FEMDA Customized to output the data on each element

[b51447]

I am working with my customer on the S32K148 functional safety and need you great support on the two questions below.

The first question:

My customer is doing the system FMEDA calculation, and need complete information for Flash and SRAM, please check if you could provide:

1. Base failure rate and failure mode distribution for each element within Flash / SRAM;

2. Independent DC for each safety mechanism (for SP and MP) regarding each failure mode of each element;

The second question:

If customer only use 512K flash on S32K148. I need to help to modify the Memory of used to 28%. Do I need to modify the dangerous failures? The dangerous failure is related to the memory used or it is just an assumption of the possibility  on the failure cause dangerous?

[aarul]

Hello Remi

For your first query:

1. In the customer FMEDA, the failure modes are listed. Also, the total of safety related failure rate is provided for each FMEDA. A customer can add  the three column (Lamda_SPF+RF, Lambda_MPF_detected, Lambda_MPF_undetected) to get safety related failure rate. Note that this is not exactly the base failure rate but we think this should be sufficient information for a customer to carry out FMEDA activities at their end.

2. The DC claimed for each safety mechanism is also listed in the customer FMEDA. You may also want to review the Safety Analysis reports that explain the Safety Mechanisms and their coverage claimed in more detail.

For your second query:

1. "Memory used" is the amount of memory used for safety application. This implies that if there is a failure in the other 72% of memory, there will be no violation of safety goal.

2. "Dangerous Fraction" is the percentage of failures within the "Memory used" that will not cause a failure. This is due to cases within safety application where full memory allocated to safety application is not used.

Hope this answers your query.

Please ensure that the dynamic FMEDA is configured for customer usecase and a static version is generated as customer deliverable and delivered to customer along with review report from NXP safety team.

Regards

-Aarul