Port FEC Mode - 2.3 English

Versal Devices Integrated 100G Multirate Ethernet MAC Subsystem Product Guide (PG314)

Document ID
PG314
Release Date
2024-05-30
Version
2.3 English

Forward error correction (FEC) is available on the PHYs of the MRMAC port. FEC can be enabled or disabled on a per-port basis.

The FEC_CONFIGURATION_REG needs to be configured appropriately for the FEC to work. For example, the Clause 49 flag should be set to 1 for modes which require Clause 49 transcoding (25GE, 50GE, Fibre Channel) and set to 0 for modes which require Clause 82 transcoding (100GE). CTL_TX_FEC_FOUR_LANE_PMD needs to set to 1 for 100CAUI-4 with RSFEC (it should be set to 0 100GAUI-2 and other modes). For additional details, refer to the Register description sheet of MRMAC Register document.

The various FEC operating modes are selected through the ctl_fec_mode field of the FEC_CONFIGURATION_REG configuration register. A change in the FEC_CONFIGURATION_REG of the port requires a reset being driven to that port after configuration is complete.

For a 50G configuration, the alignment marker spacing changes depending on whether RSFEC is enabled. The 50G alignment marker spacing should be set to 0x3FFF when RSFEC is disabled and 0x4FFF when RSFEC is enabled, via ctl_tx_vl_length_minus1_50ge_0/2 and ctl_rx_vl_length_minus1_50ge_0/2.

Table 1. FEC Operating Modes
MRMAC Port Operating Rate ctl_fec_mode_<N>[3:0] Description
0 All rates 'b0000 FEC Disabled
100GE 'b1000 IEEE 802.3 RS(528,514) FEC
'b1010 IEEE P802.3cd/D3.5 CL91 RS(544,514) FEC
'b1011 ITU-T FlexEO RS(544,514) FEC
50GE 'b0100 25G/50G Ethernet Consortium RS(528,517) FEC
'b0101 IEEE P802.3cd/D3.5 CL134 RS(544,514) FEC
'b1111 IEEE 802.3 CL74 FEC
40GE 'b1101 IEEE 802.3 CL74 FEC
25GE 'b0010 25G/50G Ethernet Consortium RS(528,514) FEC
'b0011 IEEE 802.3 CL108 RS(528,514) FEC
'b1110 IEEE 802.3 CL74 FEC
10GE 'b1100 IEEE 802.3 CL74 FEC
32GFEC 'b0001 32GFEC (Valid only for Flex Interface)
1 All rates 'b0000 FEC Disabled
25GE 'b0010 25G/50G Ethernet Consortium RS(528,514) FEC
'b0011 IEEE 802.3 CL108 RS(528,514) FEC
'b1110 IEEE 802.3 CL74 FEC
10GE 'b1100 IEEE 802.3 CL74 FEC
32GFEC 'b0001 32GFEC (Valid only for Flex Interface)
2 All rates 'b0000 FEC Disabled
50GE 'b0100 25G/50G Ethernet Consortium RS(528,514) FEC
'b0101 IEEE P802.3cd/D3.5 CL134 RS(544,514) FEC
'b1111 IEEE CL74 25/50GE Ethernet Consortium
25GE 'b0010 25G/50G Ethernet Consortium RS(528,514) FEC
'b0011 IEEE 802.3 CL108 RS(528,514) FEC
'b1110 IEEE 802.3 CL74 FEC
10GE 'b1100 IEEE 802.3 CL74 FEC
32GFEC 'b0001 32GFEC (Valid only for Flex Interface)
3 All rates 'b0000 FEC Disabled
25GE 'b0010 25G/50G Ethernet Consortium RS(528,514) FEC
'b0011 IEEE 802.3 CL108 RS(528,514) FEC
'b1110 IEEE 802.3 CL74 FEC
10GE 'b1100 IEEE 802.3 CL74 FEC
32GFEC 'b0001 32GFEC (Valid only for Flex Interface)