Abstract: In accordance with the present invention there is provided a method for determining an optimized parameter for a circuit simulation. A circuit path for the simulation is determined, and maximum and minimum optimization parameters are decided. Next, the circuit path is simulated using the maximum optimization parameter. The circuit path is simulated using the minimum optimization parameter and a primary criteria parameter is also calculated. The simulations are compared to determine whether the same status (both succeed or both fail) is generated for both the minimum optimization parameter and the maximum optimization parameter. If the simulations do not indicate the same status, then the optimization parameter is recalculated and the circuit is simulated until the primary criteria parameter converges to a prescribed value.

Abstract: In a first aspect, a first method of creating a programmable link delay during cycle simulation of a system is provided. The first method includes the steps of (1) modeling a system for cycle simulation, wherein the system includes (a) a plurality of links; (b) link transmitting logic adapted to transmit data on the plurality of links; (c) link receiving logic adapted to receive data from the plurality of links; and (d) link training logic coupled to the link receiving logic and adapted to compensate for skew between links; and (2) employing delay logic, coupled to the plurality of links, in the modeled system to create a known skew between links during cycle simulation. Numerous other aspects are provided.

Abstract: This solution uses a statistical characterization of the transaction to predict the total effect on response time of each network component.

Abstract: The operating characteristic of a transistor, modeled by a resistive element having fixed resistance and a power source voltage that varies with time, is segmented into a linearity region in which a current increases as a gate potential varies and a saturation region in which the current gradually decreases as the gate potential remains at a constant level, so that gradual decrease in current in a saturation region of the transistor is properly reflected and a delay time is estimated in a precise manner.

Abstract: A translator tool for translating simulation test data generated to test clock recovery circuitry of a device from an event-based format to a cycle-based format readable by integrated circuit testers is presented. The simulation test data includes test timing irregularities intentionally injected into a serial data signal that will be processed by the clock recovery circuitry of the device under test. The translator tool includes a normalization function that extracts the intentionally injected timing irregularities from the event-based test data and generates corresponding normalized event-based test data without the extracted timing irregularities. The translator tool includes a cyclization engine that cyclizes the normalized event-based test data to generate corresponding cycle-based test data without the timing irregularities.

Abstract: A method of determining the critical path of a circuit includes first determining the paths, their mean path transit times and their path transit time fluctuations. Paths having similar statistical parameters are combined to form one path group. For each path group, a statistical group figure is, then, calculated and, for the totality of paths considered, a statistical total figure is calculated. Finally, the critical paths of the circuit are determined by taking into consideration the total figure, comparing the group figures at or above a critical path transit time Tc.

Abstract: Methods and apparatus for hardware scheduling processes handling are presented. The apparatus includes a table of task lists. Each task list has specifications of processes requiring handling during a corresponding time interval. Each task list is parsed by a scheduler during a corresponding interval and the processes specified therein are handled. The methods of process handling may include a determination of a next time interval in which the process requires handling and inserting of process specifications in task lists corresponding to the determined next handling times. Implementations are also presented in which task lists specify work units requiring handling during corresponding time intervals. The entire processing power of the scheduler is used to schedule processes for handling. Advantages are derived from an efficient use of the processing power of the scheduler as the number of processes is increased.

Abstract: A debugger produces a display based on instructions executed by a circuit simulator or verification tool and on waveform data produced by the simulator or verification tool when executing the instructions. The instructions include a set of statements, each corresponding to a separate circuit signal generated by a circuit and each including a function defining a value of the circuit signal as a function of values of other circuit signals. The simulator evaluates the statements at various simulation times to compute signal values at those simulation times. The waveform data indicates signal values the simulator computes when evaluating the statements. The debugger display includes a set of statement event symbols, each corresponding to a separate evaluation of a statement and each positioned in the display to indicate a simulation time at which the simulator evaluated the statement.

