IC Packagers: Navigating Your Visible Design

Last week we introduced you to the new dark theme. But we listen to your suggestions for ideas of other ways to improve your ability to move around your design efficiently. That brings me to two other items that you have your peers in our loyal community to thank for.

Both of these target your ability to see what you need to (and not what you don’t) by filtering the active elements in the canvas as you are working. Design sizes are increasing. Pin counts are rising. Degassing holes are getting smaller. All this is leading to a complex flood of information assailing your eyes wherever in the drawing you look.

How can you reduce that strain? And can you do it without constantly moving your mouse off the canvas, away from what you’re working on? You sure can!

Layer Select Mode and Moving Up/Down Your Cross-Section

The layer select mode is not new to the latest hotfixes (ISRs) of 17.4. It has been around for some time. When active, it turns the layer names in the Visibility pane into hyperlinks. With a click, you can switch off the current layer(s) and turn on the new layer you want to look at.

You can, however, do much more than that in layer select mode. Did you know that, if you want to see the first three layers of your design – maybe you’re routing on layer 2 – you can select the first layer and, while holding the Shift key, select the third to enable all the layers between those two, like in many other spreadsheets of information? Well, you can! Control-click works to toggle a single layer, as well.

What IS new with dark theme, though, is that your bond wire profiles and custom visibility layers can also be selected this same way. If you need to see the top conductor layer but also PROFILE1 and PROFILE2, use the Control key to toggle these on as well. Turn on the constraint regions so you can see as you get close to a boundary.

This can save you the trouble of setting up many different color views and films to store in the view pulldown. The views take two clicks to activate; one opens the list, the next picks the view.

The trouble with any of the above is that you can’t easily make changes without abandoning your focus on the canvas itself. Every time you do this, your concentration is broken, and you slow down. Which brings me to the tidbit of goodness you might not otherwise see.

Whenever layer select mode is active, the page up and page down keys will cycle up and down the cross-section layers. Page down when you’re on top to move down to M2. Again, you will move to M3; page up to move back up a layer.

Most of us can find these keys on the keyboard without our eyes leaving the screen at all. And the savings, over time, really adds up!

Filtering Small Objects from the Display

If you have 100,000 pins in your die or 250,000 vias on a layer, odds are good you don’t want to see them all constantly. The Allegro product line added a size-based filter, which suspends drawing of items smaller than a given number of pixels, in the 17.2 release stream. When on, if you set the minimum value to 5 pixels, any of the eligible object types that aren’t at least that big are suppressed from the display.

As you zoom in, these objects get bigger, and they then draw on the screen. In this way, you can see the large objects like components and design outlines, when zoomed out; zoom in, and you see the detailed routing. You don’t need to leave the canvas to adjust things. Simply zoom the display.

Feedback we’ve received, however, is that bringing up the color dialog to change the setting for the filter size is clunky. If the goal is to keep your focus on the design, this need breaks from that objective.

With 17.4 and dark theme’s release, that is why a command, display filter size, has been added. This command without any arguments does nothing. If you pass in a number 0-100, the object filter size is reconfigured to that immediately and the screen refreshed.

The REAL power (in my opinion) comes when you pass an argument of “up” or “down”. This will increase/decrease the filter size by one-pixel step each time. In the movie above, I’ve aliased these two commands to keystrokes I can use interactively on my design.

• alias + design filter size up

• alias - design filter size down

With these, I can press the + key to increase the size of my filter. Now, whenever I am looking at the screen and find myself bombarded with too much detail, a few presses of the + key will clear out the smallest items and allow me to focus.

Cadence doesn’t default these aliases for you, but you can set them for yourself. You might have bindings to these keys already, and we don’t want to break those. But, if you watched the video above and how I can, at the push of a button, hide the BGA balls while still seeing my routing traces and component outlines, I think you’ll agree that this is a vastly more friendly model for filtering unwanted design elements by size.

How Do You Remain Focused?

These are a few ideas that our users have shared with us to allow them to better work with their designs. Are there things you do – whether they be aliases, function keys, scripts, or even SKILL code – that help you? Do you think others may benefit from your knowledge? Share with us! Maybe next release, your tricks will be an integral part of the use model for everyone!