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For Soft Cores, You Need More than Synthesizable HDL Code Successful implementation requires silicon-proven cores, simulation models, a complete verification suite, and IP-conscious design tools. by Anand Naidu

The use of reusable high-level building blocks, also called cores or intellectual property (IP), is growing in popularity to help meet the time-to-market goals for electronic products. Increasing design complexity; advances in silicon technology; and the convergence of consumer electronics, computers, and communications equipment are also driving this market. According to Dataquest, the core-based, system-level IC market will be about $14 billion by 2000.

The availability of IP from independent, nonsemiconductor suppliers has had a profound effect on the semiconductor and the overall electronics industry. Although the IP market is still young, we've already seen our customers mixing IP from various sources.

For many designs, pretested soft cores, represented by HDL code, are required or desirable. Because soft cores are synthesizable, they can be modified to meet the exact needs of the application. Also, synthesizable cores can be targeted to any process technology, giving designers flexibility in the choice of a foundry and enabling them to use the most advanced process.

There are several important issues that designers need to consider when choosing a supplier of soft cores. Anyone with synthesizable HDL code for a function is in the IP business. Designers need to evaluate their options carefully. Synthesizable HDL code alone does not ensure success. Successful IP implementation requires silicon-proven cores, simulation models, a complete verification suite complying with industry standards, and IP-conscious design tools to configure and customize the cores.

A core must be silicon-proven because the main reasons for acquiring it are to reduce design risk and shorten the design cycle. It must be available in any popular HDL so that it is easy to incorporate in a high-level design methodology and integrate with the rest of the system. Since the core becomes part of a large system and is verified in the system context, it is crucial to have an accurate simulation model and an exhaustive test and verification suite. The quality of the verification test suite determines the core's quality and maturity.

If software development is on the critical path of the design, a prototyping vehicle is required so that the software development can start early. Good technical support and documentation are essential, as are very high level models of the core for the software team.

Most designers make some modification and customize cores to their requirements. Therefore tools are needed that allow designers to configure a core without becoming an expert on the IP. Such tools allow designers to enter the relevant parameters and then automatically modify the core to meet those requirements. Since the cores are complex and analyzing simulation data using traditional tools is very difficult and time-consuming, a new breed of tool is required. These IP-conscious tools enable designers to look at the relevant data, debug designs, measure performance, and help optimize the designs before fabrication.

In other words, designers need to consider more than just a synthesizable HDL model for successful soft core-based systems on a chip--much more. *

Anand Naidu is president of Sand Microelectronics Inc. (Santa Clara, Calif.).

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integrated system design  November 1997