Abstract: Methods and apparatus are provided for design entry and synthesis of components, such as components implemented on a programmable chip. In one example, a design tool receives natural or intuitive parameters describing characteristics of a component in a design. Natural or intuitive parameters include input data rate, output latency, footprint, etc. Non-natural or non-intuitive parameters such as clock rate and pipeline stages need not be provided. The design tool automatically selects optimal components using natural parameters. Multiple instantiations of an optimal component, or multiplexing through an optimal component can be used to further improve the design.

Abstract: An emulation parameter indicative of a data processing operation performed by a data processor is exported from the data processor. The parameter value is provided as a plurality of digital bits. After determining that the bits of a first group within the plurality of bits all have the same bit value and that a predetermined bit within a second group of the plurality of bits has a bit value equal to the bit value of the bits of the first group, only the second group of bits is output from the data processor without outputting the first group of bits.

Abstract: A hardware/software co-simulation permits access to a server state from any process in the hardware/software co-simulation. In one embodiment, a co-simulation interface receives a request from a client system for configuration data for the server state in of the hardware/software co-simulation. The configuration data defines memory locations in the co-simulation from which the server state can be assembled. The interface inserts the request in the co-simulation. The co-simulation responds with the configuration information. Based on the configuration information, memory operations can be performed on the server state.

Abstract: An apparatus and a method for the synchronization of an asynchronous signal in synthesis and simulation of a clocked circuit are disclosed, in which a circuit to be simulated and tested is described with a hardware description language and the asynchronous signals present therein are marked. For producing a network list, the hardware description language is processed with a synthesis tool, in which a specific synchronization module is inserted at every marking. For testing the time behavior of the signals in the clocked circuit on the basis of the network list, a simulator implements a logic/timing simulation, in which a test of the time behavior is selectively deactivated for each inserted synchronization module. The unknown statusses that still occur are output via a display.

Abstract: Apparatus for testing a system on a chip (SOC) comprises a first SOC including a first hard disk controller and a first read channel. A second SOC comprises a second hard disk controller and a second read channel. An arbitrary waveform generator (AWG) generates a timing signal. An adder is provided in communication with the arbitrary waveform generator. The first SOC differentiates the timing signal received from the arbitrary waveform generator and generates a write signal in synchronization with the timing signal. The adder adds the write signal from the first SOC and the timing signal to output a combined signal having a timing signal component and a write signal component. The second SOC differentiates the timing signal component which simulates a servo signal and the write signal component simulates a signal being accessed by a read channel.

Abstract: A method and system for reducing the time required for execution of the dynamic timing simulation for a logic simulator. For a logic circuit simulator having a compilation phase and a runtime phase, a delay assessment is performed during the compilation phase in order to identify storage elements that are exempt from possible timing violations at runtime. The runtime timing checks are removed from the exempt storage elements, thereby reducing the runtime calculation effort. Additionally, combinational portions of the circuit that drive the exempt storage elements are examined for element delays that can be effectively eliminated (e.g., zero delayed) from the runtime calculations, thereby providing a further reduction in the computational overhead via the use of cycle based simulation for these.

Abstract: Method and apparatus for determining delay of a circuit. A clock signal is provided to a variable delay and then to the circuit. The clock signal obtained from the circuit is provided to a data register, such as a flip-flop, as a clock input. The clock signal is provided to the flip-flop as a data input. Output of the data register is provided to a controller to incrementally adjust phase shift until the data input and clock input are substantially aligned in phase. All incremental adjustments in phase shift are counted to provide an indication of delay of the circuit.

Abstract: A system designed, including commercially distributed modules protected as intellectual property (IP), is verified in a manner that the IP provider and the user communicate with each other over a communication line to complete the system design verification. A system verification equipment to be operated by the IP provider receives from the system designer across the communication line an input vector at time n to a module provided to the system designer who designed the system integrated using one or more provided IP modules. After simulating the module operation with the input vector, the verification equipment returns an output vector obtained at time n+1 to the system designer over the communication line. The verification equipment examines the input vectors to the provided IP modules and records statistics information thereof, based on which the provider will quantitatively understand how the provided modules have been used.

