S32K118 Clock Monitoring Unit Configuration

[sherifomar]

Hello,

I am working with S32K118 and I am trying to configure the clock monitoring unit according to the below steps in the manual:

However, when trying to write in any register of the clock monitoring unit such as RCCR / HTCR / LTCR / IER / GCR ,

A hard fault exception is generated and I am unable to change the registers' value at all.

Is there some protection on these registers that I have to unlock before writing?

Appreciate your kind help.

Thanks and Regards.

[sherifomar]

Hello Daniel,

Thank you so much for your answer. This was indeed the issue.

However I have another inquiry about the clock monitoring unit, I understand I can manipulate the thresholds in HTCR and LTCR registers to generate a Loss of Clock reset when monitoring the FIRC, I already tested that. But how can I change the CMU configuration to generate the same reset using the internal SOSC (8MHz) in S32K118 EVB? or does the CMU monitor only the FIRC?

Thanks and Regards,

Sherif

[danielmartynek]

Hello Sherif,

CMU does not monitor SOSC.

Section 25.2.2.4 Loss-of-clock (LOC), RM rev.9. shows how to enable the SOSC monitor. 

Regards,

Daniel

[danielmartynek]

Hello,

Have you enabled the CMU clock?

Regards,

Daniel