DE5-NET
User
Manual
64
June 20, 2018
Table 5-1
Si570 Register Table
Register Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
7
High
Speed/N1
Dividers
HS_DIV[2:0]
N1[6:2]
8
Reference
Frequency
N1[1:0]
RFREQ[37:32]
9
Reference
Frequency
RFREQ[31:24]
10
Reference
Frequency
RFREQ[23:16]
11
Reference
Frequency
RFREQ[15:8]
12
Reference
Frequency
RFREQ[7:0]
135
Reference
Frequency
RST_REG NewFreq Freeze
M
Freeze
VCADC
RECALL
137
Reference
Frequency
Freeze
DCO
lists the register settings for some common used frequency.
Table 5-2 Si570 Register Table
Output
Frequency
(MHz)
HS_DIV
HS_DIV
Register
Setting
NI
NI
Register
Setting
REF_CLK
Register
Setting
100
9
101
6
0000101
02F40135A9(hex)
125
11
111
4
0000011
0302013B65(hex)
156.25
9
101
4
0000011
0313814290(hex)
250
11
111
2
0000001
0302013B65(hex)
312.5
9
101
2
0000001
0313814290(hex)
322.265625
4
000
4
0000011
02D1E127AF(hex)
644.53125
4
000
2
0000001
02D1E127AF(hex)