Abstract: Applications software can be rapidly tested and developed for a multi-processor chip even though the hardware of new processors of the multi-processor chip is not yet available. This can be accomplished by executing software simulations of the new processor designs and corresponding applications software either on a previously designed processor that is hardware on the multi-processor chip or on a workstation development platform. The execution of the previously designed processor is typically much faster than the execution on a simulator running on a personal workstation development platform, and therefore the execution time is quicker. Furthermore, the processor simulation and application software can be configured to take advantage of the platform most appropriate for execution and avoid simulation of portions of the new processors that are not necessary for testing the applications software.

Abstract: A method and apparatus for identifying potential noise failures in an integrated circuit design is described. In one embodiment, the method comprises locating a victim net and an aggressor within the integrated circuit design, modeling the victim net using two ?-type resistor-capacitor (RC) circuits, including determining a coupling between the victim net and the aggressor, and indicating that the integrated circuit design requires modification if modeling the victim net indicates that a potential noise failure may occur in the integrated circuit design.

Abstract: A design tool and method characterizes a circuit at a hardware level description. A behavioral level description of the circuit is created. Symbolic equations for components of the behavioral level description are created. The behavioral level description is partitioned by inserting a marker component into the behavioral level description of the circuit to simplify subsequent processing used to prove equivalence between the behavioral and hardware level descriptions. The symbolic equations are back-substituted until output variables are expressed in terms of input variables that determine the output variables. The marker component is defined using a unique symbolic name. Current time counts of each clock cycle are used to compute an index for the marker component. The behavioral level description is transformed to produce symbolic and numeric files for compilation to gates and proof of functionality.

Abstract: The present invention describes a method and an apparatus for determining switching power consumption of global devices (e.g., repeaters, flops or the like) in an integrated circuit design during high-level design phase after the global routing for the integrated circuit is available. The clock cycle is divided into various timing intervals and the timing reports are generated for each cycle to determine a time-domain staggered distribution of each device's switching activity within a given timing interval. Each device's switching activity is analyzed within the given timing interval (or segment thereof). The power consumption is determined for each device that switches in the given timing interval.

Abstract: An apparatus comprising one or more groups of boundary scan cells, one or more group buffers, one or more repeater buffers and a controller. The group buffers may be coupled to each of the groups of boundary scan cells. The repeater buffers may be coupled in series with the group buffers. The controller may be coupled to the groups of boundary scan cells through the group buffers and the repeater buffers. The apparatus may be configured to buffer the groups of boundary scan cells to reflect an order of I/Os around the apparatus.

Abstract: A method and a corresponding apparatus for verifying a minimal level sensitive timing abstraction model provides for an extension of the timing abstraction model. The method modifies and runs the timing abstraction model with certain stimulus to establish whether the timing results with the timing abstraction model are identical to the timing result with the modeled circuit. The timing abstraction model extension, which enables verification of the timing abstraction model, only negligibly increases the size of the timing abstraction model, thus keeping STA runtimes short and the memory requirements small.

Abstract: A time simulation technique for determining the service availability (or unavailability) of end-to-end network connections (or paths) between source and sink nodes is disclosed. The failure could be either a single failure mode or a multiple failure mode. The time simulation apparatus includes a network representation having pluralities of nodes, links and connections; each plurality having various attributes such as relating to failure, recovery and repair mechanisms. The apparatus further includes a mechanism for selecting one instance from each of the pluralities of nodes, links and connections based on the attributes; a failure/repair module for performing a simulated failure and repair on the selected instances as appropriate; a mechanism for selecting a connection between source and sink nodes; and an arithmetic mechanism for calculating availability of the selected connection.

