Table 16.219. 0x062C DSPLL C Holdover Control
Reg Address
Bit Field
Type
Setting Name
Description
0x062C
0
R/W
HOLD_EN_PLLC 0: Holdover disabled
1: Holdover enabled
0x062C
3
R/W
HOLD_RAMP_BYP
_PLLC
Must be set to 1 for normal operation.
0x062C
4
R/W
HOLDEX-
IT_BW_SEL1_PLL
C
0: Use Fastlock bandwidth for Holdover Entry/Exit (de-
fault)
1: Use the normal loop BW when exiting from holdover
0x062C
7:5
R/W
RAMP_STEP_IN-
TERVAL_PLLC
Set by CBPro.
Table 16.220. 0x062D
Reg Address
Bit Field
Type
Setting Name
Description
0x062D
1
R/W
HOLD_RAMP-
BYP_NOH-
IST_PLLC
Set by CBPro.
Table 16.221. 0x062E DSPLL C Holdover History Average Length
Reg Address
Bit Field
Type
Setting Name
Description
0x062E
4:0
R/W
HOLD_HIST_LEN_
PLLC
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 16.222. 0x062F DSPLLC Holdover History Delay
Reg Address
Bit Field
Type
Setting Name
Description
0x062F
4:0
R/W
HOLD_HIST_DE-
LAY_PLLC
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 16.223. 0x0631
Reg Address
Bit Field
Type
Setting Name
Description
0x0631
4:0
R/W
HOLD_REF_COUN
T_FRC_PLLC
Set by CBPro.
Si5397/96 Reference Manual
Si5397C/D Register Map
silabs.com
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