3.4. How to improve the wake-up from Stop sequences without relying on the global SystemClock_Config()

The provided SystemClock_Config() example is intended for startup clock configuration. It is not recommended to use it to restore clock settings after a Stop mode.

To keep wake-up as quick as possible, restore only what the hardware changed. Typically, after a Stop mode, it is recommended to call a separate SystemClockConfig_STOP() after the wake-up.