Nitin
32kHz RTC can only be used by the FLL (not by the PLL, because its value is too low for the PLL's minimum input of 2MHz).
The highest FLL factor is 2929, which limits the speed to 32768 x 2929 = 95.977472MHz
When using the FLL the USB clock should be either from IRC48M (suitable for device mode but not host) or from an external source since the FLL output is not suitable for USB (high jitter which doesn't fulfil the USB specification).
Regards
Mark
Kinetis: µTasker Kinetis support
K64: µTasker Kinetis FRDM-K64F support / µTasker Kinetis TWR-K64F120M support
For the complete "out-of-the-box" Kinetis experience and faster time to market