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 Gb/s of bandwidth. This mode is often described as standard fixed Ethernet (FixedE) mode.
Independent MAC and PCS+FEC mode provides a standalone MAC supporting up to 600 Gb/s of bandwidth for up to 40 user-configurable channels. In this mode, data flows between the AXI4-Stream interfaces and MAC interfaces (MAC I/F). In addition, Independent MAC and PCS+FEC mode provides standalone PHY logic supporting up to 600 Gb/s of bandwidth for up to 1 x 400 Gb/s, 3 x 200 Gb/s, 6 x 100 Gb/s, or 12 x 50 Gb/s 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.