S32K148 LPO Clock source for Watchdog, RTC. Is it reliable for long term running

[kasirajan_chellaiah]

My product have sleep mode option.  Can I use LPO Clock source for long term running in my product .I try to use these clock source in watchdog, RTC.  Is it very Reliable ?   If not , May I know the solution to the clock source for sleep mode ? 

[danielmartynek · Accepted solution]

Hi @kasirajan_chellaiah,

The LPO clock is not very precise:

The LPO can be trimmed (41.7.1.5 Low Power Oscillator Trim Register (LPOTRIM)).

However, one step of LPOTRIM[4:0] gives about 3kHz difference in the LPO frequency.

So, the RTC won't be precise.

If you need the RTC to be precise, you would need to use RTC_CLKIN.

Regards,

Daniel