10.3.6.4 During Holdover
PLL1 is run in open-loop mode:
- PLL1 charge pump is set to TRI-STATE.
- PLL1 DLD is unasserted.
- The HOLDOVER status is asserted.
- During holdover, if the PLL2 was locked prior to entry of holdover mode, PLL2 DLD continues to be asserted.
- LOS engine searches for active input clock.
- PLL1 attempts to lock with the active clock input.
The HOLDOVER status signal can be monitored on the Status_LD1 or Status_LD2 pin by programming the PLL1_DLD_MUX or PLL2_DLD_MUX register to Holdover Status.