The DCMAC Subsystem is statically configurable into one of two major modes of operation that govern the independence of logic within the subsystem.
Coupled MAC+PCS mode provides fully integrated MAC and PHY logic for up to six independent Ethernet ports totaling up to 600 Gbps of bandwidth. This mode is often called standard fixed Ethernet (FixedE) mode.
Independent MAC and PCS+FEC mode provides a standalone MAC supporting up to 600 Gbps bandwidth for up to 40 user-configurable channels. In this mode, the data flows between the AXI4-Stream interfaces and MAC interfaces (MAC I/F). Also, Independent MAC and PCS+FEC mode provides standalone PHY logic supporting up to 600 Gbps of bandwidth for up to 1 x 400 Gbps, 3 x 200 Gbps, 6 x 100 Gbps, or 12 x 50 Gbps interfaces. In this mode, data flows between the flex and transceiver interfaces.
The desired mode is selected using the control fields ctl_tx_independent_tsmac_and_phy_mode and ctl_rx_independent_tsmac_and_phy_mode of the GLOBAL_MODE register. These fields are configured statically when there is no data flowing through the DCMAC Subsystem.