ISL35822 Datasheet, PDF (34/75 Pages) Intersil Corporation – Octal 2.488Gbps to 3.187Gbps/ Lane Retimer

ISL35822
Table 40. PMA SERIAL LOOP BACK CONTROL REGISTER
MDIO REGISTER ADDRESS = 1.49156 (1.C004’h)
BIT
NAME
SETTING
DEFAULT R/W
DESCRIPTION
1.49156.15:13
1.49156.12
1.49156.11
1.49156.10
1.49156.9
1.49156.8
Reserved
PMA Test LP
PMA SLP_3
PMA SLP_2
PMA SLP_1
PMA SLP_0
1 = enable
0 = disable
0’h⁽¹⁾
0’b⁽²⁾
0’b⁽²⁾
0’b⁽²⁾
0’b⁽²⁾
R/W
Serial Network Test Loopback
R/W
PMA Serial Loop Back Enable for each individual
lane. When high, it routes the internal PMA Serial
output to the PMA Serial input.
1.49156.7:0
Reserved
Note (1): Loopback is from Serial I/P to Serial O/P. Recommended use for test purposes only; the lanes are swapped, and no pre-emphasis is performed.
Note (2): These values may be overwritten by the Auto-Configure operation (See “Auto-Configuring Control Registers” on page 16 and Table 92 for details).
Table 41. PMA PRE-EMPHASIS CONTROL
MDIO REGISTER ADDRESS = 1.49157 (1.C005’h)
BIT
NAME
SETTING
DEFAULT⁽¹⁾
R/W
DESCRIPTION
1.49157.15:12
1.49157.11:8
PRE_EMP Lane 3
PRE_EMP Lane 2
See Table 42 for 00’h/07’h
settings
00’h/07’h
R/W
R/W
Configure the level of PMA pre-emphasis
(if Enabled, see 1.C01B.5:2 in Table 45)
1.49157.7:4
PRE_EMP Lane 1
00’h/07’h
R/W
1.49157.3:0
PRE_EMP Lane 0
00’h/07’h
R/W
Note (1): Default values depend on setting of LX4/CX4 select LX4_MODE pin. LX4 value is shown first. The values may be overwritten by the Auto-Configure operation
(See “Auto-Configuring Control Registers” on page 16 and Table 92 for details).
Table 42. PMA PRE-EMPHASIS CONTROL SETTINGS
(1)
ADDRESS
1.C005’h
BITS 3:0
0000⁽³⁾
PRE-EMPHASIS
(802.3ak) ⁽²⁾ =
(1-V_LOW/V_HI)
0%
PRE-EMPHASIS
VALUE =
(V_HI/ V_LOW)-1
0
ADDRESS
1.C005’h
BITS 3:0
1000
PRE-EMPHASIS
(802.3ak) ⁽²⁾ =
(1-V_LOW/V_HI)
33.0%
PRE-EMPHASIS
VALUE =
(V_HI/ V_LOW)-1
0.493
0001
5.0%
0.053
1001
36.5%
0.575
0010
9.5%
0.105
1010
40.0%
0.667
0011
14.0%
0.163
1011
43.0%
0.754
0100
18.5%
0.227
1100
46.0%
0.852
0101
22.0%
0.282
1101
49.0%
0.961
0110
0111⁽⁴⁾
26.5%
30.0%
0.361
0.429
1110
1111
52.0%
54.5%
1.083
1.198
Note (1): See Figure 3 for illustration of the pre-emphasized waveform and meaning of symbols.
Note (2): This equation is the one used by the IEEE 802.3 CX4 Working Group when discussing pre-emphasis (alias Transmit equalization). The template normalization
factor of 0.69 in step 6) of IEEE 802.3akD5.3 Section 54.6.3.6 reflects 0.31 (31%) pre-emphasis according to this equation.
Note (3): This is the Default value set on power-up or RESET if the LX4/CX4 LX4_MODE pin is set for LX4 operation. This setting allows for a lowered device power
consumption by using the Lowered Power bits to turn off the pre-emphasis drivers (seeTable 45).
Note (4): This is the Default value set on power-up or RESET if the LX4/CX4 LX4_MODE pin is set for CX4 operation. This setting allows for a small loss in the PCB
traces and connectors before the IEEE 802.3akD5.3 defined TP2 compliance measurement point. The value may be overwritten by the Auto-Configure
operation (See “Auto-Configuring Control Registers” on page 16 and Table 92 for details).
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