CertusPro-NX SerDes/PCS Usage Guide
Preliminary
Technical Note
102
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FPGA-TN-02245-0.81
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Table 11.2. GigE Configuration and IDLE Ordered Sets Definition
Configuration/IDLE
Code
Ordered Sets
Number of Code
Encoding
Configuration
/C/
/C1/
Configuration 1
4
/K28.5//D21.5//Config_Reg/
/C2/
Configuration 2
4
/K28.5//D2.2//Config_Reg/
IDLE
/I/
/I1/
IDLE 1
2
/28.5//D5.6/
/I2/
IDLE 2
2
/28.5//D16.2/
There is no specific requirement for GigE on AC-coupling or DC-coupling implementation. CertusPro-NX SerDes/PCS
supports both AC-coupling and DC-coupling link. A 100 nF AC-coupling capacitor is recommended to be used in an AC
coupled link.
XAUI Mode
The XAUI mode of CertusPro-NX SerDes/PCS is intended for the optional interface specified by IEEE802.3 between 10G
Ethernet MAC and PHY. In XAUI mode, CertusPro-NX SerDes/PCS is configured as four 2.5Gbps lanes based on 8B/10B
PCS. With Lattice XAUI IP core, the XAUI mode of CertusPro-NX SerDes/PCS fully supports from serial I/O to the XGMII
interface.
In XAUI mode, the transmit state machine inside 8B/10B PCS performs translation of XGMII idles to proper ǁAǁ, ǁKǁ, and
ǁRǁ ordered sets according to the IEEE802.3 specifications.
shows the definition of the IDLE ordered sets for
Ethernet XAUI.
Table 11.3. XAUI IDLE Ordered Sets Definition
Code
Ordered Sets
Number of Code
Encoding
ǁAǁ
Sync Column
4
/28.5//28.5//28.5//28.5/
ǁKǁ
Skip Column
4
/28.0//28.0//28.0//28.0/
ǁRǁ
Align Column
4
/28.3//28.3//28.3//28.3/
The XAUI receiver need be AC-coupled to the XAUI, and a 100 nF AC-coupling capacitor is recommended to be used in
an AC-coupled link.
SGMII Mode and QSGMII Mode
The Serial Gigabit Media Independent Interface (SGMII) designed by Cisco is to convey network data, and port speed
between a 10/100/1000 PHY and a MAC with significantly fewer signal pins than required for GMII. The SGMII interface
can operate in both half and full duplex and at all ports speeds. The Quad Serial Gigabit Media Independent Interface
(QSGMII) is designed to convey four ports of network data between Ethernet PHY and MAC like SGMII.
The SGMII mode and QSGMII mode of CertusPro-NX SerDes/PCS fully supports from serial I/O to GMII interface. In
SGMII mode, SerDes/PCS block is configured as single lane at 1.25Gbps, based on 8B/10B PCS. In QSGMII mode,
SerDes/PCS block is configured as single lane at 5Gbps, based on 8B/10B PCS.
SGMII and QSGMII supports both AC and DC coupled operation. CertusPro-NX SerDes/PCS supports both AC-coupling
and DC-coupling link. A 100nF AC-coupling capacitor is recommended to be used in an AC coupled link.
10GBASE-R Mode
The 10GBASE-R mode of CertusPro-NX SerDes/PCS is intended for the connection between XGMII and 10 Gigabit serial
I/O, in 10 Gigabit Ethernet applications specified by IEEE802.3. In 10GBASE-R mode, CertusPro-NX SerDes/PCS is
configured as single lane at 10.3125Gbps, based on 64B/66B PCS.
The 64B/66B PCS encodes eight data octets or control characters, and 2-bit synchronization header into a block. Blocks
containing control characters also contain a block type field. Data octets are labeled from D
0
to D
7
. Control characters
other than ordered sets (/O/), start control character (/S/) and termination control character (/T/) are labeled from C
0
to C
7
. The control character for ordered sets are labeled as O
0
or O
4
, as it is only valid on the first octet of the XGMII.
The control character for start is labeled as S
0
or S
4
for the same reason. The control character for terminate is labeled
from T
0
to T
7
.