SNLS459 – APRIL 2011
Table 14. CTLE Settings for Adaptation
Register (Hex)
Bits 7:6 (CTLE
Bits 5:4 (CTLE
Bits 3:2 (CTLE
Bits 1:0 (CTLE
CTLE Boost
CTLE Adaptation
Stage 0)
Stage 1)
Stage 2)
Stage 3)
String
Index
40
0
0
0
0
0000
0
41
0
0
0
1
0001
1
42
0
0
1
0
0010
2
43
0
1
0
0
0100
3
44
1
0
0
0
1000
4
45
0
0
2
0
0020
5
46
0
0
0
2
0002
6
47
2
0
0
0
2000
7
48
0
0
0
3
0003
8
49
0
0
3
0
0030
9
4A
0
3
0
0
0300
10
4B
1
0
0
1
1001
11
4C
1
1
0
0
1100
12
4D
3
0
0
0
3000
13
4E
1
2
0
0
1200
14
4F
2
1
0
0
2100
15
50
2
0
2
0
2020
16
51
2
0
0
2
2002
17
52
2
2
0
0
2200
18
53
1
0
1
2
1012
19
54
1
1
0
2
1102
20
55
2
0
3
0
2030
21
56
2
3
0
0
2300
22
57
3
0
2
0
3020
23
58
1
1
1
3
1113
24
59
1
1
3
1
1131
25
5A
1
2
2
1
1221
26
5B
1
3
1
1
1311
27
5C
3
1
1
1
3111
28
5D
2
1
2
1
2121
29
5E
2
1
1
2
2112
30
5F
2
2
1
1
2211
31
As an alternative to, or in conjunction with, writing the CTLE boost setting registers 0x40 through 0x5f, it is
possible to set the starting CTLE boost setting index. To override the default setting, which is 0, set bit 3 of
register 0x2f. When this bit is set, the starting index for adaptation comes from register 0x39, bits 4:0. This is the
index into the CTLE settings table in registers 0x40 through 0x5f. When this starting index is 0, which is the
default, CTLE adaptation starts at the first setting in the table, the one in register 0x40, and continues until the
optimum FOM is reached.
Setting the Output Differential Voltage
Register 0x2d, bits 2:0
There are eight levels of output differential voltage available in the DS125RT410, from 0.6 V to 1.3 V in 0.1 V
increments. The values drv_sel_vod[2:0] in bits 2:0 of register 0x2d set the output VOD. The available VOD
settings and the corresponding values of this bit field are shown in
36
Copyright © 2011, Texas Instruments Incorporated
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