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Board Revolution

Part 2 - Mentor Xpedition

Mentor Graphics is number one in PCB design tools. They want me to tell you that. They want me to tell you that – even after reading about my disdain for marketing the market share of your product. So – there ya go. They’re number one. Why does this matter? Well, they rightfully point out that nobody ever got fired for buying the leading tool, and that EDA can be a fickle business. If an EDA tool is number one (they observe), the company selling it probably cares about it deeply and will want to go the distance to support you and make you happy. Point taken.

However, since we’re all engineers here, the thing that matters the most – by FAR – is whether the tool is robust and reliable in helping you get your engineering job done. In this case – that means helping you be as productive as possible designing the heck out of your PCB. Luckily, besides being number one, Mentor has done a very respectable job of that as well. Now, however, they think that’s not enough. They’re launching a big ’ol ambitious program to upgrade their PCB design suite – in a clear effort to fend off the similarly ambitious competitors (Cadence, Zuken, Altium, et al) who are coming full-tilt right at them.

PCB design ain’t what it used to be. Today, designers have to contend with extreme performance constraints, high-speed interfaces, signal integrity, ultra-tight pin grid spacings on massive devices, and complex systems that transcend the board and connect to just about every other device on the planet. Our design teams are scattered all over the planet too, so we have to coordinate and manage complex design projects across diverse, multi-disciplinary teams that are often not co-located – in time or in space. Sounds tricky, huh?

Mentor is signaling the overhaul of their PCB tools with a subtle name change. That’s the trick – just enough to get your attention, but not so much that you don’t recognize the, y’know, number-one-ness of it. They’ve dropped the E. Now, it’s just “Xpedition.” Cool? It has the Xtreme vibe and it Xplains that they’re adding some Xtra features that are Xcellent. This announcement is billed as the first wave of a major upgrade of Mentor’s “Enterprise-level” PCB system design suite. Mentor also markets a lower cost “desktop” solution called PADS.

OK, enough marketing merriment – what are these new features and what do they buy us? In a similar vein to the Cadence Allegro upgrades we discussed in part 1 of this series, Mentor has put a lot of energy into making routing more efficient and productive. Mentor’s upgrades start with placement, however. Placeable components can be grouped hierarchically, and those groups can be assigned a rough placement. This gives you a high-level floorplan for your board: “OK, the analog lines come in over here from the connector, the processor and memory interface go up here, the FPGA and all the initial signal processing stuff go over here….” Then, starting with that high-level plan, you can do detailed placement of the individual parts of each hierarchical group. Intuitively, it really helps manage the complexity of the placement process and gives your board a level of logical organization that is difficult to achieve with a giant netlist of random parts.

Visualizations help you see how the groups and parts you’re placing are interconnected, and static groups (such as connectors, for example) can be fixed at specific locations. You can also create detailed designs (including routing) for component groups and re-use them – locking and protecting your hard-earned optimizations. 

Moving on to routing: Mentor has introduced a very intuitive route sketching capability. Basically, you can select large groups of connections and then hand-sketch with broad gestures – telling the system how you’d like those traces routed. Xpedition will follow your guidance, doing the detailed routing and automatically honoring the design rules. You can specify your own routing style, via patterns, pad entries and so forth. I’ve watched this process, and the results look almost indistinguishable from hand routing. Because of the type of manual guidance you are able to provide and the way the system reacts to that guidance, the tell-tale artifacts that are normally associated with automatic routing are all but gone. If a tiny bit of cleanup is needed, the usual pushing and shoving will easily get you what you want.

For performance-critical interfaces such as differential pairs, phase and length matching are done automatically. The system can also generate curved traces where needed, and it can do symmetrical pad entries – the same way you’d do them manually. The overall impression of the upgraded routing system is really nice. It feels like it would be very easy to route a complex, heavily-constrained design and get results that feel like meticulous hand routing in a tiny fraction of the time required to actually do meticulous hand routing.

Next, we slip on the 3D glasses and dive into the video-game world of full physical visualization. Xpedition has added a Z-axis, and your design can now be viewed and edited seamlessly in either 2D or 3D views, all operating off the same model and database. Since both views operate on the same model, selection and editing work smoothly as you switch views back and forth. You have a full complement of 3D visualization and manipulation features, and the performance is outstanding. While 3D board design was a bit of a novelty a few years ago, today’s space-constrained enclosures, rigid-flex boards, and more sophisticated connectors really benefit from the huge amount of additional information available in a 3D view. Used properly, it should smooth the interface with your mechanical people and drastically reduce iterations between the electrical and mechanical domains while working toward design closure. 

Of course, 3D design works only if you have models. Mentor says they have a library with more than four million vendor parts. Apparently, they’ve had elves cranking out 3D models for decades. They also provide tools for importing models, or for creating your own – you know, if you just happen to really, really need that four-million-and-first one.

There will be those who see some of the enhancements to the user interface as “dumbing down” the board design tools. Certainly, if you feel your value-add is a detailed understanding of thousands of obscure board design commands and hot-key sequences, you won’t like any kind of change in your design environment. Today, however, more and more engineers are spanning larger parts of the system design process, and fewer people have the luxury of spending a large portion of their careers just learning the subtleties of a single piece of software. Engineers want to get into the board layout tool, get the job done well, and move on to other important engineering tasks.

Since we’ve looked at two competing systems in as many weeks, people will want to know “who wins?” The answer, of course, is “all of us.” With big EDA companies investing heavily to outdo each other in the board design space, we’re guaranteed to get better tools – no matter which ones we choose. So, congratulations, you win!

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