hspice book hspice ch03 1 Thu Jul 23 19 10 43 1998 Chapter 3 Specifying Simulation Input and Controls This chapter describes the structure and data flow in Star Hspice simulation the input requirements methods of entering data and Star Hspice statements used to enter input The chapter covers the following topics Examining the Simulation Structure Understanding the Data Flow Using the Star Hspice Command Using Standard Input Files Using Input Control Statements Setting Control Options Understanding the Library Types Understanding the Library Input Comparing the Control Options Default Values Star Hspice Manual Release 1998 2 3 1 hspice book hspice ch03 2 Thu Jul 23 19 10 43 1998 Examining the Simulation Structure Specifying Simulation Input and Controls Examining the Simulation Structure Figure 2 1 shows the program structure for simulation experiments Simulation Experiment Single point Analysis Initial Conditions Optimization Circuit Transient Sweep Analysis Results DC Statistical Worst Case Library Timing Violations Stimuli AC Options Figure 3 1 Simulation Program Structure Analysis and verification of complex designs are typically organized around a series of experiments These experiments are simple sweeps or more complex Monte Carlo optimization and setup and hold violation analyses that analyze DC AC and transient conditions For each simulation experiment tolerances and limits must be specified to achieve the desired goals such as optimizing or centering a design Common factors for each experiment are process voltage temperature and parasitics 3 2 Star Hspice Manual Release 1998 2 hspice book hspice ch03 3 Thu Jul 23 19 10 43 1998 Specifying Simulation Input and Controls Examining the Simulation Structure Two terms are used to describe experimental methods using Star Hspice Single point a single point experiment is a simple procedure that produces a single result or a single set of output data Multipoint an analysis single point sweep is performed for each value in an outer loop multipoint sweep The following are examples of multipoint experiments Process variation Monte Carlo or worst case model parameter variation Element variation Monte Carlo or element parameter sweeps Voltage variation VCC VDD and substrate supply variation Temperature variation design temperature sensitivity Timing analysis basic timing jitter and signal integrity analysis Parameter optimization balancing complex constraints such as speed versus power or frequency versus slew rate versus offset for analog circuits Star Hspice Manual Release 1998 2 3 3 hspice book hspice ch03 4 Thu Jul 23 19 10 43 1998 Understanding the Data Flow Specifying Simulation Input and Controls Understanding the Data Flow Star Hspice accepts input and simulation control information from a number of different sources It can output results in a number of convenient forms for review and analysis The overall Star Hspice data flow is shown in Figure 3 2 To begin the design entry and simulation process create an input netlist file Most schematic editors and netlisters support the SPICE or Star Hspice hierarchical format The analyses specified in the input file are executed during the Star Hspice run Star Hspice stores the simulation results requested in either an output listing file or if OPTIONS POST is specified a graph data file If POST is specified the complete circuit solution in either steady state time or frequency domain is stored The results for any nodal voltage or branch current can then be viewed or plotted using a high resolution graphic output terminal or laser printer Star Hspice has a complete set of print and plot variables for viewing analysis results The Star Hspice program has a textual command line interface For example the program is executed by entering the hspice command the input file name and the desired options at the prompt in a UNIX shell on a DOS command line or by clicking on an icon in a Windows environment You can have the Star Hspice program simulation output appear in either an output listing file or in a graph data file Star Hspice creates standard output files to describe initial conditions ic extension and output status st0 extension In addition Star Hspice creates various output files in response to user defined input options for example a design tr0 file in response to a TRAN transient analysis statement The AvanWaves output display and analysis program has a graphical user interface Execute AvanWaves operations using the mouse to select commands and options in various AvanWaves windows Refer to the AvanWaves User Guide for instructions on using AvanWaves 3 4 Star Hspice Manual Release 1998 2 hspice book hspice ch03 5 Thu Jul 23 19 10 43 1998 Specifying Simulation Input and Controls Understanding the Data Flow Command line input AvanWaves graph and analysis meta cfg output configuration file design tr graph data output file hspice ini initialization file design sp netlist input file Star Hspice simulation Models and device libraries command inc command include file optional Printer or plotter Other output files design lis design mt design sw design ms design ac design ma design gr design pa design st design ft design a2d Graphics hardcopy file Figure 3 2 Overview of Star Hspice Data Flow Star Hspice Manual Release 1998 2 3 5 hspice book hspice ch03 6 Thu Jul 23 19 10 43 1998 Understanding the Data Flow Specifying Simulation Input and Controls Simulation Process Overview Figure 3 3 is a diagram of the Star Hspice simulation process The following section summarizes the steps in a typical simulation 1 Invocation hspice i demo ip o demo lis 2 Run script Select version Select best architecture Run Star Hspice program 3 Licensing 4 Simulation configuration Find license file in LM LICENSE FILE Get FLEXlm license token Read meta cfg or Read installdir meta cfg 5 Design input Read input file demo sp Open temp files in tmpdir Open output file Read hspice ini file 6 Library input Read INCLUDE statement files Read LIB Read implicit include inc files 7 Operating point Initialization 8 Multipoint analysis 9 Single point analysis 10 Worst case ALTER 11 Clean up Read ic file optional Find operating point Write ic file optional Open measure data files mt0 Initialize outer loop sweep Set analysis temperature Open graph data file tr0 Perform analysis sweep Process library delete add Process parameter and topology changes Close all files Release all tokens Figure 3 3 Star Hspice Simulation Process 3 6 Star Hspice