Issue 109, August 1999
Using System-on Chip Design with Virtual components

Start • Forms of VC • VC Functions • Using a Virtual Component • Multiple VC Applications • VC Verification Issues • VC Test Challenges • Cores in FPGA Devices • Works in Progress • References • Sources

Design reuse for semiconductor projects has evolved from an interesting concept to a requirement. Today’s huge system-on-a-chip (SOC) designs routinely require millions of transistors. Silicon geometry continues to shrink and ever-larger chips are possible.

But, the enormous capacity potential of silicon presents several challenges for designers. Design methodology and EDA tools are being severely stressed by SOC projects at the same time that narrowing time-to-market requirements demand more rapid and frequent introduction of new products.

SOC projects present another problem—how to design enough logic to fill up these devices. Few companies have the expertise to design all the intellectual property (IP) needed for a true SOC, and few have enough engineering resources to complete such a massive project. Even those with the required knowledge and plentiful resources may still be unable to finish a complete chip design in time to meet accelerated market demands.

The net result: SOC projects require design reuse. Only by leveraging off past designs can a huge chip be completed within a reasonable time. This solution usually entails reusing designs from previous generations of products and often leverages design work done by other groups in the same company.

Various forms of intercompany cross licensing and technology sharing can provide access to design technology that may be reused in new ways. Many large companies have established central organizations to promote design reuse and sharing, and to look for external IP sources.

One challenge faced by IP acquisition teams is that many designs aren’t well suited for reuse. Designing with reuse in mind requires extra time and effort, and often more logic as well—requirements likely to be at odds with the time-to-market goals of a product design team.

Therefore, a merchant semiconductor IP industry has arisen to provide designs that were developed specifically for reuse in a wide range of applications. These designs are backed by documentation and support similar to that provided by a semiconductor supplier.

The terms "virtual component" and "core" commonly denote reusable semiconductor IP that is offered for license as a product. The latter term is promoted extensively by the Virtual Socket Interface (VSI) Alliance, a joint effort of several hundred companies to set standards for VC design, verification, and use. In this article, I describe the major virtual component (VC) types and discuss their use in SOC designs.