Viewpoint

The System IC Virtual Prototype: Virtually Certain to Be an Industry Milestone System-on-a-chip ICs are more than just hardware; they're software too. Hardware/software integration is key to the realization of a final product. by Tom Dille

The ongoing advances in process technology, combined with market-driven requirements for the lowest possible cost per function, are making the complex, processor-based system on a chip (SOC), or system IC, the solution of choice for a growing number of applications. At the same time, the pressure to get these complex ICs to market quickly and reliably is, if anything, increasing. Consumer, telecommunications, and other markets for ICs exert intense time-to-market pressure that is in direct conflict with both the increasing complexity of the ICs themselves and the increasing amount and complexity of the application-specific software required to address those markets.

Arising out of this need to get ever more complex SOCs to market ever more quickly are some revolutionary new design techniques and tools that are changing the face of the industry. Key among the techniques are design reuse and hardware/software coverification.

The advent of the intellectual property, or IP, industry is providing a basis for SOC design. At the same time, both the complexity and the core-based nature of SOC design are shifting the focus of the design process from logic design to hardware/software codesign and coverification. The ideal development environment is becoming one that is used to integrate existing cores, support software as well as hardware development, optimize cost/performance on an architectural level, generate the logic required apart from the cores, and most of all, verify functionality and performance presilicon. This is the virtual prototyping environment.

The term "virtual prototype" has been applied to so many situations that it has little meaning by itself. I define a system IC virtual prototype as a bit-, pin-, and clock-accurate (RTL-accurate) software simulation model of a system IC's hardware together with its associated application software. Such a model is necessary because application software is developed on that hardware model and because the hardware model is then used as the basis to create actual hardware through the use of logic synthesis and other EDA tools.

When made available early enough in the design cycle, this executable model makes possible the kind of concurrent hardware/software engineering and system-level design verification that are needed to get complex systems on a chip to market quickly and reliably. Indeed, for the most complex multiprocessor devices, the virtual prototype may provide the only environment in which the hardware can be debugged.

The full potential of designing with virtual prototypes has only recently been made possible with the development of sophisticated behavioral modeling tools and other tools for working with the virtual prototypes themselves, both in the software and the hardware domain. Three major factors had to be addressed to make virtual prototyping an effective technology. I've already described two: bit-, pin-, and clock- accurate simulation models and early availability. The third is speed: The virtual prototype's hardware model must simulate fast in order to provide a viable environment for software development and subsequent system-level design verification. In fact, a C model is typically required.

The advent of really practical system IC virtual prototypes and the tools to work with them portend a major shift in the electronics industry, particularly for embedded applications, away from standard ICs used as building blocks at the board level toward the more cost-effective, differentiable, system-on-a-chip ASIC. Forward-thinking semiconductor manufacturers are already moving in this direction, making processor cores and other logic blocks available to their customers together with accurate models of those cores suitable for virtual prototyping. Consequently, electronics companies are being presented with a new opportunity to distinguish themselves by taking advantage of a major technology transition or to lose out because of it.

Especially in this industry, if you're not quick, you're dead.

Tom Dille is the vice president of marketing at CAE Plus, Inc. in Austin, Texas. He has more than 18 years' experience in the electronics industry. Previously, he was the vice president of marketing and sales at Oasis Design in Austin, and prior to that the division marketing manager of the Communication Products Division of Advanced Micro Devices. He also held marketing positions at Crystal Semiconductor and Intel.

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integrated system design  May 1998