Hello,
It seems some modules in the FMEDA were hidden because of an active filter on the report worksheet. When regenerating the report without the filter the other latent mechanisms are very well visible. The metric numbers remain the same and are inline nonetheless.
Yes the metrics quoted by David are the ones after removing only the Scheck and Sboot safety mechanisms.
Since you've mentioned your target ASIL as ASIL B we can further recalculate the metric with the split lock configuration of the M7 cores. However since the chip targets an ASIL D metric the rest of the architecture and the coverages provided by a majority of the safety mechanism remain the same even in the split lock or ASIL B configuration. Therefore even in the split lock configuration the metrics fall only slightly. The Latent fault coverages provided by the other latent safety mechanisms also remain the same. This explains why we can see more than sufficient metric targets being met in spite of removing schecks and sboot from the FMEDA.
However please refer my other response in the thread regarding the importance of implementing latent fault checks (scheck and sboot). Quoting it below for reference.
"However please be aware that it’s the system integrator's responsibility to implement latent checks if they choose not to implement our SAF modules (Schecks) irrespective of whether or not the FMEDA meets the metrics with these checks deactivated. FMEDA is only a verification step to ensure we are meeting the metric and not a tool to define the safety concept/architecture. We do not recommend to remove some tests just to achieve coverage numbers because the absence of some tests may result in comprise of the safety of the device/system. Also the system integrator is responsible to justify the changes during assessments/audits.
The FMEDA assumes that SM2 are implemented. Here as well, we recommend to not disable SM2."
Hope this helps!
Thanks!
-Yashwant
