Pegasus: Get your Wings: Pegasus Results Viewer- LVS

In our previous blog we introduced Pegasus Results Viewer (Pegasus RV) and gave detailed introduction to Pegasus Results Viewer for DRC. In this blog we will talk about Pegasus RV for LVS.

Pegasus RV for LVS provides a smooth navigation through LVS and ERC results. Cross-probing in Pegasus RV is one of the useful function that allows highlighting devices and nets in the design and finds their corresponding ones on other side (schematic or layout). Stamping Conflicts Debugger provides capabilities to visualize stamping conflicts and Interactive Short Locator provides powerful capabilities to debug shorts.

Let us discuss this in detail starting with PEGASUS RV for LVS interface.

Pegasus Results Viewer for LVS Interface

Pegasus RV-LVS interface is a user-friendly tab-based interface. All LVS and ERC results are listed in one place: Extraction results, ERC results, Pathchk errors, Stamping conflicts errors, Shorts, and Comparison results. It has tree-based representation of errors. 

When a run completes, the summary of the results is displayed giving you an option to select/deselect the results you want to see or not.

Let us explore the components of the interface a little more.

Files Browser lists the Input, Output and Statistics files.

Double-click any file to view its contents in a separate tab.

As mentioned in the beginning that Pegasus RV-LVS is a tab-based interface and shows each type of results in a separate tab for the ease of debugging and helps you focus on a specific area. For example, the Extraction tab lists device extraction and connectivity extraction results. You can select any violation group to view report content. Click on a link, as shown in the image below, to highlight reported violation.

The Comparison tab shows the comparison results. Just like the Extraction tab you can click on any cell or violation group to view report content and clicking on the link highlights the reported net or device.

The ERC tab shows ERC rules results. You can double click on the ERC RESULTS file to open results in a separate tab.

The ISL tab lists shorts being found in the design. The Interactive Short Locator identifies shorts by a net containing two or more labels that are not the same. The interactive short locator identifies and displays the paths between the shorted labels. The path consists of shapes from the connected layers specified in the rule file. You can use the interactive short locator to find the shape, or shapes, which are causing the short. It’s a three-step process:

1. Selecting net to debug.

2. Setting Options.

3. Viewing and analyzing results.

The Results panel displays the results of the analysis engine and provides navigation through the errors, marking shapes as part of the selected net, and re-running or stopping of the analysis engine.

To explore ISL in detail, you can go through Pegasus Interactive Short Locator RAK and Pegasus Interactive Short Locator V20.2 (Channel Video) video.

The SCD tab lists stamping conflicts being found in the design. The SCD form is divided into two steps-- Step 1: Select conflict to debug and Step 2: Results.

You can debug the stamping conflicts by analyzing results listed in the Results panel of Stamping Conflict Debugger tool. You can also highlight the results in the design to view the conflict and fix it there.

You can highlight the results either by selecting path, group, nets, and output from the Navigation Tree section or by clicking selected or rejected nets in the Report section. After you have located the issue in the design, you can fix the same in the design.

For more details, you can refer to Stamping Conflict Debugging In Results Viewer: Introduction And Lab Guide.

Probing

Pegasus RV cross-probing functionality allows debugging LVS errors by probing nets and devices using the LVS probing tool. By highlighting nets and devices with the probing tool, you can locate the corresponding problems in a layout or schematic or netlist window.

You can probe errors through the Pegasus Probing form, or the Textual Viewer, or the Report section. Pegasus RV supports cross-probing between: DFII-DFII, DFII-Netlist, Netlist-Netlist, GDS-Netlist. Supported layout viewers are Virtuoso, Design Review, and Innovus.

What I have included in this blog will give you pointers to explore Pegasus RV for LVS. You can also go through Pegasus Results Viewer 002 - LVS RV Overview (Video) and read Pegasus Results Viewer chapter in the Cadence Pegasus Users Guide.

Special thanks to Oleg Dobrovolskiy who is the subject matter expert of this blog.

About Pegasus: Get Your Wings

"Pegasus: Get your Wings" is a blog series to showcase the capabilities of Pegasus and to familiarize you with its notable features.