Configuring TC23xL development board PLL frequency, I want to set the PLL clock source is external crystal OSC,
by reference to the UM also made reference to the inherent Boot, the VOC closed, switch to the OSC. But through a few
tests and formula for calculating PLL clock source is VOC, namely internal oscillator. It does not come out with,
please provide some help or routines, thank you. (Unlocked, locked me by calling header file related functions to achieve)