MPC5777C STCU2 Offline BIST Result Cannot be Read

[marv_marsian]

Hello,

I have coded the STCU2 unit to offline test my MCU, however I am having issues with testing/understanding what is happening. 

I have used the records in the following excel picture. 

And I can see that the desired values are written into the correct locations, such as :

Now, when I check the EmbSys Registers tab on my S32DS ide, I found the following pictures, during pause and during run, respectively: 

During pauseDuring run

As I stated, how can I test if this is working properly? Why do I get register values as zero during pause? As far as I understand from the reference manual, 0 mean an unrecoverable fault. How does MCU work if all tests return faults?

I must add that during DCF records, I have declared all faults as recoverable.

Thank you in advance for all your helps.

Best regards. 

[petervlna]

Hello,

As I stated, how can I test if this is working properly?

BIST results are always present in STCU2 Error Register (STCU2_ERR_STAT)

Why do I get register values as zero during pause?

Not sure, this is debugger dependent. In other words, it depends on how it reads registers.

But since STCU is accessible during debug mode, I see no reason for access to be denied.

As far as I understand from the reference manual, 0 mean an unrecoverable fault. How does MCU work if all tests return faults?

BIST will fail in such case. STCU will report to FCCU that faults happen and micro will react based on FCCU configuration.

Or SW usually analyzes results of BIST and if BIST fails, SW will go into safe state (could be reset).

Best regards,

Peter

[marv_marsian]

Dear @petervlna, 

Thank you for your kind explanation. 

Then, is there a debugger that you would recommend?

Also, is there a way to corrupt the device without breaking it, such as STCU2 will detect errors during offline test? 

Thank you for your help. 

[petervlna]

Hello,

I am using Lauterbach debugger.

Also, is there a way to corrupt the device without breaking it, such as STCU2 will detect errors during offline test?

Not sure what is the purpose of this, as STCU was validated and tested in NXP factory for each chip.

But you can inject faults when you play with voltage levels on your power supply during the test.

In case you want to test only reaction path, then FCCU [NCFF] can can inject faults into ERR_STAT register of STCU.

Best regards,

Peter