TLK3118 Datasheet, PDF (20/57 Pages) Texas Instruments – Redundant XAUI Transceiver

TLK3118
Redundant XAUI Transceiver
SLLS628A – DECEMBER 2004 – REVISED APRIL 2005
www.ti.com
V_CMT
V_od(p)
V_od(d)
V_od(p)
V_od(pd)
V_od(d)
V_od(pp)
Bit
Time
Bit
Time
Figure 19. Output Differential Voltage with 1-Tap FIR Pre-Emphasis
The 2-stage mode operates in a similar manner but considers the logic level of the previous two transmitted bits
when determined how much pre-emphasis to apply. The level and mode of the pre-emphasis is programmable
via MDIO Register bits 4/5.32900.14:11. Users can control the strength of the pre-emphasis to optimize for a
specific system requirement.
High-Speed Receiver
The high speed receiver is conformed to the physical layer requirements of IEEE 802.3ae Clause 47(XAUI),
Gigabit Ethernet, and Fiber channel 1 and 2. Register bit 4/5.32900.5 is used to switch between AC and DC
coupled at the receiver. When the receiver is AC coupled, the termination impedances of the receiver is
configured as 100Ω with the center tap weakly tied to 2×VDDT/3 with a capacitor to create an AC ground. When
the receiver is DC coupled, the common mode will be determined by both receiver and transmitter
characteristics.
All receive channels incorporate an adaptive equalizer. This circuit compensates for channel insertion loss by
amplifying the high frequency components of the signal, reducing inter-symbol interference. Setting 4/5.32900.2
will enable adaptive equalization. In this mode, both the gain and bandwidth of the equalizer with be controlled by
the receiver equalization logic. Bandwidth selection will be based on the setting applied to 4/5.32901.14:13 and
4/5.32900.3. Equalization can be disabled by setting 4/5.32900.2 low.
Loopback
Two internal loopback modes are possible for each XAUI Channel Group A and B. One, called XGMII loopback,
allows the transmit 10 bit data to be looped back to the receive 10 bit data inputs. The other, called XAUI
loopback, allows the receive XGMII data to be looped back to the transmit data path. These configurations are
listed in Table 5.
RETIM
0
1
0
0
0
4/5.0.14
0
X
1
0
0
4/5.32792.1
0
X
X
1
0
Table 5. Loopback Configuration
4/5.32792.0
0
X
X
0
1
Configuration
Transceiver Mode  Normal Operation
Retime Mode(XAUI A receiver data is routed out to XAUI B. XAUI B receiver
data is routed to XAUI A)
If configured as PHY XS, XAUI is loopback to the same channel. If
configured as DTE XS, XGMII is loopback to the same channel.
XAUI data loopback
XGMII data loopback
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