How to switch S32K RTC clock source to external crystal oscillator?

[kawadaxi]

Hi, Now i have a problem ,In order to ensure the accurancy of RTC, I 've used a crystal oscillator of 32.768KHZ which connected to RTC_CLKIN Pin, What puzzle me is no matter what i do to configure the clock ,it turned to be  RTC still use the LPO Clock,I don't know why ,Can somebody give me some tips ? Thanks a lot.

My Configuration as below.

1.

2.

3.

4.In addition,I have configured the PA7's mux mode to PORT_MUX_ALT4 for Enabling RTC CLK_IN.

[danielmartynek]

Hi,

The LPOCLKS register is a write-once register which is reset only on POR or LVD (Section 10.3.1.4, RM rev. 6).

Regards,

Daniel