Abstract: Within a high level modeling system (HLMS), a method of visualizing a circuit design can include identifying the circuit design and reading hardware cost information for the circuit design. The method also can include presenting a graphical representation of the circuit design having at least one visual characteristic which can be varied according to the hardware cost information.

Abstract: A computer-implemented method of scheduling a multi-rate, synchronous circuit design for simulation within a high-level modeling system. The method can include determining a component clocking rate for each of a plurality of synchronous components of the circuit design and classifying each of the plurality of synchronous components into a plurality of schedules according to component clocking rate. For each clock cycle during simulation, the method can include selecting one of the plurality of schedules and executing each synchronous component of the selected schedule. A value determined through execution of a synchronous component of the circuit design can be output.

Abstract: A method of communicating data among a plurality of software modules of a heterogeneous software system can include constructing an XTable object in a first software module of the plurality of software modules and providing the XTable object to a second software module of the plurality of software modules. The method further can include extracting data from the XTable object within the second software module.

Abstract: An Add-Compare-Select circuit for use with a trellis decoder can include a first module and a second module. The first module can provide a difference signal specifying an indication of a difference between a second path cost and a first path cost of a trellis. The second path cost can be a sum of a second state cost and a second branch metric and the first path cost can be a sum of a first state cost and a first branch metric. The second module can select the first path cost or the second path cost as a new cost according to the difference signal of the first module.

Abstract: A method of creating a design-specific I/O model document can include reading a plurality of I/O pin models corresponding to available I/O pin profiles on a target device (355) and identifying I/O pins of the target device that are used by a circuit design (325). An I/O pin profile for each I/O pin of the target device that is used by the circuit design can be determined (345). An I/O pin model can be selected from the plurality of I/O pin models for each I/O pin of the target device that is used by the circuit design according to the I/O pin profiles (355). The design-specific I/O model document for the circuit design can be generated by including each selected I/O pin model within the design-specific I/O model document (365). The design-specific I/O model document can be output (380).

Abstract: A method of partitioning a design across a plurality of integrated circuits can include creating a software construct for each one of the plurality of integrated circuits and assigning a plurality of instances to a selected software construct. Each of the plurality of instances can be from a different logic hierarchy. The method further can include automatically adding at least one input/output buffer and port to the selected software construct to accommodate the plurality of instances and creating nets connecting the plurality of instances and the at least one input/output buffer and port within the selected software construct.

Abstract: A computer-implemented method of incorporating probe points within a circuit design for implementation within an integrated circuit device can include routing probe nets of the circuit design in an overlap mode, identifying a plurality of probe net routes including a common overlapping portion, and including a switch at each location within the circuit design where at least two probe net routes of the plurality of probe net routes diverge from a common point. The circuit design can be output.

Abstract: A method of estimating jitter for a DFS can include determining a plurality of linear equations, wherein each linear equation corresponds to, at least in part, a combination of multiplier and divisor attributes for setting an output frequency of the DFS, identifying maximum and minimum values for the slope component and the vertical axis intercept component from the plurality of linear equations, providing an equation for determining minimum jitter given, at least in part, an input frequency, and providing an equation for determining maximum jitter given, at least in part, an input frequency. A linear equation can be derived for estimating jitter of the DFS according to a specified input frequency and a specified value of the divisor attribute of the DFS. The linear equation further can depend upon the minimum jitter and the maximum jitter.

Abstract: A method of implementing a circuit design for a target device can include assigning load pins of a high fanout signal of a placed circuit design into a plurality of windows according to a location of each load pin on the target device. A source of the high fanout signal can be replicated, wherein each window is associated with a source of the high fanout signal. For each source of the high fanout signal, the source can be connected to load pins of the window associated with the source and the source can be placed within the window associated with the source. The placed circuit design can be output.

Abstract: A system for signal level shifting in an IC can include a first inverter having a first pull-up device and a pull-down device, wherein the first inverter is operable to receive an input signal having a voltage potential at a logic high that does not disable the first pull-up device. The system can include a second inverter coupled in series to an output of the first inverter, and a control module coupled to the output of the first inverter and an output of the second inverter. Prior to the input signal transitioning to the logic high, the control module is operable to decouple the input signal from the first pull-up device, disable the first pull-up device, and close a feedback loop that latches an output state of the second inverter.