Abstract: The disclosed design verification system includes a verification engine to model the operation of an integrated circuit and to assess the model's adherence to a property during N time steps of its operation. The value of N is recorded and propagated. The propagated value of N is used to reduce resources expended during subsequent analysis of the integrated circuit by ignoring the model's adherence to the property during the early stages of subsequent analysis (during time steps less than N). The system may include a diameter estimator that identifies a value of N beyond which subsequent modeling of the integrated circuit produces no new states. Property checking is ignored during states having a time step value greater than the estimated diameter.

Abstract: A significant improvement over current methods for co-simulation of the hardware and software components of embedded digital system designs is provided. The present invention integrates the hardware and software components of a system design into a single unified simulation environment. The unified simulation environment and the various component models of the system design are created in a high level general purpose programming language. This allows inter-component communications and communications with the unified simulation environment to be carried out through the use of function calls, which significantly increases the overall simulation speed. Additionally, the unified simulation environment runs as a single process, which significantly improves debugging capabilities.

Abstract: An emulation controller (12) located externally of an integrated circuit (14) can be provided with timing information indicative of operation of an internal clock of the integrated circuit that drives internal data processing activity of the integrated circuit. In response to each cycle of the internal clock, a corresponding digital bit is produced to represent the internal clock cycle, and the digital bits are output to the emulation controller at an output clock rate that differs from the clock rate of the internal clock.

Abstract: The invention relates to a method for modeling an input/output cell located on the perimeter of an integrated circuit. A method is taught to model an the integrated circuit when sufficient area is not available on the perimeter of the integrated circuit. The input/output cell can be modeled in two locations; one location on the perimeter of the cell and a second location in the interior area, or core, of the integrated circuit. The model uses a cover to prevent the area of the core of the integrated circuit from being used for other purposes. When the input/output cell is divided into a main cell and more than one pre-cell, the model uses a cover for each pre-cell. The model adjusts the timing of the signals to compensate for the input/output cell being divided into two areas. In an embodiment a software tool performs the functions of the model.

Abstract: In an illustrative embodiment, a desired signal processing transfer function is implemented using a generic pipelined data processor having variable latency followed by a variable latency multistage FIFO. The delay of the multistage FIFO is varied dynamically to keep the number of outstanding samples (and thus the overall latency) a constant. The present invention enables an abstract approach to the design of higher-level signal processing transfer functions while the design of the underlying low-level circuitry is driven solely by target implementation technology issues. Thus, the higher-level design of signal processing transfer functions is decoupled from the low-level (logic and physical) design. Furthermore, test bench modules and vectors for testing the transfer function can also be to be prepared independent of the specifics of the low-level circuitry associated with the target implementation technology.

Abstract: A method and system for accurately validating performance and functionality of a processor in a timely manner is provided. First, a program is executed on a high level simulator of the processor. Next, a plurality of checkpoints are established. Then, state data at each of the checkpoints is saved. Finally, the program is run on a plurality of low level simulators of the processor in parallel, where each of the low level simulators is started at a corresponding checkpoint with corresponding state data associated with the corresponding checkpoint.

Abstract: To calculate pin-to-pin delay time, which is delay time from the input pin to the output pin of a logic block, and block-to-block delay time, which is delay time from an output pin of one block to an input pin of the next block, firstly, the pin-to-pin delay time and the block-to-block delay time are calculated with negligence in aging caused by a hot carrier effect, secondly, degradations caused by aged transistors connected to the input pin and the output pin, and lastly, the pin-to-pin delay time and block-to-block delay time are modified by the degradation rate.

Abstract: A netlist model of a physical circuit is provided. The netlist model includes a virtual delay element, wherein the virtual delay element is coupled to an asynchronous circuit element.

Abstract: A method of discriminating between different types of simulated scan failures includes simulating a scan enable signal to a circuit represented by a netlist corresponding to a scan chain coupled to combinatorial logic being tested, simulating initiation of a data capture cycle in the netlist corresponding to the scan chain, the data capture cycle simulating a series of scan flops from the scan chain being simulated together with the combinatorial logic and simulating scanning data out from each flop in the scan chain and into a test program. The test program extracts the simulated scan flops and graphically displays the simulated scan flops versus time.

