If you select On in the Auto Return drop-down box, the system automatically returns to the original clock when proper criteria has been re-established. When Auto Return is selected, the remaining drop-down boxes are grayed out to prevent modification.
To manually select a clock:
Select Off in the Auto Return drop-down box.
Select the desired clock in the Clock Source drop-down box.
Select the desired mode in the Clock A Selected Mode drop-down box.
Select the desired mode in the Clock B Selected Mode drop-down box.
Note: Mode defines the minimum required state for a clock to be selected.
Click OK to accept changes and return to the System Configuration screen, or Cancel to return to the System Configuration screen without saving changes.