A New Era In Requirements Management

Project teams face a host of challenges when developing semiconductors compliant to a safety critical market. ISO 26262 drives state-of-the art safety critical designs for automotive electronics, DO-254 for airborne electronics hardware, and IEC61508 for industrial electronics, to name a few.

In the context of ISO 26262, much of the discussion in recent years has been on challenges addressing run time failures (random failures). But lately, the volume of chatter discussing the challenges of executing a requirements-driven lifecycle to deliver bug and defect free silicon is growing. Frankly, this isn’t surprising when looking at the latest Wilson Research Survey data.

The data suggests a convergence of scenarios ultimately driving an exponential growth in design complexity. This includes:

• 58% of designs are 10M gates or greater
• 52% of designs contain at least two processing cores
• 34% of designs contain an AI accelerator
• 80% of automotive designs contain security features
• 86% of designs have active power management

All of this supports the larger data point that 76% of ASICs will require two or more respins, a concerning trend given rising fabrication costs.

Fig. 1: Wilson Research Survey detailing number of ASIC spins before production.

As complexity rises, the probability of first silicon success lessens unless project teams evolve with new methodologies and automation, including how project teams manage requirements.

Requirements-driven development is a foundational component of any safety critical lifecycle. At face value, requirements seem like a very straightforward concept.

• Project teams write requirements
• Requirements are implemented into the product
• The product is tested to ensure the requirements have been met

Simple enough, right? Unfortunately not.

Challenges managing requirements

ISO 26262:2018-8 Clause 6 does provide guidance in managing requirements, notably around requirement notation and attributes. Even with this guidance, project teams grapple with:

• Enforcing good requirement structures to make certain they are unambiguous, comprehensible, atomic, feasible, and verifiable
• Configuring workflows that support requirement reviews, approvals, impact analysis, and more
• Capturing and decomposing requirements both within a project and across the supply chain
• Tracing requirements to lifecycle artifacts to prove the requirements are realized and verified (more on this later)

Traceability is a core component of a requirements-driven lifecycle and links a requirement to the implementation and verification evidence. It’s also a unique challenge unto itself. Audits and assessments will confirm traceability exists across multiple areas, including:

• Code
• Document
• Process
• Verification
• Reports for all standards
• And more

Figure 2 describes the traceability threads (or connection points) between requirements and artifacts. While not shown, there are implied threads between requirements when decomposition occurs.

Fig. 2: Example of requirement traceability threads.

Traceability using traditional established methods (this might include Excel, Word, task management, and solution native test management, etc.) adds significant overhead in the management of data. As the group of solution tools grows, visibility and governance are more difficult, and addressing customer and supplier demands takes more resources. Integrations, like script-based infrastructure added to support traceability, incurs additional overhead in the form of continuous maintenance. These integrations are subject to breaking as solution versions fluctuate, and this creates a significant data loss and risks design rework.

Intelligent traceability using automation

Siemens Digital Industries Software offers a suite of products tailored to supporting requirements driven flows. These products underscore the Siemens Xcelerator open ecosystem mindset by providing APIs and industry standard interfaces, and therefore offer maximum flexibility in establishing traceability across diverse toolchains. In addition to open interface support, Siemens has implemented native integration between Siemens Polarion and Questa Verification IQ.

Siemens Polarion is a complete application lifecycle management solution providing a suite of integrated application lifecycle management (ALM) modules across project management, requirements management, change and configuration management, quality management, and more.

Fig. 3: The five Polarion pillars.

Questa Verification IQ is Siemens EDA data-driven verification solution leveraging analytics and collaborative web-based technologies to deliver a new paradigm in how semiconductors are designed and verified. Verification IQ is ISO 26262 certified by TÜV Saar and pre-qualified for use within ASIL-D projects.

Fig. 4: The Questa Verification IQ platform.

Native integration between Polarion and Questa Verification IQ provides dynamic real-time linking between requirements and verification data. Once mapped, requirements are directly traced to the verification artifacts that prove that the requirement was adequately tested. This automation provides three key benefits:

• Takes the engineer out of the loop in managing requirement relationships
• Eliminates situations where requirement analysis is incorrect due to stale lifecycle data
• Enables efficient triage of incomplete requirements

Leveraging industry standard interfaces, users can dynamically view the verification artifacts from within the requirements management environment or requirements from within the Verification IQ environment. Up to date visibility is guaranteed, and the complexities surrounding data synchronization are automated behind the scenes.

Once linked, stakeholders (assessors, project leads, safety managers, etc.) can view in real time the verification status for each requirement within their preferred working environment.

Fig. 5: Bi-directional traceability between Polarion ALM and Verification IQ.

Conclusion

Project teams continue to battle against three opposing forces: rising silicon complexity, high cost of failure, and shortened development cycles. Further complicating matters is the need for efficient collaboration across disparate functions, geographies, and business units, as well as with external integrators.

One area where operational inefficiencies exist is in how project teams manage lifecycle data within a requirements-driven workflow. Busy, overpopulated solution landscapes and traditional manual methods incur unacceptable levels of overhead and must be replaced by a solution that provides full collaborative, scalable, lifecycle management and verification management in a single system. Such a solution cuts overhead and complexity.

Siemens delivers a complete set of tailored, safety critical software solutions featuring native integrations between the lifecycle management and EDA worlds. If you’d like to learn more detail about how Siemens automation addresses requirements, traceability, and the management of lifecycle data, please read our full paper, Intelligent requirements traceability for ISO 26262.