Things You Didn't Know About Virtuoso: Navigator Assistant

26 May 2009 • 3 minute read

Have you ever found yourself working with a massive schematic having to constantly zoom and pan around to find the block you're looking for (since they all look alike from high altitude)? Then you descend into the block only to find that the sub-block you really wanted is somewhere else? Well, pop back up and start over again...

Have you ever run a simulation which finds a problem with transistor I44.I23.I0.I25.NM2? Again, you zoom and pan around looking for instance I44, then descend into it and do some more zooming and panning to find I23. Lather, rinse, repeat until you finally arrive at our destination. Maybe you have a dim recollection that there is a search function somewhere in one of the menus, but can't remember which one.

We've all been there. Now there's a better way. The Navigator Assistant in IC61 was designed to overcome the frustrations of situations like these (and many others). Just select Window->Assistants->Navigator (or click the right mouse button (RMB) near the top of the design window and select Navigator). The Navigator Assistant will appear docked at the side of the schematic canvas. It displays the design hierarchy in a tree representation.

"That's nice", you say, but what does that get me?

Remember that sub-block you were looking for, but couldn't remember where it lived in the hierarchy? Now all you have to do is click on the little plus signs ("+") next to any of the listed design blocks to expand the tree underneath. Do this across as many levels as you need to find what you're looking for. What can you do now that you've found it? Click RMB->Open Instance... to open that cellview without having to open any of the intermediate levels.

Remember I44.I23.I0.I25.NM2? Well, look at that...now you can easily see which one is I44, even from 30,000 feet up. Just as easily you can find I23, then I0, then I25. RMB to open I25. Right there in the Navigator, you can see NM2. Click on it to select it (you did notice that selecting something in the Navigator cross-selects it in the schematic canvas, didn't you?). There you go...5 clicks, no zooming, no panning, no pushing or popping.

Extra Navigator Tips

You can use Shift-click and Ctrl-click to select multiple items in the Navigator, just as in most PC applications.

If you are zoomed in on an area of the schematic and you select an instance in the Navigator which isn't currently being displayed, the schematic will automatically pan over to show what you just selected.

You can add additional columns to the Navigator display such as Library Name and Lock Status (who is currently editing each cell and on which machine) by clicking RMB on the gray column header.

Notice the "Name" field at the top of the Navigator. It's actually a special field that you can customize. RMB anywhere below the gray column header and select Options... The top section of the Options form allows you to customize what gets displayed in the Name column of the Navigator to make it easier to read.

At the bottom of that Options form, you can set the default behavior when you execute the shortcut "Open Instance" command from the RMB context menu (edit/read, current tab/new tab). For example, I always like to open sub-blocks in a new tab so I can easily switch between them.

Finally, the Navigator traverses the design hierarchy based on a default view name list. If you routinely use view names other than "schematic", for example, you may need to change the view name list to get the Navigator to display properly. The view name list can be found under Options->Editor... in the schematic banner menu. Of course, view name switching can also be controlled from the Hierarchy Editor and the Navigator display will be updated automatically.

What Else?

Lots more information on the Navigator can be found in the Virtuoso Schematic Editor XL User Guide. There's also a nice video demonstration of the Navigator in the Virtuoso Custom IC Video Library on Sourcelink.

What's Next?

Stay tuned to this space to see how to teach an old dog a new trick.

Stacy Whiteman