| Technology Update|
Building Productive and Predictable Design Flows
Neel Desai, product marketing manager, Synopsys, outlines Synopsys’ Lynx Design System, a production-ready design environment for faster, reduced-risk chip development.
In today’s challenging economic environment, everyone is looking at reducing costs and the semiconductor industry is no exception. But with complexity continuing to increase with each new design and project timelines getting shorter, design companies need to do a lot more with fewer resources. These pressures – reduced cost and schedule – are at odds with technology trends. With each transition to a new technology node, companies have to spend more time and money to incorporate new methodologies, techniques, tools and technologies to achieve their product goals.
To address these combined objectives, designers use a variety of automated tools to closely manage design progress including a series of design and analysis software tools. Design programs also involve an enormous range of related project management tasks including coordinating the design efforts of multiple engineers and analyzing massive amounts of data -- all with the goal of achieving the fastest, most predictable tapeout.
Synopsys has developed a highly automated environment for chip design: the Lynx Design System. Lynx helps design organizations of all sizes move to – and design at – new process nodes quickly and efficiently, with less risk and cost. It incorporates a production-proven RTL-to-GDSII design flow with features that help engineers produce fast and predictable design results. Lynx gives project managers on-demand visibility into key project metrics and simplifies and automates set-up of the flow, as well as execution and debug. In a nutshell, Lynx helps design teams efficiently manage design development and easily measure progress towards their target goals.
Figure 1. Overview of the Lynx Design System
Ready-to-go Design Flows
Designers can use Lynx ‘out of the box’ with an RTL to GDSII production flow that takes maximum advantage of the tools in the Synopsys Galaxy™ Implementation Platform. Lynx is built on the best practices and experience gained through Synopsys’ extensive interactions with leading customers, foundries and IP providers, tool specific knowledge as well as through the execution of hundreds of design projects.
Lynx incorporates the latest methodologies, including advanced low power techniques such as multi-corner multi-mode (MCMM), state-retention power gating (SRPG) and dynamic voltage frequency scaling (DVFS). The flow allows designers to easily configure, manage and execute large, complex hierarchical designs. According to Mogens Balsby, a director of product development for Oticon, "The pre-tested flows in Lynx minimize the risks associated with migrating to a new process node and enable our engineers to focus on getting the design done."
Open Architecture Eases Adoption
Synopsys has built Lynx on an open architecture, which makes it easy for design teams to configure the system to incorporate their own or third-party tools or utilities. The production flow is defined using ASCII files and the scripts are delivered as source code and written in Tcl, although designers are free to use any scripting language. Designers can define features such as script execution, tool version selection, error checking and metrics capture.
One of the challenges that design teams face is qualifying incoming technology data and IP from multiple sources. Lynx features a Foundry-Ready System that allows customers to pre-validate technology files and libraries from any foundry vendor for use in the flow. Mainstream process nodes have been pre-tested by Synopsys, enabling customers to get their production flow up and running even faster. "Being able to start the design phase with libraries and foundry data that have been pre-tested in the flow helps accelerate schedule and reduce risk", states Sujeeth Joseph, principal consultant, Wipro Technologies.
The Foundry Ready System enables designers to quickly validate incoming hard IP for use in the flow by performing standalone and interoperability testing with other IP blocks. It also incorporates process-specific checks and settings to improve manufacturability, including proven methodologies for metal fill density and on-chip variation. These features improve the quality of designs when they reach the foundry and accelerate the time to production manufacturing.
Lynx includes a Runtime Manager that automates the configuration and execution of the design flow to improve the productivity of the design team. This GUI-based application makes it easy to set up and validate design flow variables and provides an intuitive drag-and-drop interface for creating and modifying the flow. Project managers can use it to monitor one or more design blocks at the same time as they are being implemented through the design flow. "The GUI-based Runtime Manager also makes it easier to monitor and debug designs as they progress in the design flow," comments Wipro’s Joseph.
Figure 2. Runtime Manager
Designers can also use the Runtime Manager in a batch mode to automate the build of a block or the entire chip.
Another key feature of the Lynx Design System is that it shows designers and project managers how close the the design is to meeting key design goals such as power, area and timing. The Management Cockpit offers on-demand, browser-based access to important project data that Lynx captures automatically as the design progresses through the flow. An intuitive GUI-based tool for generating customized reports of the current design status against specified goals saves project managers a significant amount of effort on a regular basis collecting, collating and plotting the same data manually.
Figure 3. Management Cockpit lets designers configure, debug and monitor flows
The system tracks more than 50 metrics relating to both design characteristics and system resources at the block and chip level. Designers can track metrics such as timing, utilization, clock skew, leakage power, and fault coverage, and system resources such as runtime, CPU and memory usage. Users can also add their own metrics to the flow. Direct, easy access to key project statistics and associated trend data from any web browser helps designers and managers at all levels better predict when to expect design closure. It also enables users to maximize personnel and compute resources effectively.
The Lynx Design System includes productivity-enhancing features that help engineers to debug their flows, including:
Interaction: The designer can run tools inside Lynx and interact with it, query the database, try alternate command sequences. Designers can even step through the tool scripts by cutting and pasting, just as they do when debugging outside the Lynx environment. Being able to bring up their tools with their design in the full context of the flow makes eases debug effort.
Tracing: Lynx can output a script that is variable-free, has loops unrolled and resolves if/then statements that shows every command that was executed. This will reproduce outside of Lynx the exact command sequence the designer ran inside Lynx. The script can be executed outside of Lynx.
Upgrading the Flow
Most design teams try to avoid upgrading any flow in the middle of a design project, but there are valid reasons why this is sometimes necessary. Often it’s not an entire flow update that is required, but the ability to use new features that become available in a particular tool, for example.
While it is possible to upgrade the entire flow if necessary, Lynx allows designers to specify a tool version to be used on a task-by-task basis. It is easy to change the tool version and examine the results with a given script. Designers who want to use new command line options or features can create a local copy of the script or take the pre-defined one delivered with the new Lynx version and make it local.
The Lynx Design System speeds all stages of the chip development process (Figure 4). At the start of the project, use of validated IP, libraries and foundry technology data ensure a quick setup. The GUI-based runtime environment simplifies flow configuration, execution, and monitoring. The web-based Management Cockpit delivers on-demand visibility into key design metrics and trends to enable project transparency at all levels, and process-specific tapeout checks and settings improve the quality of foundry handoff.
Figure 4. Lynx Design System accelerates all stages of the design process
Neel Desai is product marketing manager at Synopsys for the Lynx Design System. He has over 14 years of EDA and semiconductor experience spanning both technical and marketing responsibilities. He spent 8 years as the Product Marketing Manager for Design Compiler, Synopsys flagship synthesis product. Neel received his BSEE from University of Bombay, India, his MSEE from Pennsylvania State University and his MBA from Santa Clara University.
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