ToolsSynopsysTutorialsBasicVCS

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Contents

Architectural choices, RTL compilation and simulation with DVE

Objective

Learn the commands and how to compile the design with DVE

Introduction

The Synopsys simulator is called VCS, but it is used through an interface called Discovery Visual Environment (DVE) which is an interactive Graphical User Interface (GUI) used for debugging SystemVerilog, VHDL, Verilog, and SystemC designs. Using DVE you can drag-and-drop signals in various views or use the menu options to view the signal source, trace drivers, compare waveforms, and view schematics. Use DVE to quickly find bugs in RTL or gate, assertions, testbench and coverage.

Laboratory tasks

For this tutorial you need to download the dve.zip file (attached at the end of the wiki page) and unzip it in the syn_tut directory.

Start DVE graphical user interface (GUI) from the work directory.

Bring up DVE and open Johnson_count.v using the following commands:

% cd synopsys

% . syn_setup

% cd syn_tut

% cd dve

% cd work

% vcs ../source/Johnson_count.v –R –gui –debug_all

Image002.jpg
Fig.1 DVE Top-level GUI window

From menu bar select Simulator > Setup, then select Start the simulation from the Simulator Setup dialog box (Fig.2)

Image004.jpg
Fig.2 Simulation setup

3. The Simulation setup has the following options:

Simulator Executable - specifies the name of a simulator executable.

Simulator arguments - identifies the simulator arguments.

Interactive VPD file - specifies the name of the VPD file. VPD files (design database files) are platform-independent, versioned files into which you can dump the selected signals during simulation. DVE gets hierarchy, value change, and some assertion information from these files.

Current directory - specifies the full path of the simulator executable.

Image006.jpg
Fig.3 Overview of DVE window

A. TopLevel window contains

1. frame,

2. menus,

3. toolbars,

4. status bar,

5.pane targets.

Viewing a Waveform

Hierarchy Pane - displays the scope hierarchy of the design.

Data Pane - displays the variables of the selected scopes of the Hierarchy pane.

Source View - Displays the source code and supports source code relative features, such as tracing driver or load, and setting line breakpoints.

List View - provides a table view to display the values of signals over time.

Schematic View - provides a module-based schematic to display the connectivity of the object.

Assertions View - displays the summary of assertion results of simulation including the success, failures, and the incomplete ones.

To view waveform information for signals in the Wave view (Fig.4).

1.Image008.jpg

Select a scope or object from the Hierarchy pane, Data pane, Source view, List view, Schematic view, or Assertion view.

2. Click the Add to Waves icon in the toolbar.

Using Simulator Menu Commands Runs the simulation until a breakpoint is hit, the simulation finishes, or for the duration specified in the set Continue Time dialog box or toolbar time entries.

Image011.gif

When the simulation is running, this icon is activated. Click to stop the simulation.

Image013.jpg
Fig.4 Wave view window

Tracing Drivers and Loads

1. Trace drivers and loads of a signal at any time to see the drivers/loads that caused a value change and see all the drivers/loads that possibly contributed to a signal value.

2.Select a signal in a view or pane. For example, Data pane, Source view, List view, etc.

3. Right-click and select Trace Drivers or Trace Loads. When a driver is traced, a new Driver pane will be created if none exists in the current top level frame. If a driver pane exists, the driver information will be added to the top of the list.

Additionally, the first driver will be highlighted in the Source view and annotated with a blue node in the gutter. In the Wave view, double-click on a waveform to see its drivers (Fig. 5).

Link the Driver panes to Source view in the same top level frame and Path Schematic view. The Link to radio buttons, at the right top of the pane, shows the current linked windows. By linking a Source and Schematic view, when the object is selected in the Drivers pane, the object will also be selected in the linked views.

Image015.jpg
Fig.5 TopLevel window with tracing drivers and loads

Comparing Signals, Scopes, and Groups

For comparing individual signals with the same bit numbers, scopes (for comparing variable children), buses, or groups of signals from one or two designs.

To view a comparison

1. Select one or two signals, signal groups, scopes, or buses from the Signal pane of the Wave view.

2. Right-click and select Compare.

Image017.jpg
Fig.6 The Waveform Compare dialog box

3. Click Load Reference Signals/Scopes and select the text file with the signals and scopes to reference.

Note: If comparing two designs from root, then the reference waveform region and test waveform region can be empty.

4. Click the More Options button (Fig. 6).

The dialog box is expanded and additional options are displayed.

5. In the Signal types and ignore options section, select the signal types to compare and select ignore options. For example, if Ignore X is selected and if the reference signal value is X, there is always a match, whatever the values of the Test Signal.

6. Enter a Time Tolerance to filter out mismatch values that have time ranges smaller than the tolerance range.

7. In the General section, select to compare recursively or to only create signals with mismatches.

8. Enter mismatch settings for maximum mismatches per signal and maximum total mismatches to report.

9. Click Apply to start the comparison and keep the dialog box open. Or click OK to start the comparison and close the dialog box (to open it at any time from the Signal pane CSM). Results are displayed in the current Wave view.

10. Select a result in the Wave view, right-click and select Show Compare Info.

Image019.jpg
Fig.7 Compared Signal Groups in the Wave View

Selecting signal in the Schematic View

To select a signal in the Schematic view

1. Enter the signal name in the Find toolbar box in the Schematic view, and then click the Find Next toolbar button. The signal is highlighted in the schematic.

2. With the signal selected, click the Trace Drivers toolbar button, or select the Trace-Drivers menu item. The signal is highlighted in purple (Fig. 8).

Image021.jpg
Fig.8 Highlighted Signal Groups in the Wave View

Using User-defined Radixes

This section describes how to create, edit, import, and export user-defined radices. You can define a custom mnemonic mapping from values to strings for display in the Wave view.

To create, delete, import, and export a user-defined radix

1. Select Signal Set Radix User Defined Edit.

2. Click New, enter a radix name, and then hit the Enter key on your keyboard. All buttons on the Edit User-defined Radix get enabled.

3. Click Add Row to activate a row for the user-defined radix and perform the following steps:

- Select the text and background colors for each row entry.

- Select the radix, click a cell in the Value and Display column, then enter the values. The radix is edited.

4. Select a row, and then click Delete Row. The row is deleted.

5. Select a radix from the Radix Table Name drop-down and click the Delete button. The radix is deleted.

6. Click Import, then browse and select the desired radix. The radix is imported.

7. Click Export, select the radix, and then enter a radix name. The radix is exported.

8. Select the Apply user-defined radix to selected signal(s) checkbox (Fig. 9). The user-defined radix is applied to the selected signal in the Wave view.

9. Click OK or Apply to save the user-defined radix.

Image023.jpg
Fig.9 The Edit User-defined Radix dialog box with Wave view window

To exit DVE write exit in the command line on the console.

DVE> exit

Other resources

Directory for tutorials for Synopsys tools

Wiki page for Tools

Files used in this tutorial

  • dve.zip: Zipped archive of dve directory
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