Abstract: A method for determining an interconnect delay at a node in an interconnect having a plurality of nodes. The method includes performing a bottom-up tree traversal to compute the first three admittance moments for each of the nodes in the interconnect. The computed admittance moments are utilized, in an advantageous embodiment, to compute a pi-model of the downstream load. Next, the equivalent effective capacitance value Ceff is computed utilizing the components of the computed pi-model and the Elmore delay at the node under evaluation. In an advantageous embodiment, Ceff is characterized by: Ceff=Cfj(1?e?T/?dj) where Cfj is the far-end capacitance of the pi-model at the node, T is the Elmore delay at the node and ?dj is the resistance of the pi-model (Rdj) multiplied by Cfj. The interconnect delay at the node is then determined utilizing an effective capacitance metric (ECM) delay model.

Abstract: Complex distributed systems with basic components (B) which have data processing program modules and/or electronic circuit modules that exchange data with each other have their timing behavior analyzed based on the timing behavior of individual basic components (B) and transformation functions derived from event model classes.

Abstract: Simulation methods and simulators are presented which operate on a computer under software control. Said computer simulation methods and simulators are specially suited for simulating digital circuits and mixed analog digital circuits. The methods enable efficient simulation, meaning resulting in a fast simulation while still obtaining accurate results. With fast simulation is meant that the simulation can be completed in a short simulation time. Accurate means that the signals obtained or determined by simulation are good approximations of the signals that would be measured when the circuit, which representation is under simulation, is actually running in real world. Indeed the simulation methods and the related simulation apparatus or simulator exploits a representation of a circuit.

Abstract: A method and apparatus for simulating multiple stimuli using symbolic encoding. In one embodiment, the method comprises encoding a plurality of sets of stimulus to create a symbolic stimulus, symbolically simulating a device under test, including applying the symbolic stimulus to the device under test, and outputting a symbolic result from the device under test in response to the symbolic stimulus.

Abstract: A method and apparatus for optimizing clock distribution in a circuit to reduce the effect of power supply noise. Parameters are determined including: a response curve of a power source for a circuit, a delay sensitivity of a clock net in the circuit to the power source, a delay sensitivity of a data net in the circuit to the power source, a data delay for the data net, and a clock delay for the clock net. The clock delay is adjusted to reduce the effect of power supply noise on the data net. The adjusting is based on the response curve of the power source, the delay sensitivity of the clock net, the delay sensitivity of the data net, the data delay, and the clock delay. The adjusting includes adding a pre-distribution clock delay.

Abstract: According to one embodiment, a method for isolating degradation mechanisms in transistors includes providing a ring oscillator having a plurality of delay elements. Each delay element operates as a delay element through the use of one or more transistors of only a first type and no transistors of the opposite type. The method further includes operating the ring oscillator and measuring the frequency resulting from the ring oscillator over time. The magnitude of an isolated degradation mechanism is determined based on a comparison of the measured frequency and an expected frequency for the ring oscillator absent degradation.

Abstract: A method and apparatus for clock generation and distribution in an emulation system is described. The present invention provides a method and apparatus for generating a derived clock signal with a circuit having a look up table. A counter circuit counts clock cycles and provides an index into the look up table. A frequency divider circuit may be used between the counter circuit and a base clock signal to provide an intermediate clock signal with a frequency that is less than the frequency of the base clock signal. In one embodiment, a selection circuit is provided to select between the base clock signal and an external clock signal.