Abstract: A computer-implemented method of performing timing analysis upon a circuit design having synchronous circuit elements can include selecting a destination pin having a plurality of source pins, wherein each source pin of the plurality of source pins defines a data path to the destination pin. A slack of a selected path of the data paths to the destination pin can be determined. A timing adjustment of each of the plurality of source pins can be compared to the slack of the selected path, wherein each timing adjustment is determined using static timing analysis. A simulation node can be selectively included within the circuit design according to the comparison. The circuit design can be output.

Abstract: A method of determining validity of slice packing for a programmable device can include identifying a slice topology for a slice, identifying a circuit fragment assigned to the slice, and generating a set of Boolean equations describing conditions for mapping the circuit fragment to the slice according to the slice topology. The method further can include determining whether a solution to the set of Boolean equations exists and indicating whether the slice is validly packed according to whether a solution for the set of Boolean equations is determined.

Abstract: A method of profiling a hardware system can include compiling a high level language program into an assembly language representation of the hardware system and translating instructions of the assembly language representation of the hardware system into a plurality of executable, software models. The models can be implemented using a high level modeling language for use with cycle accurate emulation. The method also can include instrumenting at least one of the plurality of models with code that, when executed, provides operating state information relating to the model as output and indicating expected behavior of the circuit by executing the models in an emulation environment.

Abstract: A computer-implemented method of technology mapping a circuit design for implementation within a programmable logic device can include determining a plurality of cut sets for the circuit design, wherein each cut set includes a plurality of cuts. The method can include evaluating each cut set according to a cost function that depends, at least in part, upon a measure of inter-cut symmetry and selecting a cut set according to the cost function. Each cut of the selected cut set can represent an instantiation of at least one logic component within the programmable logic device. The circuit design specifying the selected cut set can be output.

Abstract: A method of protecting a circuit design implemented within an integrated circuit (IC) from electrostatic discharge (ESD) can include positioning a device array pair comprising first and second device arrays on the IC to share a common centroid, wherein the first and second device arrays are matched. An ESD diode array pair comprising first and second ESD diode arrays can be positioned on the IC adjacent to a first perimeter encompassing the first and second device arrays, wherein the first and second ESD diode arrays share the common centroid and are matched. A cathode terminal of each ESD diode of the first ESD diode array can be coupled to an input of the first device array, and a cathode terminal of each ESD diode of the second ESD diode array can be coupled to an input of the second device array.

Abstract: A method of managing correlation data for a design implementation process can include identifying correlation data from each of a plurality of design applications. Each of the design applications can generate a circuit description and the correlation data can specify associations between circuit elements of different ones of the circuit descriptions. The method also can include storing the circuit descriptions and the correlation data independently of one another and determining a relationship among circuit elements of the circuit descriptions according to the correlation data.

Abstract: A method of passing data among modules of a heterogeneous software system can include identifying a scripted function to be executed within the heterogeneous software system and building a wrapper script by embedding a call to the scripted function and an XTable object associated with the scripted function within the wrapper script. The method further can include executing the wrapper script thereby causing the scripted function to execute and receiving a result from execution of the scripted function.

Abstract: A method of evaluating a design under test (DUT) can include executing a testbench involving the DUT and, during execution of the testbench, estimating an amount of time needed to perform a first transaction with the device under test according to resolved variables. The method also can include setting a timer with the estimated amount of time needed to perform the first transaction and invoking the first transaction with the device under test. Responsive to expiration of the timer, an indication as to whether the first transaction completed execution can be provided.

Abstract: A computer-implemented method of verifying electrical isolation of portions of a circuit design for a programmable integrated circuit (IC) can include translating a circuit design into a circuit design bitstream specifying a plurality of regions, wherein the regions are to be isolated from one another. Routing resources of the programmable IC that are not used by the circuit design can be identified. A fence bitstream can be generated that specifies the unused routing resources. The circuit design bitstream can be compared with the fence bitstream. An indication of whether the plurality of regions of the programmable IC are isolated can be output according to the comparison.

Abstract: A computer-implemented method of balancing logic resource usage in a circuit design for a programmable integrated circuit (IC) includes determining that an assignment of elements of the circuit design to a first type of logic resource is unbalanced compared to an assignment of elements to an alternate type of logic resource. Binary variables are defined for circuit elements assigned to the first and alternate types of logic resources, where each binary variable indicates whether the associated circuit element is to be re-assigned to the first or alternate type of logic resource. Constraints are defined specifying relationships among selected variables. Values for the variables are obtained according to the constraints by minimizing a function dependent on a sum of the binary variables. Circuit elements are re-assigned to the first or alternate types of logic resources according to the values determined for the binary variables, and the circuit design is output.