device (PLD) includes programming a plurality of programmable fuses that stores a security key comprising a plurality of data bit values, wherein each data bit value is associated with a respective subset of at least three of the fuses. The security key is retrieved from the fuses using the data bit values stored by each subset of the fuses. An encrypted configuration data bitstream is decrypted using the retrieved security key to obtain an original configuration data bitstream to configure the PLD.

Abstract: In one embodiment of the invention, a programmable logic device includes a plurality of programmable logic blocks and a plurality of dual-slice logic blocks within a programmable logic block. A dual-slice logic block includes a first slice including at least two lookup tables (LUTs); a second slice including at least two LUTs; and a routing circuit coupled to each of the LUTs within the first and second slices. The routing circuit is adapted to share outputs of the dual-slice logic block among the LUTs. In another embodiment of the invention, the dual-slice logic block includes a second routing circuit coupled to each of the LUTs within the first and second slices. The second routing circuit is adapted to share inputs of the dual-slice logic block among the LUTs.

Abstract: An on-chip temperature sensor for an integrated circuit includes in one embodiment a voltage/current source circuit that provides a reference voltage and a current. A sense signal circuit receives the current of the voltage/current source circuit and provides a sense signal corresponding to the temperature of the integrated circuit. A reference signal receives the reference voltage of the voltage/current source circuit and provides a reference signal having a selectable value. A comparator compares the sense signal of the sense signal circuit to the selectable reference signal of the reference signal circuit and provides a temperature sensor output signal.

Abstract: Systems and methods are disclosed herein to provide improved clock, delay, and skew techniques. For example, in accordance with an embodiment of the present invention, an integrated circuit includes a clock generator to provide a bias signal and a clock signal, with control logic providing a delay control signal based on the bias signal and a multi-bit control signal. A clock skew circuit provides a delay to the clock signal based on the delay control signal provided by the control signal. Memory coupled to the control logic provides the multi-bit control signal.

Abstract: A programmable logic device, in accordance with an embodiment of the present invention, includes a plurality of multiplexers, having fuse input terminals and input signal terminals, and a plurality of associated fuses providing fuse signals to the fuse input terminals to control selection of the input signal terminals. The fuses in a first state select a first input signal terminal of the input signal terminals, with a first multiplexer from the plurality of multiplexers receiving a first logic level signal at the first input signal terminal and providing the first logic level signal to the first input signal terminal of a first set of the plurality of multiplexers. The fuses associated with the first set are adapted to be programmed before the fuses associated with the first multiplexer.

Abstract: In one embodiment of the invention, a clock distribution (CD) chip has one or more input pins, input buffer circuitry, clock generation and distribution circuitry, fanout circuitry, one or more output pins, a feedback pin, and feedback buffer circuitry. Based on single-ended or differential input clock signals applied to the input pins, the CD chip can be programmably configured to generate zero, one, or more zero-delay (ZD) output clock signals and zero, one, or more non-zero-delay (NZD) output clock signals for simultaneous presentation at the output pins.

Abstract: In one embodiment of the invention, a programmable logic device includes a plurality of programmable resources; non-volatile configuration memory adapted to store configuration data for configuring the plurality of programmable resources; a register adapted to load configuration data into the non-volatile configuration memory; and test circuitry coupled to the register. The test circuitry is adapted to configure a programmable resource with test data stored in the register rather than with configuration data stored in the non-volatile configuration memory. In another embodiment of the invention, the programmable logic device includes a buffer coupled between the configuration memory and a programmable resource, and the test circuitry includes a logic circuit coupled between the register, the configuration memory, and the buffer. The logic circuit is responsive to a test mode signal to route test data from the register to the buffer.

Abstract: Improved reconfiguration techniques are provided for programmable logic devices (PLDs). For example, in accordance with an embodiment of the present invention, a programmable logic device includes logic blocks, input/output blocks and corresponding input/output pins, and configuration memory. The PLD also includes registers adapted to capture output signal values of the input/output pins before a reconfiguration of the programmable logic device and to provide the captured values on the input/output pins during the reconfiguration of the PLD.

Abstract: Techniques are described to monitor charging of an integrated circuit during manufacturing processes. In one example, an integrated circuit includes first and second pads adapted to be charged by charge carriers during manufacture of the integrated circuit. The integrated circuit also includes a reference nonvolatile memory cell comprising a floating gate and a control gate, wherein the control gate is coupled to the first pad. The integrated circuit further includes a charging protection device coupled to the control gate of the reference memory cell and adapted to limit the gate voltage of the control gate induced by the charge carriers. In addition, the integrated circuit includes a charging monitor nonvolatile memory cell comprising a floating gate and a control gate, wherein the control gate is coupled to the second pad but not to a charging protection device adapted to limit the gate voltage of the control gate.

Abstract: Systems and methods disclosed herein provide temperature monitoring within an integrated circuit. For example, in accordance with an embodiment of the present invention, a bandgap reference circuit provides a reference voltage; a constant current generator provides a constant current; and a reference signal circuit receives the reference voltage and provides a reference signal having a selectable value based on the reference voltage. A bipolar diode receives the constant current and provides a sense signal, with a value of the sense signal corresponding approximately to a temperature value of the integrated circuit. A comparator receives the sense signal and the reference signal and provides a temperature sensor output signal.

Abstract: Various techniques are disclosed herein to provide an improved approach to the loading of configuration data into configuration memory of programmable logic devices. For example, in accordance with one embodiment of the present invention a method of configuring a programmable logic device includes reading a first bitstream from a first memory block of an external memory device. The first bitstream is checked for errors and a second bitstream is read from a second memory block of the external memory device if an error is detected. Configuration memory of the programmable logic device is programmed with configuration data provided in one of the first bitstream and the second bitstream.