Abstract: A method of and an apparatus for designing a test environment and of evaluating performance of the test environment and an electronic device during testing of the electronic device. A virtual test environment is created emulating an actual test environment. A virtual device emulating the actual electronic device is implanted into the virtual test environment, and that virtual device is stimulated with an input test signal emulating the actual input signal applied to the actual electronic device in the actual test environment. The integrity of the input test signal and the resulting output signal is evaluated. An adjustment might be made to the virtual calibration of the virtual test environment and/or to the virtual device, or both, and the design of the actual device might be improved. The invention can be implemented on a properly programmed general purpose processing system or on a special purpose system.

Abstract: A method is described for reducing delays in an analogue simulation model of a hardware circuit. The method includes the steps of stimulating via an input an output of said analog model, said output and said input having a relatively high resistance therebetween and applying a pulse to a relatively low resistance, whereby when said pulse is applied to the relatively low resistance, the input is connected to said output via the relatively low resistance so that the time constant of the circuit is reduced.

Abstract: A device for simulating circuits is provided with an identifying system and a verifying system. The identifying system identifies a pair of wires in which two signals operate simultaneously within an appointed period and a pair of wires in which two signals do not operate almost simultaneously within the appointed period. The verifying system verifies actions of a circuit to be analyzed, under an assumption that the coupling capacitor between the pair of wires in which it is judged by the identifying system that two signals do not simultaneously operate within the appointed period is a ground capacitor.

Abstract: A method and system for visualizing circuit operation. In the method device activity is obtained based on one or more of measured or simulated activity. The device activity is expressed in a representation, and the expressed activity is represented in a visual form. One suitable form of activity is the simulated version of the PICA slow motion movie. The invention may apply to other simulated design data vies as well, such as switch level simulation, current density simulation, and power density simulation.

Abstract: A method of calculating delay for a process variation includes finding a value for each of exactly two independent variables that results in a maximum or minimum variation of estimated cell delay plus net delay, calculating a variation of resistance from the value found for each of the exactly two independent variables, calculating a variation of capacitance from the value found for each of the exactly two independent variables, adding the calculated variation of resistance to a net resistance to generate a modified net resistance for a selected net, adding the calculated variation of capacitance to a net capacitance to generate a modified net capacitance for the selected net, and calculating the cell delay plus net delay from the modified net resistance and the modified net capacitance.

Abstract: A method of verifying test data for testing an integrated circuit device having multiple device time domains includes selecting a virtual tester time domain and, if the cycle duration of the virtual tester time domain is equal to the cycle duration of one of the multiple device time domains, translating the test data for each device time domain other than that one time domain to the virtual tester time domain and otherwise translating the test data for each device time domain to the virtual tester time domain. The translated test data is then applied to a device logic simulator that simulates integrated circuit device.

Abstract: A technique is provided for use in computerized modeling of an electronic system. The technique bases simulation of the system's operation (e.g., timing operation) upon both actual physical characteristics of a part of the system, and hierarchical analysis-based models of the rest of the system.

Abstract: A program tool automatically generating interconnect logic for a system-on-a-chip is based on a library of operational cores and on a architecture which requires all data exchange between cores to proceed via shared memory, which may be ‘off-chip’. The architecture includes a data aggregation technique for access to memory with successive levels of arbitration.

Abstract: A software simulation technique for pipelined hardware is provided in which the hardware is modelled as a plurality of pipelined circuit element models that each respectively read their input data values from a first data storage area A and write their output data values to a second data storage area B. At the end of each simulated clock signal cycle, the first data storage area A and the second data storage area B are swapped to effectively replicate the behavior of the passing of signal values between pipelined stages in a hardware pipeline.

Abstract: A system and method for estimating interconnect delay are disclosed that include determining inductance of an interconnect. A transfer function is determined using the inductance, and two poles of the transfer function are determined. An interconnect delay is estimated using the two poles.

Abstract: A microcomputer includes a processor and an emulator interface circuit that provides processor state information to an external emulator. The emulator interface circuit operates at a clock speed that is lower than the clock speed of the processor and provides the state information at predetermined intervals, such as after a predetermined number of processor clock pulses. The state information may also be provided after a specified number of instruction fetches have occurred.