DAI Signalscan User's Guide

CHAPTER 1 Introducing DAI Signalscan

Overview 1-3

Features 1-3

Overview of DAI Signalscan Components 1-5

Multivalue Indication 1-6

Sequence Time 1-7

Do-Files 1-7

Signalscan TX 1-7

Signalscan Turbo Compression 1-7

Signalscan Multisim 1-8

Overview

DAI Signalscan is a powerful tool for interactively debugging simulations and analyzing simulation results. It plays a very important role in the verification cycle, allowing you to analyze large amounts of complex simulation data quickly and accurately.

The key to Signalscan's high performance is the DAI SST2 (Signalscan Turbo 2) Database. SST2 Databases from different simulations may be opened and viewed simultaneously. The SST2 Database may be written directly from the Verilog or VHDL simulator via the Signalscan PLI routines or generated by automatic translation of VCD files. For design flows that rely on VCD files, Signalscan can translate SST2 Database to the VCD format.

Each of Signalscan's major windows is described in "DAI Signalscan Windows Overview". These windows give you different views of the design and control over the simulator's execution. The windows are interactive and linked together in time.

Signalscan can connect directly to your simulator, allowing you to control the simulation through Signalscan and graphically view simulation results as they are generated. Simulation results can also be saved to a file and analyzed at a later time. Results from several previous simulations may be viewed together in the same window with data from a currently running simulation, allowing quick and easy comparison with past results.

Features

Signalscan has the following main features:

Table 1-1. Signalscan Features
Feature	Description
Fast	Reads data from a 500+ Mb simulation file in seconds.
Easy	Intuitive graphical user interface.
Multiple simulator support	Avanti HSPICE, Polaris Cadence Leapfrog, NC Verilog, Verilog-XL ModelTech ModelSim EE, Verilog, VHDL Synopsys EPIC Tools, TimeMill, PowerMill, VCS Fintronic FinSim Frontline PureSpeed SpeedSim SpeedSim/3 Simucad Silos III Compass QSim Meta-Software HSPICE
Analog/digital wave support	Displays analog and digital waveforms in the same window.
Source code debugging	Integrated environment for source code debugging.
Register window	Allows creation of multiple customized views of variables and text.
Sequence time	Records actual order of simulation execution. Allows analysis of simulation results from different simulators.
Multivalue indication	Identifies times where signals have more than one transition in the same "zero time" timestep.
Backtracing	Graphical schematic tracer creates "on the fly" schematics. Allows determination of the cause of contention and undefined signals. Allows design queries: What path propagated this signal?
Data recording	Fully user programmable: what you want to record. "Snapshot": programmatically records portions of simulation without stopping the simulator.
Multiple files	Displays multiple simulation data files simultaneously.
SST2 Database	Robust, high-performance, and compact database. Automatically created from Verilog or VHDL run via PLI. Information stored: strength, hierarchy, fan-in, buses, events, and signals.
Simulation control	Menu-driven simulation control within the Signalscan environment.
Help	Online hypertext help.
Analysis modes	Supports both Interactive and Batch modes of debugging.
Scripting language	Has a powerful scripting language to automate repetitive tasks.
Cause Finder	Allows you to go from a variable or structural element to the cause of the selected value of that element displayed in either the Source Code Window or the Schematic Tracer. You can also go to the definition of a variable or a module instantiation in the Source Code Window.
Transaction-Based Verification	Allows you to work with your model at the transaction level, a functional level above the signal level.

Overview of DAI Signalscan Components

SST2 Database

Simulation results are kept in a database known as the DAI SST2 (Signalscan Turbo 2) Database. The SST2 Database stores simulation results and other design information in an efficient format that allows data to be loaded very quickly. SST2 PLI routines, included with Signalscan, may be linked into your Verilog or VHDL simulator, giving it the ability to write to the SST2 Database directly. Signalscan can also convert Value Change Dump (VCD) files and files written by various analog simulators to the SST2 Database.

Access to the SST2 Database is very fast. This allows all or most of the design to be recorded in the SST2 Database, even with very large designs, so that the simulation can be run just once, without having to know in advance what parts of the design will be viewed.

Design Browser

The Design Browser efficiently supports large designs. With it, you can easily navigate the design hierarchy, view scopes, and select variables for analysis. Filter options let you focus on the data of interest.

Waveform Window

The Waveform Window lets you view the results of multiple simulations from Verilog, VHDL, and analog simulators, all in the same window. The Waveform Window displays signal strengths, Multivalue Indication, and Sequence Time, a DAI innovation.

Register Window

The Register Window lets you create multiple customized views of your design. You can lay out user-configured register pages of variables and buses intermixed with text.

You can define, view, save, and restore any number of different Register Pages. Since you can display multiple pages, comparisons are an easy task.

Schematic Tracer

After selecting a signal from any Signalscan view, the Schematic Tracer may be used to display a graphical view of its sources. Values are provided for every displayed signal. By simply double-clicking on a source, you can graphically backtrace through your design very quickly.

Multivalue Indication

Multivalue Indication graphically identifies areas where sequence order problems may exist: zero-time glitches where variables have received multiple values during a single time step. Such a glitch may indicate a reliance on the simulator's ordering of events, which could later turn into a serious timing problem. Once a glitch is identified, the problem may be investigated further by expanding into the Sequence Time domain.

Sequence Time

Sequence Time (patent pending) lets you view and debug activities which conceptually take place at the same instant, but which the simulator executes in a specific order. When different execution orders yield different results, a sequence order problem exists. By graphically displaying the actual variable assignment sequence within a given time step, Sequence Time lets you pinpoint and eliminate these classes of problems early in the design cycle before they result in more serious gate-level problems downstream.

Do-Files

The set of variables being viewed and other configuration information and preferences may be saved in a file known as a Do-File. A Do-File is a text file containing Signalscan commands, which may be re-executed at a later time. Using a Do-File, you can restore a previous configuration, view a particular set of variables, or perform any sequence of Signalscan commands quickly and easily.

Signalscan TX

Signalscan TX adds interactive source code debugging and transaction-based verification to the capabilities of Signalscan.

The intelligent source code parser displays variables, keywords, and comments in different colors for easier source code viewing. Step through the source with the press of a button. By simply clicking on the source code, you can set breakpoints and add variables to the Waveform Window.

Transaction verification allows you to work with your model at the transaction level, a functional level above the signal level. You can associate properties, such as address and data values, with your transactions to help you understand your system. You can define error transactions and then easily locate each error occurrence. When you need to, you can still work at the signal level.

Signalscan Turbo Compression

The optionally licensed Turbo Compression feature provides an additional level of data compression/decompression when writing and reading the SST2 Database. Users who are verifying large designs or lengthy regression vector sets will enjoy higher capacity.

Signalscan Multisim

The optional MultiSim feature adds the ability to open databases created for selected simulators via translation. Check DAI's website (http://www.designacc.com/ ) for a list of simulator files that require this feature.