Table 2.3. Holdover Mode Control Registers
Register Name
Hex Address
[Bit Field]
Function
Holdover Status
HOLD
0x000E[5]
DSPLL Holdover status indicator.
0: Normal Operation
1: In Holdover/Free run Mode:
HOLD_HIST_VALID = 0 ≥ Free run Mode
HOLD_HIST_VALID = 1 ≥ Holdover Mode
HOLD_FLG
0x0013[5]
Holdover indicator sticky flag bit. Remains asserted after the indi-
cator bit shows a fault until cleared by the user. Writing a 0 to the
flag bit will clear it if the indicator bit is no longer asserted.
HOLD_INTR_MSK
0x0019[5]
Masks Holdover/Free run from generating INTRb interrupt.
0: Allow Holdover/Free run interrupt (default)
1: Mask (ignore) Holdover/Free run for interrupt
HOLD_HIST_VALID
0x053F[1]
Holdover historical frequency data valid.
0: Incomplete Holdover history, Free run mode available
1: Valid Holdover history, Holdover mode available
Holdover Control and Settings
HOLD_HIST_LEN
0x052E[4:0]
Window Length time for historical average frequency used in
Holdover mode. Window Length in seconds (s):
Window Length = (2
HOLD_HIST_LEN
- 1) x 8 / 3 x 10
-7
HOLD_HIST_DELAY
0x052F[4:0]
Delay Time to ignore data for historical average frequency in
Holdover mode. Delay Time in seconds (s):
Delay Time = 2
HOLD_HIST_DELAY
x 2 / 3 x 10
-7
FORCE_HOLD
0x0535[0]
Force the device into Holdover mode. Used to hold the device
output clocks while retraining an upstream input clock.
0: Normal Operation
1: Force Holdover/Free run Mode:
HOLD_HIST_VALID = 0 =>Free run Mode
HOLD_HIST_VALID = 1 =>Holdover Mode
Holdover Exit Control
HOLD_RAMP_BYP
0x052C[3]
Holdover Exit Ramp Bypass
0: Use Ramp when exiting from Holdover (default)
1: Use Holdover/Fastlock/Loop bandwidth when exiting from Hold-
over
Si5386 Rev. E Reference Manual • Modes of Operation
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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Rev. 1.2 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • December 9, 2021
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