Better Ways to Connect IP

By Ed Sperling

Re-usable intellectual property may sound great on paper, but actually getting pieces to be as interchangeable as Lego parts and automatically configuring them to work in a system on a chip requires more than technology. It requires a leap of faith on the part of chip engineers, and that doesn’t happen overnight.

The first step toward providing the tools was creation of the IP-XACT standard. The most recent iteration, version 1.4, was issued earlier this year. A follow-on to that standard, IP-XACT 1.5, should be finalized by late 2009 or early 2010, sources say.

IP-XACT was developed concurrently with the TLM 2.0 standard, which raises the abstraction level for system-level design. Both standards work almost like middleware, or the proverbial black-box, where you learn to use the tools rather than trying to understand all the steps in the underlying technology. The goal is to automate some of the connections that are repeated by engineers, but it also requires moving up a level of abstraction and putting faith in the companies providing the IP and the tools to make it work.

SPIRIT, the organization that is developing IP-XACT, worked in conjunction with the Open SystemC Initiative (OSCI), which developed TLM 2.0. Both were released early this year.

“TLM modeling was a key addition at multiple levels,” said Gary Delp, an LSI distinguished engineer and one of the key players in developing IP-XACT. “You can mix IP in transaction-level modeling with the RTL level. You can take named and referenced bus definitions and span abstraction levels.”

Delp said that in system-level design, automating parts of the design and specifying interfaces is critical. “Once you have standardized interfaces for re-use, it will get simpler. We are working with a team that is doing tool validation in India using IP-XACT. They found it produces such good designs that they’re requiring everyone to use it, including their customers.”

Most of the member groups that created the standard agree. John Swanson, Synopsys’ product marketing manager for Ethernet, Mobile Storage & IP Reuse Tools, calls 1.4 “a good, solid release.”

“IP-XACT 1.4 added basics for registers,” Swanson said. “When the design gets to the software debuggers you need another level of information. We’re working on the extensions now.”

Those extensions will become part of version 1.5, which will include support for automated documentation and extend the register description capability as well as implement register designs.

What it doesn’t do, however, is bridge the design worlds between hardware and software in electronic system-level design, said Johannes Stahl, VP of marketing and business development for design tools at CoWare. “Retooling of the IP model itself is way more important,” he said. “For us, SPIRIT’s usefulness is still several years out because productivity comes more from integrated environments than anything else.”

Stahl said the biggest problem in IP today isn’t interoperability and automating connections. He said the real issue is understanding how the IP blocks interact.