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DESIGNCON FUSION

by Tom Cantrell

Start ę ASSICs? ę Tail Wags Dog ę Shades of Gray ę You Only Live Twice ę Nice ICE ę Sources and PDF

NICE ICE

Back in the old days, blood, sweat, and tears were the way systems got debugged. I brought up a lot of designs relying on little more than a logic probe and a lot of head scratching.

Not to mention I had to walk 20 miles barefoot through the snow to get to kindergarten. You know how the story goes.

The fact is, times have changed. The old logic probes and oscilloscopes are pretty useless when it comes to poking around the innards of a zillion gate chip.

Generally, simulation has been the only recourse. But simulation isnęt without its problems, foremost being the fact that itęs only a simulation.

The idea of running something at a fraction of real time on a screen only goes so far. Itęs OK for finding the most obvious "oops" bugs, but does little to counter the corner cases encountered in the real world. Itęs also inadequate for pipelining the overall system design (i.e., software types still twiddle their thumbs while the chip designers muddle through simulation clock-by-clock).

More importantly, it overlooks the fact that the true virtue of real hardware isnęt just to verify that the chip does what you want, but that what you want is really what you want. Anyone whoęs developed a product knows that the first prototype is a testbed that ultimately leads to new and improved features in the final version.

Thatęs why using FPGAs to emulate an ASIC is such a popular concept, and why the Aptix System Explorer is so nifty (see Photo 4).

Photo 4ęChuck your scopes and probes. This season, the well-heeled designer sports an Aptix System Explorer, the mother of all emulators. (Click to enlarge)

Combining a bunch of Xilinx parts with its own programmable routing chips, in essence the System Explorer is a huge 47-lb. FPGA that can prototype chips with millions of gates and megabits of RAM. It "only" runs at up to 40 MHz, but thatęs still faster than a simulator and "real-enough" time for many applications.

Starting at $150k, the System Explorer certainly isnęt an impulse buy, but nobody said things would be easy (or cheap) in the SoC era. Better get ready for a new ICE age, lest you end up like our reptilian friends who didnęt make it through the last one.

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