Problem with FCCU fault injection

[yixinwu]

Hello Community,

I have got a problem with FCCU fault injection.

The FCCU can be configured as the guide described. The reaction of all faults has been set as no reaction. Then I make a fault injection of NCF[7] and no reset is done. The corresponding fault bit in NCF_S0 can be read. It works well.

Then the reaction for the fault NCF[7] has been set as short functional reset. (Only reacts if fault 7 occurs. The other faults won't trigger a reset.) I make a fault injection of NCF[7] and a reset can be observed. It works well.

The FCCU configuration remains unchanged. I make a fault injection of NCF[10] for example but a reset can also be observed. There should be no reset cause no reaction is set for NCF[10]. Why do I always get a reset, no matter which fault is injected, although no reaction has been set for this fault?

Here is my configuration:

and code for fault injection:

Thank you in advance for help!

[petervlna · Accepted solution]

Hi,

Because your reset on NCF[10] is coming from FOSU and it is a destructive reset.

Not FCCU itself.

FOSU is enabled by setting any bit of NCF_E and correspondingly same bit in any of the NMI_EN, IRQ_ALARM_EN, EOUT_SIG_EN or NCFS_CFG.

Peter

[yixinwu]

Thank you for the quick reply.

I have read the chapter 69.7 in the user manual. The mechanism of FOSU means, no matter which reaction for which error is configurated, FOSU will trigger a reset for any fault in FCCU because the 'do nothing' input from FCCU is not asserted? And this FOSU seems not to be disabled?

If I just want to get an alarm for a fault, I should stop the FOSU internal timer by doing following from FCCU according to user manual:

1.Reset: Long or short functional reset

2.IRQ: NMI or Alarm

3.Error out triggered (by FCCU or by SW)

The first one is clear and it is the option which I don't want. The second means the register of FCCU_NMI_EN or FCCU_IRQ_ALARM_EN can be configurated. This has been tested and it works. What is the meaning of the third option?

Thank you.

[petervlna]

Hi,

It means exactly whats its name is.

It is a signalization via FCCU fault pins to outside world that fault has occurred.

Peter

[yixinwu]

Ah ok.

I thought the error out is always triggered by FCCU automatically. How is the case that it is not done by FCCU but by SW?

[petervlna]

Hi,

It means exactly what its name is.

SW -> user has to signal out fault - not done by FCCU HW.

Peter

[yixinwu]

Thank you very much for the support.