LF RCOSC to XOSC switching during Startup.

If I plan to use an external input pin(High state) for detecting presence of XOSC (external 32.768kHz low frequency),and if the input pin is low I use internal RCOSC.Is This plan is possible ?

May I know how "if XOSC LF failure is detected then the RCOSC LF will automatically be sourced instead"?

I would like to understand where the RCOSC configured,so that it is automatically sourced.

I spoke too soon and quickly found that RCOSC LF will not be automatically sourced (default is derived from the XOSC_HF).  The clock-loss detector (see section 7.7.1.1 of the TRM) will perform a reset upon detection of losing SCLK_LF.  You can use OSCClockSourceSet to change SCLK_LF source and OSCClockSourceGet to determine if your change has taken effect.  You can refer to the Driverlib Documentation for more details.

Regards,
Ryan

I checked power policy section 6.6 in BLE Stack Developer's Guide(swru393e).

If we enable the RCOSC in the power policy,this will have any link for automatic switching from XOSC(failure detected) to internal RCOSC?

Also SWRA499.  Clock loss detection must be enabled, which will cause a reset.  The internal RCOSC can then be selected on boot after evaluating the reset source and determining that the XOSC is not well-suited for operation.

Regards,
Ryan