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Hope fades for IC power standards union

Posted: 23 Mar 2007 ?? ?Print Version ?Bookmark and Share

Keywords:Common Power Format? Unified Power Format? IC power standards?

With new developments in the IEEE and the Silicon Integration Initiative (Si2), it now appears that a hoped-for-convergence between two rival IC low-power specifications will not take place anytime soon.

"For a paper spec convergence, I think it is probably too late," said Steve Schulz, Si2 president. "It just doesn't seem possible. I think the best thing is to let this play itself out on the marketplace." But the Si2 Common Power Format (CPF) and the Accellera Unified Power Format (UPF) will ultimately converge, he said. "I don't think the two formats will continue independently in the marketplace for very long."

Both UPF and CPF allow users to specify power intent and constraints throughout the RTL-to-GDSII design flow, and use very similar approaches to do so. The CPF, developed by Cadence Design Systems and managed by the Si2's Low Power Coalition (LPC), became publicly available in early March.

UPF is a rival effort backed by Synopsys, Mentor Graphics, and Magma Design Automation. It was released as an Accellera standard in late February. An IEEE low-power study group arose from the UPF effort, and it has requested the CPF copyright from Si2 so it can converge the two formats into one.

News came earlier this week that the IEEE Design Automation Standards Committee (DASC) has agreed to sponsor the study group's project authorization request (PAR) to become a formal IEEE working group, subject to approval by the IEEE's New Standards Committee (NesCom). The study group, now known as IEEE P1801, is forging ahead with a proposed IEEE standard for a low-power design description format.

Cadence, however, wants the CPF/UPF convergence to take place through the Si2 LPC's Comparison Work Group, which has completed an evaluation of the two formats. An e-mail reportedly sent to members of the IEEE NesCom states that Cadence has "extreme reservations" about the IEEE P1801 group and believes that granting the PAR would be detrimental to the industry.

Members of the LPC decided last week to not transfer the CPF copyrights to the IEEE. They did unanimously pass a motion stating that "the LPC desires convergence of CPF with the activity in IEEE P1801, and will support all efforts to enable this convergence." But that motion passed only after an amendment to transfer the CPF copyright was removed from the original motion.

Cadence believes that Accellera and Si2 should reach convergence first, and only then go to the IEEE for standardization, said Pankaj Mayor, group director for industry alliances at Cadence. "When we look at the current [P1801] setup, it looks like UPF backers who are trying to misuse the IEEE process to distract people away from the real issue," he said. "These people are trying to slow down their own installed base from looking at Cadence products which are ahead of their own."

Cadence is arguably ahead of UPF backers on the implementation front. In January, Cadence rolled out a low-power IC design flow that incorporates CPF into many of its products.

Cadence has also stated that the Si2's intellectual property (IP) protection process is superior to that of the IEEE. Mayor noted, however, that a new patent protection policy initiated by the IEEE Standards Association (IEEE-SA) is a "very good move." And he said Cadence will support an IEEE low-power standard "at the right time," although turning CPF over to the IEEE would have to be a collective decision of the LPC.

With the current LPC structure, all 18 members, including Cadence, would have to agree to transfer the CPF copyright to the IEEE. But a number of LPC members, not just Cadence, were nervous about the transfer, Schulz said. Cadence didn't single-handedly block the transfer, he said.

"Member companies felt they needed to focus on technical progress to advance low-power design flows, and they felt that the most efficient way they could do that is to keep the focus on things under their direct control," he said. Further, Schulz said, LPC members were uneasy about getting their legal departments to authorize a change in the LPC membership agreement that would be needed for the release of CPF.

CPF could go to the IEEE when the LPC members "feel comfortable with the terms of the transfer," Schulz said. "They don't want to do so under a pointed gun, they want to take their own time."

"We have the greatest respect for the IEEE, we support the IEEE, but it is not set up to be a convergence body," Schulz said.

LPC members include AMD, Apache Design Solutions, ArchPro, ARM, Atrenta, Azuro, Cadence, ChipVision, Freescale, Golden Gate Technology, IBM, Intel, LSI Logic, NXP, Sequence Design, STMicroelectronics and Virage Logic.

The LPC also voted last week to make the results of the Comparison Work Group publicly available, and to confirm the approval and release of CPF 1.0. The LPC has also adopted a roadmap for "XPF," an extended power format that would, hopefully, someday represent a converged power standard.

- Richard Goering
EE Times

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