Power Intent Formats: Light at the End of the Tunnel?

Sorin Dobre (Qualcomm), Pete Hardee (Cadence), Colin Holehouse (ARM), Minh Chau and Rolf Lagerquist (Texas Instruments)
EETimes (2/13/2012 11:40 AM EST)

Abstract

Two widely adopted formats for power intent exist: Si2’s Common Power Format (CPF) and IEEE’s Unified Power Format (UPF). The formats have been described as the “same in every intent, but different in every detail.” The IEEE’s 1801-2009 specification, colloquially known as UPF 2.0, is the extension of Accellera’s UPF 1.0 specification and is a big step forward to be a more robust power format standard. However, the industry is experiencing pain that there are multiple formats and many engineers would prefer one. The differences are widely characterized as CPF versus UPF, but this is an over-simplification. The differences go beyond syntax or even semantics; some differences are actually inherent in methodology used to capture and implement the power intent. As a result, some would question whether format convergence will ever be possible.

There are methodology differences between CPF and 1801-2009 and, due to UPF 1.0 backward compatibility, there are two methodologies within 1801-2009. As a result, the industry must address the methodology differences before any meaningful discussion can take place on power format convergence. The authors elaborate on a path to methodology convergence that involves deprecating the incompatible methodology enabled by some UPF 1.0 constructs, such as power supply net–driven power intent specification; emphasizing the “successive refinement” methodology that is enabled by new extensions in 1801-2009 and is compatible with CPF’s layered power intent specification across different abstract levels; and, as 1801 has support for hierarchical design but CPF has a more formal hierarchical design approach, including macro modeling for power intent within hardened intellectual property (IP), that can be used to extend 1801.

The immediate benefit of methodology convergence is improved interoperability between different power formats in a mixed-format low-power design flow. Over the long term, the success of methodology convergence will lead to a fast track of format convergence. Standards process can often lead to a glacial rate of progress, but we believe this time will be different as the whole industry is aligned with the same objective and goal. Significant progress is underway toward methodology convergence. After five long years, we finally can see the light at the end of the tunnel. And for once it’s not an oncoming train.

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