S32K144 - FTMs SYS-CLK - Clock drift

[kevin_bernard]

Hi Safety Team,

I have some questions concerning the clock frequencies synchronization inside the modules in the MCU.

In the "NOTE" section of the chapter 47.5.31 of the reference manual (S32K-RM rev.14), it indicates that "the GTB (global time base) feature does not provide continuous synchronization of FTM counters, meaning that the FTM counters may lose synchronization during FTM operation". I understand the purpose of the GTB, which is to start several FTM modules at the same time, but I would like to know if I do not do any FTM operation (e.g. counter reset), will my counters stay synchronized.

The question behind this is: - is it guaranteed that between two FTM modules, the FTM clocks (which is SYS_CLK) are at the exact same frequency ? no frequency drifts between the two FTMs ?

I could understand a phase jitter between the two clocks but, since the two modules receive the same master clock (SYS_CLOCK), I would be surprised if there can be a frequency drift.

Best regards,

Kevin Bernard

[kevin_bernard]

Hi NaveenM,

Thank you for your reply.

I already posted this question trough the NXP support portal and I was advised to post it in the SafeAssure community. This is why it ended up here.

Have you already moved it to the product group ? where can I find it ?

Regards,

Kevin Bernard

[naveenm]

Hi Kevin,

I moved it to S32K product group.

https://community.nxp.com/t5/S32K/S32K144-FTMs-SYS-CLK-Clock-drift/td-p/1474352

Regards,

NaveenM

[naveenm]

Hi,

Primarily, SafeAssure community is intended to support Safety related queries. This question appears to be functional/architectural, therefore moving it to product group.

Regards,

NaveenM