4. Modes of Operation
Once initialization is complete, the DSPLL operates independently in one of four modes: Free-run Mode, Lock Acquisition Mode,
Locked Mode, or Holdover Mode. A state diagram showing the modes of operation is shown in the figure below. The following sections
describe each of these modes in greater detail.
No valid
input clocks
selected
Lock Acquisition
(Fast Lock)
Locked
Mode
Holdover
Mode
Phase lock on
selected input
clock is achieved
An input is
qualified and
available for
selection
No valid input
clocks available
for selection
Free-run
Valid input clock
selected
Reset and
Initialization
Power-Up
Selected input
clock fails
Yes
No
Holdover
History
Valid?
Other Valid
Clock Inputs
Available?
No
Yes
Input Clock
Switch
Figure 4.1. Modes of Operation
Si5397/96 Reference Manual
Modes of Operation
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