RM57L843: RM57L843 FMEDA problems

Hello Yue,

First, please consider posting future FMEDA questions in the private forum since the FMEDA is covered under NDA. However, I think for this question it is OK that we can answer simply based on the Safety Manual and TRM which are public documents.

First, the mandatory designation here means that there is really nothing for you to do and that it is automatically used. 

For SYS1 it is referring to the multi-bit keys used to enable and disable some critical features such as ECC or to enable modification of certain module configurations such as in the IOMM module and also applies to things such as servicing the internal watchdog. It is whereever the module requires multiple bits to be modified to assert or de-assert a feature/function.

For SYS4, there are some critical bits that needed to be protected from the possibility of transient faults so custom structures are used to enable ECC-like functionality on these bits. A search of the TRM for the use of High Integrity or High Reliability bits should help explain where these bits are located. The only need for the integrator to use on these bits is to handle any potential fault generated when there is an uncorrectable event. that triggers a fault.

For clarity, here is a list of registers that can be found int he TRM that are protected by the high-integrity bit implementation: