Monday, November 12, 2007

System-Level Design Includes the PCB

Portable Design just received an overdue data dump from Mentor Graphics on PCB design. This a design area that we have largely overlooked in the magazine, which is particularly inexcusable since I used to be Asian editor for Printed Circuit Design Asia back when it was a Miller Freeman book. If you remember Miller Freeman, you probably also remember through-hole circuit boards. We’ve just established that you’ve been around for a while.

Anyway, John Isaac, director of systems market development in Mentor’s Systems Design Division—‘systems’ being something that they rightly define as extending to the edge of the PCB, not just the SoC—talked me through the complexity of placing and routing highly complex designs in FR4 instead of CMOS. Automated tools can do the job quickly but not very elegantly; hand-tooled approaches can save a lot of architecture, but at the expense of a lot of time. Mentor’s XtremePCB lets designers start with manual placement; do a quick auto-route; and then try to hand optimize the results.

The preferred alternative is to turn next to XtremeAR, which Isaac claims is “the first time that auto-routing has been applied to multiprocessing on a PCB.” In addition to doing auto-routing, you use Topology Planning to let the routing tool try to further optimize sections of a design—say the data and control paths between a CPU and a graphics controller. The results, in the demo, look far cleaner and more compact than the results from traditional auto-routing. I/O Designer allows parallel place and route of FPGA and PCB designs, enabling a much more compact PCB design, since you can lay out the components in the FPGA to maximize board efficiency.

Most interesting was taking a holistic approach to board design. XtremePCB manages a central database that enables globally-dispersed designers to work on the same board design in real time, working on a central database to which everyone has different access privileges, even component suppliers. Purchasing could reject a component as being too expensive—or the supplier could flag it as not being available in time or in sufficient quantities—and substitute another; this new part can then be evaluated and incorporated into the design before the board is even prototyped.

Suffice it to say that (1) PCB design has come a LONG way since I covered it closely ten years ago and (2) Portable Design will be covering it a lot more closely going forward.

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