Table 16.259. 0x072F DSPLL D Holdover History Average Length
Reg Address
Bit Field
Type
Setting Name
Description
0x072F
4:0
R/W
HOLD_HIST_LEN_
PLLD
5- bit value
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. See to calculate the window length from the register value. time = ((2
LEN
) –
1)*268nsec
Table 16.260. 0x0730 DSPLLD Holdover History Delay
Reg Address
Bit Field
Type
Setting Name
Description
0x0730
4:0
R/W
HOLD_HIST_DE-
LAY_PLLD
5- bit value
The most recent input frequency perturbations can be ignored during entry into holdover. The holdover logic pushes back into the past.
The amount the average window is delayed is the holdover history delay. See to calculate the ignore delay time from the register value.
time = (2
DELAY
)*268nsec
Table 16.261. 0x0732
Reg Address
Bit Field
Type
Setting Name
Description
0x0732
4:0
R/W
HOLD_REF_COUN
T_FRC_PLLD
5- bit value
Table 16.262. 0x0733-0x0735
Reg Address
Bit Field
Type
Setting Name
Description
0x0733
7:0
R/W
HOLD_15M_CYC_
COUNT_PLLD
Set by CBPro.
0x0734
15:8
R/W
HOLD_15M_CYC_
COUNT_PLLD
0x0735
23:16
R/W
HOLD_15M_CYC_
COUNT_PLLD
Table 16.263. 0x0736 DSPLL D Force Holdover
Reg Address
Bit Field
Type
Setting Name
Description
0x0736
0
R/W
FORCE_HOLD_PL
LD
0: For normal operation
1: To force holdover
Si5397/96 Reference Manual
Si5397C/D Register Map
silabs.com
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