The transmit FLEX I/F can only be used when the DCMAC Subsystem is configured in Independent MAC and PCS+FEC mode. This mode is selected using the ctl_tx_independent_tsmac_and_phy_mode control field of the GLOBAL_MODE register. This field is configured statically when there is no data flowing through the DCMAC Subsystem.
| c<N>_ctl_tx_flexif_select[1:0] | Operating Mode | Application Description |
|---|---|---|
| 2'b00 | For PHYs that include FEC, provides direct access to the FEC sublayer
where (through separate controls) transcoding can be bypassed. This
mode disables the PCS scrambler function and the AM insertion
function. This mode should also be set for modes using FEC transcoder bypass. |
Transparent mapping of 100GE into OTN |
| 2'b01 | This mode enables the PCS scrambler function and the AM insertion function. | Flex Ethernet PHY with no EBLOCK replacement |
| 2'b10 | Reserved. | Reserved |
| 2'b11 | This mode enables the PCS scrambler function, the AM insertion function, the 66-bit sync header error replacement by EBLOCK, and enables the PCS transmit state machine. | PCS mode with legalized 66-bit block stream |