Can this 20~25MHz clock after start-up be used for driving USB driver?
If 20~25MHz is not large enough, can we scale the clock to 48MHz via configuring MCG_C4, but still keep running in FEI mode?
No, you can not do that. The USB clock should be 48MHz and as I had mentioned that we do not recommend to use FLL to clock the USB.
Retrieving data ...