There are two automatic input selection modes that can be set by register: Auto Revertive and Auto Non-Revertive.
- Auto Revertive: In this mode, the DPLL automatically selects the valid
input with the highest configured priority. If a clock with higher priority
becomes valid, the DPLL automatically switches over to that clock
immediately.
- Auto Non-Revertive: In this mode, the DPLL automatically selects the
highest priority input that is valid. If a higher priority input because valid,
the DPLL does not switch over until the currently selected input becomes
invalid.