Si5345-44-42-D-RM
Si5342
Rev. 1.0
209
The holdover logic averages the input frequency over a period of time whose duration is determined by the history
average length. The average frequency is then used as the holdover frequency.
The most recent input frequency perturbations can be ignored during entry into holdover. The holdover logic
pushes back into the past, above the averaging window. The amount that the average window is delayed is the
holdover history delay.
Register 0x052E Holdover History Average Length
Reg Address
Bit Field
Type
Name
Description
0x052E
4:0
R/W
HOLD_HIST_LEN
5-bit value
Register 0x0531
Reg Address
Bit Field
Type
Setting Name
Description
0x0531
4:0
R/W
HOLD_REF_COUNT_FRC_PLLB 5- bit value
Register 0x0532
Reg Address
Bit Field
Type
Setting Name
Description
0x0532
7:0
R/W
HOLD_15M_CYC_COUNT_PLLB Value calculated by CBPro
0x0533
15:8
R/W
HOLD_15M_CYC_COUNT_PLLB
0x0534
23:16
R/W
HOLD_15M_CYC_COUNT_PLLB
Register 0x052F Holdover History Delay
Reg Address
Bit Field
Type
Name
Description
0x052F
4:0
R/W
HOLD_HIST_DELAY
Register 0x0535 Force Holdover
Reg Address
Bit Field
Type
Name
Description
0x0535
0
R/W
FORCE_HOLD
0 for normal operation
1 for force holdover