The Accellera Portable Stimulus is modelled by users and tool developers with new and existing tools and methodologies to coexist.
Design and verification in electronic systems or devices need to be an integrated discipline now for the ever-growing electronic system industry. Accellera has developed the Portable Stimulus standard for portable test and stimulus for semiconductors, systems, electronic design automation (EDA) and intellectual property (IP). This enables the same specification to be reused in multiple verification languages and contexts.
While companies are working on tools in all of these coverage areas today, the problem is not fully solved. Instead, it is a continuing dialogue between users and tool developers. It requires listening to users about the problems they face so that the best long-term solutions can be found without locking down a solution based on what is available today. One way to achieve this flexibility is by mapping notions of system-level coverage into existing cover points and cover groups that can be used with existing coverage tools, as shown in Figure 1.
Figure 1: Migrating coverage data between tools.
However, there are also advantages in keeping coverage data on the graph. This will allow PS tools to control and prioritise aspects of the graphs such that the first test cases generated will be those that address the most important design targets. This makes the verification-intent model an integral part of a verification plan rather than it being loosely connected as it is today. It also enables the newly emerging tools and methodologies to coexist with existing flows and with other tools and verification performed at the block level.
The creation of the Portable Stimulus standard is a turning point for the industry, and the user community has recognised this. With many standards, users take a backseat and, while they monitor the development of the standards, they do not get actively involved. That has not been the case with Portable Stimulus, with users exerting pressure to ensure the standard goes in the directions they want, rather than taking the easy path for EDA companies based on the tools and technologies they already have. This will create a lot of innovation within the industry.
The dialogue between users, tool developers and standards bodies will continue long after the release of the PS standard. My company, Breker, has been working hard to develop definitions for system-level coverage that meet the needs of the user community, and as with much of the technology at the heart of Portable Stimulus, will share its experience with the community and continue to donate the necessary technology to drive the methodology forward.
First published by EDN.
—Adnan Hamid is the founder and CEO of Breker Verification Systems and inventor of its core technology. He has more than 20 years of experience in functional verification automation. Hamid managed AMD’s System Logic Division and led its verification group to create the first full test case generator for an x86-class microprocessor.