SI598 Datasheet, PDF (16/28 Pages) Silicon Laboratories – Programmable with 28 parts per trillion frequency resolution

Si598/Si599
Register 7. High Speed/N1 Dividers
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
HS_DIV[2:0]
N1[6:2]
Type
R/W
R/W
Bit
Name
Function
7:5 HS_DIV[2:0] DCO High Speed Divider.
Sets value for high speed divider that takes the DCO output f_OSC as its clock input.
000 = 4
001 = 5
010 = 6
011 = 7
100 = Not used.
101 = 9
110 = Not used.
111 = 11
4:0
N1[6:2]
CLKOUT Output Divider.
Sets value for CLKOUT output divider. Allowed values are [1] and [2, 4, 6, ..., 2⁷]. Illegal
odd divider values will be rounded up to the nearest even value. The value for the N1
register can be calculated by taking the divider ratio minus one. For example, to divide by
10, write 0001001 (9 decimal) to the N1 registers.
0000000 = 1
1111111 = 2⁷
Register 8. Reference Frequency
Bit
D7
D6
D5
D4
D3
D2
D1
D0
Name
N1[1:0]
RFREQ[37:32]
Type
R/W
R/W
Bit
Name
Function
7:6
N1[1:0]
CLKOUT Output Divider.
Sets value for CLKOUT output divider. Allowed values are [1] and [2, 4, 6, ..., 2⁷]. Ille-
gal odd divider values will be rounded up to the nearest even value. The value for the
N1 register can be calculated by taking the divider ratio minus one. For example, to
divide by 10, write 0001001 (9 decimal) to the N1 registers.
0000000 = 1
1111111 = 2⁷
5:0 RFREQ[37:32] Reference Frequency.
Frequency control input to DCO.
16
Rev. 1.0