Table 16.251. 0x0721 M Divider Update Bit for PLL B
Reg Address
Bit Field
Type
Setting Name
Description
0x0721
0
S
M_UPDATE_PLLD Must write a 1 to this bit to cause PLL D M divider
changes to take effect.
Bits 7:1 of this register have no function and can be written to any value.
Table 16.252. 0x0722 DSPLL D M Divider Fractional Enable
Reg Address
Bit Field
Type
Setting Name
Description
0x0722
3:0
R/W
M_FRAC_MODE_P
LLD
M feedback divider fractional mode.
Must be set to 0xB for proper operation.
0x0722
4
R/W
M_FRAC_EN_PLL
D
M feedback divider fractional enable.
0: Integer-only division
1: Fractional (or integer) division - Required for DCO
operation.
0x0722
5
R/W
Reserved
Must be set to 1 for DSPLL D
Table 16.253. 0x0723 DSPLL D FINC/FDEC Control
Reg Address
Bit Field
Type
Setting Name
Description
0x0723
0
R/W
M_FSTEP_MSK_P
LLD
0: To enable FINC/FDEC updates
1: To disable FINC/FDEC updates
0x0723
1
R/W
M_FSTEPW_DEN_
PLLD
0: Modify numerator
1: Modify denominator
Table 16.254. 0x0724-0x072A DSPLLD MD Divider Frequency Step Word
Reg Address
Bit Field
Type
Setting Name
Description
0x0724
7:0
R/W
M_FSTEPW_PLLD 56-bit number
0x0725
15:8
R/W
M_FSTEPW_PLLD
0x0726
23:16
R/W
M_FSTEPW_PLLD
0x0727
31:24
R/W
M_FSTEPW_PLLD
0x0728
39:32
R/W
M_FSTEPW_PLLD
0x0729
47:40
R/W
M_FSTEPW_PLLD
0x072A
55:48
R/W
M_FSTEPW_PLLD
The frequency step word (FSTEPW) for the feedback M divider of DSPLL D is always a positive integer. The FSTEPW value is either
added to or subtracted from the feedback M divider Numerator such that an FINC will increase the output frequency and an FDEC will
decrease the output frequency. See also Registers 0x0716–0x0720
Si5397/96 Reference Manual
Si5397C/D Register Map
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