S32G3 SAF - sBoot Destructive Count value

[SHIVRAJ]

Hi,
I was working on SAF for S32G3 and while analyzing the sBoot, I had a query regarding the Destructive Count.

I wanted to know on what basis/parameters is the Destructive Count for sBoot decided? Is it decided based on system ASIL, watchdog counters or any specific document is to be referred?

Thank you in advance

[SHIVRAJ]

Hi @chenyin_h ,

I’m currently working on S32G3 platform for an ASIL-C automotive project with an FTTI of 50 ms.

In the SAF implementation, we have tentatively kept the Functional Reset Count at 15 (default). For the Destructive Reset Count, we are currently assuming a value of 6.

Could you please advise if this value is appropriate and how it can be justified? If not, could you guide me on which parameters (such as ASIL, FTTI, etc.) should be considered to determine the correct value?

Thanks in advance!

[chenyin_h]

Hello, @SHIVRAJ 

Thanks for you reply.

Generally, the reset status is safe from safety view, so you need to determine the count based on your own software application.

There is a corresponding module for each reset source, the module will be regarded as permanent corruption when there are many resets triggered by the module, then you could determine the count based on the accepted fault times.  

There is no specific rule to determine the reset escalation count, there are not recommended values provided regarding to the topic, the users may determine it directly based on their design.

I apologize for your inconvenience.

BR

Chenyin

[chenyin_h]

Hello, @SHIVRAJ 

The value of 'Functional' Reset Escalation Threshold is set via the corresponding register as follows:

It is said that the last 4 bits represents for the value set, 0 is to disable, 0b0001~0b1111 means the the numbers set, so that only at most 15 could be set.

BR

Chenyin

[chenyin_h]

Hello, @SHIVRAJ 

Thanks for your reply.

The 'functional' reset count is used to do escalation to a 'destructive' reset, which is associated with the FRET register, there is only 4bits used for setting this, thus the maximum count is 15(0xF)

BR

Chenyin  

[SHIVRAJ]

Thank you for the reply!

But could you provide details on what factors it is to be decided? Is it dependent on ASIL of the system or the Watchdog Timer ?

[chenyin_h]

Hello, @SHIVRAJ 

Thanks for your post.

May I know if you are interested in the value set for destructive reset counter or else? referring the following from sBoot or?

Thanks for providing more information of it.

BR

Chenyin

[SHIVRAJ]

Hi,

I was looking for the value to configure for Destructive Reset. (The functional reset count is suggested as 15)