S32K148 Safety Manual Diagnostics + SCST - Execution Power Mode

[hochs2]

We have a collection of diagnostics required to run at a vehicle key off event. We need assistance determining the feasibility of this for some specific safety manual diagnostics and the SCST library. 

Whenever a vehicle key off event happens, our ECU will transition from normal mode to low power mode (not reset).

Collection of diagnostics required to run upon this transition:

• ADC SM_130 & SM_204 
• Structured Core Self Test items (entire library) 

[nxf65498]

Hi Hochs2,

We would like to know the below mention diagnostic you would like to run on:

before S32K148 enters into low power mode or when S32K148 entered low power mode

Best regards,

Bhavik 

[hochs2]

Bhavik,

We need to run these diagnostics just before entering the low power mode.

Thank you,

Hunter

[nxf65498 · Accepted solution]

Hi Hunter,

Assuming the chip is in run mode while executing diagnostic you mentioned above. We recommend not to voilate FTTI timing for your application. In other words, the diagnostic must complete without failure before the ECU moves to low power mode.

Best regards,

Bhavik   

[hochs2]

@nxf65498 

The implementation hint for SM_130 says,

"Implementation hint: After reset, but before executing any safety function, the
following software tests of one or both ADC modules may be executed by the application
software to detect faults:
• ADC_SWTEST_TEST1"

Does this mean this SM diagnostic needs to run ONLY after a microcontroller reset? What would happen if we executed this diagnostic without any microcontroller reset?

[nxf65498]

Hi,

All the SM diagnostics are required to be run at start up (after MCU reset and before executing safety function) to ensure integrity of safety mechanism. If SM diagnostic are run in parallel to safety function execution then we can't guarantee the integrity of SM and it availability to react on fault occurrence. 

Please note SM means safety mechansim.

best regards,

Bhavik Vakhariya