Chip team applies Linux approach to CPU design

OpenCores' OpenRisc 1000 core to debut under GNU licence

Can open source chip hardware shake up the embedded processor market the way Linux is changing the face of the operating system business? That's the question a gang of chip designers called OpenCores will attempt to answer when it launches its free 32-bit Risc CPU core later this week.

Certainly OpenCores operates along the lines of the thousands of software coders who co-operate across the Internet to develop the Linux kernel. As Damjan Lampret, a 22-year-old computer science student at the University of Ljubljana, Slovenia and one of the OpenRisc design leaders, put it in an interview with EE Times: "We are modeling ourselves on the Free Software Foundation. We're trying to work in a similar way.

"We're not a legal entity - it's more like a club. But people are starting to work together, and some designs are already done."

Just as any PC user can download and compile the Linux kernel, chip designers will soon be able to grab OpenCores' OpenRisc 1000 design and use it as the basis for their own processors, completely free of charge. OpenCores' Web site already offers an open source OpenRisc C compiler, and full schematics and circuitry description files for the core itself will soon be available for download.

The downside is that, like Linux user in the OS' early days, chip developers are on their own - OpenCores isn't offering support. And if the OpenRisc design is released under a GNU-style licence, designers who use it will be required to release their modifications and extension under the same open source terms.

How keen chip companies are going to be to do so remains to be seen. Silicon IP has always been very closely guarded, but then so was operating system and application code until Linux came along and established the principles of open source. But while it's relatively easy for software companies to make the mental leap to realise that source code and binaries are not one and the same thing, it's going to be harder for chip designers to do the same.

Like code, a chip's design and its implementation in silicon aren't necessarily one and the same, but that's going to be hard for fabless operations - companies that don't actually make silicon - to accept.

Indeed, according to the EE Times report, ARM is already getting stroppy and predicting dire consequences for anyone who attempts to clone its cores using OpenCores' technology.

OpenCores has a version of OpenRisc that supports the MIPS-I instruction set, and while MIPS has yet to take action against the group, it has sued other chip companies who have offered products compatible with its own.

But suing companies is easy - how you take legal action against such a disparate grouping as OpenCores is another matter. By the same token, however, the loosely-coordinated nature of OpenCores doesn't exactly make for the level of quality control chip designers expect, which could easily sideline OpenRisc as little more than an academic curiosity. ®

You can read EE Times' interview with OpenCores in full here

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