27 - 28 October, 2020

Virtual Conference

Event Details

MP Associates, Inc.

TUESDAY October 29, 16:00 - 17:30 | Forum 6

Tutorial 15: Revitalizing Automotive Safety Hard and Soft Error Approaches
Mark Burton - GreenSocs SAS

Ayman Muallem - Optima Design Automation
Nael Qudsi - Optima Design Automation
Habib Karam - Optima Design Automation

This tutorial is appropriate for any engineers or engineering managers concerned with automotive safety fault analysis. Optima Design Automation will explore new approaches, based on their high-performance fault simulation technology platform, for analyzing both permanent faults (or Hard Errors), together with transient faults (or Soft Errors) that have significantly improved real design flows at leading semiconductor companies. The tutorial will include the exploration of real results. Attendees will be exposed to new methods and approaches that could improve their fault analysis solutions.

Random fault analysis for safety-critical automotive semiconductors remains a laborious and difficult task. Fault analysis using current fault simulation tools simply takes too long and can result in indeterminate coverage metrics. Some fault types are hard to analyze at all.

Proving that devices meet the ISO 26262 ASIL-C/D safety tolerances has always been difficult. Using traditional fault simulation, even when augmented with formal verification tools, weeks of analysis are required to ensure that safety mechanisms eliminate a high proportion of dangerous faults.

Hard errors include permanently stuck at 1 or 0 faults, bridging faults between two signals, or tristate signals. Proving >99% of these faults either does not affect the operation or may be eliminated by safety mechanisms is required for ASIL-D certification. Achieving this level of coverage using regular fault simulation has proven extremely difficult, to the point where many organizations have given up with this requirement.

Soft errors or transient faults are even harder to analyze using these techniques. Transient faults are handled mostly by using selective hardening, where a proportion of flip-flops are altered such that they “swallow” transient errors. These hardened flops are expensive in terms of silicon area and power consumption so qualifying the design such that a minimal number of flops are hardened to achieve required coverage is important. However, this level of analysis is hard to achieve with basic fault simulation.

Optima Design Automation has taken a new approach to both hard error and soft error analysis. The company has developed a new form of fault simulation technology that provides multi-orders of magnitude performance improvement over other fault analyzers. Using this as a platform it is possible to drive more effective approaches to analyze both Hard and Soft Error faults.

This tutorial will detail how permanent and transient faults may be handled more effectively and quickly than previously possible.

For Hard Errors, the structural analysis will be performed that categorizes fault types and provides a more effective fault pruning before fault-simulation execution. The fault simulator runs and operates in a fraction of the time of previous tools. With this faster operation, it is possible to rapidly update the Software Test Library to provide more effective tests and prove out faults more quickly.

With this method, greater coverage may be achieved, but this is still potentially not to the level required. An additional coverage boosting mechanism may be employed to identify coverage holes and fill them relatively automatically.

The tutorial will also include Soft Error analysis, with the aim of producing an optimal set of flip flops to be hardened providing ASIL-D coverage with minimal power and silicon area increase. This methodology involves an iterative fault simulation process usually too expensive. However, the approach presented in this tutorial, coupled with high-performance simulation, will provide the ultimate flip-flop configuration.

The tutorial will use presentations and demonstrations. Real results from end-users will be shown alongside the tutorial sections.

The agenda:

  • The current state of the art in Automotive Safety Fault Analysis 
  • Hard Error fault detection, grading and coverage boosting
  • Soft Error analysis and selective hardening optimization
  • Real design results

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