the BWx_PLLB, FAST_BWx_PLLB, and BWx_HO_PLLB parameters to take effect. Note that individual SOFT_RST_PLLB (0x001C[2])
does not update the bandwidth parameters.
Table 15.174. 0x0515-0x051B MB Divider Numerator for DSPLL B
Reg Address
Bit Field
Type
Setting Name
Description
0x0515
7:0
R/W
M_NUM_PLLB
56- bit number
0x0516
15:8
R/W
M_NUM_PLLB
0x0517
23:16
R/W
M_NUM_PLLB
0x0518
31:24
R/W
M_NUM_PLLB
0x0519
39:32
R/W
M_NUM_PLLB
0x051A
47:40
R/W
M_NUM_PLLB
0x051B
55:48
R/W
M_NUM_PLLB
The MA divider numerator values are calculated by ClockBuilder Pro for a particular frequency plan and are written into these registers.
Table 15.175. 0x051C-0x051F MB Divider Denominator for DSPLL B
Reg Address
Bit Field
Type
Setting Name
Description
0x051C
7:0
R/W
M_DEN_PLLB
32-bit number
0x051D
15:8
R/W
M_DEN_PLLB
0x051E
23:16
R/W
M_DEN_PLLB
0x051F
31:24
R/W
M_DEN_PLLB
The loop MB divider denominator values are calculated by ClockBuilder Pro for a particular frequency plan and are written into these
registers.
Table 15.176. 0x0520 M Divider Update Bit for PLL B
Reg Address
Bit Field
Type
Setting Name
Description
0x0520
0
S
M_UPDATE_PLLB Must write a 1 to this bit to cause PLL B M divider
changes to take effect.
Bits 7:1 of this register have no function and can be written to any value.
Table 15.177. 0x0521 DSPLL B M Divider Fractional Enable
Reg Address
Bit Field
Type
Setting Name
Description
0x0521
3:0
R/W
M_FRAC_MODE_P
LLB
M feedback divider fractional mode.
Must be set to 0xB for proper operation.
0x0521
4
R/W
M_FRAC_EN_PLLB M feedback divider fractional enable.
0: Integer-only division
1: Fractional (or integer) division - Required for DCO
operation.
Si5397/96 Reference Manual
Si5397A/B Register Map
silabs.com
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