Simulator Configuration Guide for Synopsys Models

Chapter 7: Using QuickSim II with Synopsys ModelsSimulator Configuration GuideTo select Shell Software timing every time you invoke QuickSim II with a particulardesign, you can create or edit a quicksim.startup file under the design viewpoint. Addthe following line to the file to directly call the function that implements this SignalInstance command:$signal_instances("lst", "all", "/I$1");Substitute the instance name of any hardware modeled device for /I$1.You can also use the actual measured delays from the device as an alternative timingoption with hardware models. For more information about this feature, refer to “TimingMeasurement” on page 182.Performance MonitoringYou can monitor the performance of the hardware modeler and append the results to thesimulator log file after simulation. To enable performance monitoring, in the windowwhere you are running the simulator, enter the following:% setenv LM_OPTION “monitor_performance”For more information, refer to “Performance Monitoring” in the ModelSource User’sManual.Unknown Handling and PropagationThe unknown handling and propagation commands enable you to modify the hardwaremodeling system’s default handling of device input and I/O pins that the simulator setsto unknown.Unknown MappingSince the hardware modeling system cannot present an unknown logic level to aphysical device, unknown values presented to inputs of hardware models must bemapped to known values. The SIGnal INSTance xp, x0, x1, and xz commands mapunknowns for all instances of the selected components to the previous state, logic zero,logic one, or high-impedance (float), respectively. By default, unknowns are mapped tothe previous state. Unknowns mapped to high-impedance are also mapped to theprevious state.You can customize unknown handling per pin by using the -p pin_name argument. Forexample, you can issue the following:sig inst x0sig inst x1 -p clk1These commands map all unknowns for the selected components—except for unknownsreceived on the clk1 pin—to logic zero (0). Any unknowns received on clk1 are mappedto logic one (1).180 Synopsys, Inc. October 6, 2003