The Lattice 2.5 Gbps Ethernet PCS IP core implements the state machine functions for the physical coding sublayer (PCS) described in the IEEE 802.3z (1000BaseX) specification. Note that the IEEE specification describes a PCS that operates at 1Gbps. Therefore, this 2.5G PCS IP core is non-standard with respect to the IEEE specification.
The two major non-compliances are data rate (2.5 Gbps instead of 1 Gbps) and GMII data bus width (16 bits instead of 8 bits).
This PCS IP core was specifically developed to operate with the Lattice 2.5 Gbps MAC IP core. The Lattice 2.5G PCS and MAC IP cores are 100% compatible and can be used to create a full PHY/MAC Ethernet data path that operates at 2.5 Gbps.
This document describes the 2.5 Gbps Ethernet PCS IP core’s operation, and provides instructions for generating the core through the Lattice IPexpress™ tool, and for instantiating, synthesizing, and simulating the core.
The 2.5 Gbps Ethernet PCS IP core converts GMII frames into 8-bit code groups in both transmit and receive directions and performs auto-negotiation with a link partner as described in IEEE 802.3z specification.