Mixed-Signal Methodology Guide: Design Management

I reviewed the book Mixed-Signal Methodology Guidein August of this year published by Cadence, and decided to follow up with one of the authors, Michael Henrie from ClioSoft, to learn more about the importance of Design Management for AMS. Michael is a Software Engineering Manager at ClioSoft and has worked at Zarlink Semi, Legerity, Agere Systems and Lucent Technologies.

Why did Cadence select you to write the chapter on design management?

ClioSoft has been in the DM business since 1997 and has a large number of customers. We don’t exactly know why they picked us but we would like to think that Cadence had gotten some good feedback about us from their customer base. We pride ourselves on good customer support and try very hard to listen to our customers and provide them with solutions that enhance and streamline their processes. We hope that it is through our efforts that we were chosen to write for the book.

Is your DM solution specific to the Cadence Virtuoso flow?

No, our SOS family of DM products can be used for a variety of flows – analog mixed-signal design, digital front end, software, etc. Some of our customers use us for managing documentation and PCB data as well. DM is beneficial for any flow as it provides methods to manage any project data, not just data specific to Cadence. DM enables collaboration and provides peace of mind, assuring that users won’t accidentally overwrite each other’s work and that users can always get back old versions. In addition to Cadence Virtuoso, ClioSoft is seamlessly integrated with several EDA flows such as Mentor Pyxis and HDL Designer, Synopsys Custom Designer, and Springsoft Laker. It is our goal to make certain that all of our customers are well served no matter what flow they use. Several of our customers use multiple flows – sometimes due to acquisitions and sometimes because they want to use the best in class tools even in the same group.

Why should AMS designers use DM?

As chip sizes have grown, so have the number of contributors to a project. This has increased the difficulty in coordinating the many changes that the engineering change orders have produced. A DM system such as SOS helps in many different ways such as:

• Makes sure that users don’t accidentally overwrite each other’s changes.
• All changes are versioned and users can easily revert back if needed.
• Keeps a full audit and history of changes so teams members know exactly who made what changes, when and why.
• Makes sure that engineers have real time access to all changes made irrespective of which site the changes were made.
• Keeps track of exact project configurations and milestones so they can be easily recreated if needed.
• Allows tape out with confidence, since engineers know that they did not leave behind that critical last minute fix.

What are some of the important requirements for a DM system for designers?

Designers work with development tools at an abstract layer of the data where they are dealing with logical objects like schematics and layout that made up of multiple physical files. Design tools often produce a large number of large files. Additionally, designers must be able to collaborate with each other — both locally and remotely — to share their changes. A DM systems should meet a few minimum requirements:

• Be easy to use and setup. If not, it will either not be used or be used incorrectly, which can be even worse.
• Be seamlessly integrated with the EDA flow so designers can work with logical objects in their familiar design environment.
• Handle large volumes of often binary data and allow multiple sites to collaborate and share data efficiently.

ClioSoft SOS integrated in Cadence Virtuoso Schematic

Why can’t they just use a software configuration management system like CVS, SVN, Clearcase or Perforce?

SCM systems are designed to manage software code which is typically in text format and smaller in size. SCM systems aren’t optimized to handle large binary data found in hardware development. For instance, every user gets a physical copy of all the files in the project in their workspace and this is both inefficient and expensive, especially for large teams. Additionally, SCM tools aren’t integrated into EDA flows and do not handle the mapping from logical design units to physical files. With an SCM system you could only tell that two versions of a schematic are different. With ClioSoft’s HCM you can actually do a visual diff of schematics or layouts and see exactly what changes were made between different versions highlighted directly in the editor. Typically, SCM systems are quite complex, providing features for concurrent development that are not relevant for design teams that deal with binary files that are not amenable to concurrent changes.

Visual Design Diff

What is your advice to designers?

Take advantage of DM to improve the collaboration across your team, to remove the worry of your data being lost/corrupted/damaged/overwritten. One of our customer’s layout managers came to our booth at a trade show recently and made the admission that he was one of the people vehemently opposed to deploying SOS and now one year later he was glad that he was overruled. Now he wonders how they ever managed to collaborate across three different sites and get their work done without SOS! Design teams are often reluctant to make changes but deploying a DM system is well worth the investment and can save you both time and potentially very expensive re-spins.

Where can I read the chapter on Design Management?

You can get a PDF on that chapter on Design Management, plus enter the drawing for the book here.

Also Read

AMS IC Design at Rohde & Schwarz

EDA User: Rafaela Novais from TowerJazz Semi

Mixed-Signal Methodology Guide