Hi M J,
1) About the defauld MCG related configuration of KSDK demo , its in here "in startup -> sys_MK64F12.C".
Also, you can create a PE project ,then configuration the clock , refer to the generate code ,like this:

2) Use the KSDK driver configuration the MCG, you can refer to the "C:\Freescale\KSDK_1.1.0\doc\Kinetis SDK v1.1 API Reference Manual.pdf\34.2 MCG HAL driver" .
We can configuration the CLOCK through these two methods according to our need.
If you have any question when configuration CLOCK, welcome to the community discuss.
Best Regards,
Alice
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