Applicability - Safe processing Safety Function in Safety Manual Addendum

[FabioG]

Hi there, 

In safety manual's Addendum, in Tab "Module classification" there is a column named: 

"Applicability - Safe processing Safety Function". 

The legend says: "x Identifies the safety function in which the SR element is used...."

1)I didn't find in manual any definition of Safety Function: could you explain?

2) what is the difference beetween SF and Safety Mechanisms ?

3)  shall I implement any software for safety functions in which a particular module (SafetyRelevant) is used?

4) for example: in category "Reset and Boot", modules DCM and DCF are not safety mechanisms but they are Safety functions-related. The question are:

 a) shall I implement any software?

b) if yes, what kind of funcionality ?

c) is that funtionality present in safety manual or in other NXP documentation?

Best Regards

Fabio

[antoinedubois · Accepted solution]

Hello Fabio, sorry for the delay.

1) Safety Function is a function that if a failure happens and without safety feature would violate the safety goal. it is usually for Microcontroller a subfunction of the "Safe compute function" for each we derive our safety concept.

2) SF Safety functions failure directly violate the safety goals. A SF is considered a potential SPF. SM are the HW diagnostic that detects failure, they usually contributiing to the Latent fault metrics.

3) The SF is what you consider Safe and that you need to protect. It should include your Safety related SW that is implemented within the "Sae Compute function).

4) If DCM or DCF fails we have analyzed tthat it could violtate the safety goals. You can look in the FMEDA and review what Safety mechanisms we consider to detect/prevent the failures. If anything needs to be implemented it would then be explained in the Assumptions of Use. SO you mostly need to implement the assumptions of use for DCM and DCF.

I hope it helps.

Antoine Dubois