Functional safety standards are tightening as designs for the automotive and safety markets become richer, more autonomous and, of course, more complex. Legacy elements of system present a major challenge here, as seeking to ‘upgrade’ them can often prove to be an error-prone process.
A new technical paper discusses this and other aspects of delivering a functional safety methodology that is compliant with the Failure Mode Effect and Diagnostic Analysis (FMEDA) of the ISO 26262 standard for the automotive market.
For designs to satisfy the target Automated Safety Integrity Level (ASIL) under FMEDA, it describes a process with four core processes:
- Explore areas of the design where better fault detections are needed.
- Introduce safety mechanisms that have the right tradeoff for the RTL structures.
- Validate the design changes with sequential logic equivalence checking (SLEC).
- Inject faults with a formal verification-based methodology to measure the diagnostic coverage.
Each of these steps is described and then illustrated by way of a sample case study that considers the implementation of a memory subsystem within an AMBA-based design.