Low Latency 40-Gbps Ethernet IP Core User Guide

ID 683745
Date 3/08/2021
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1.1. LL 40GbE IP Core Supported Features

All LL 40GbE IP core variations include both a MAC and a PHY, and all variations are in full-duplex mode. These IP core variations offer the following features:

  • Designed to the IEEE 802.3ba-2010 High Speed Ethernet Standard available on the IEEE website (www.ieee.org).
  • Soft PCS logic that interfaces seamlessly to Intel FPGA 10.3125 Gbps serial transceivers.
  • Standard XLAUI external interface consisting of four FPGA hard serial transceiver lanes operating at 10.3125 Gbps.
  • Supports 40GBASE-KR4 PHY based on 64B/66B encoding with data striping and alignment markers to align data from multiple lanes.
  • Supports 40GBASE-KR4 PHY and forward error correction (FEC) option for interfacing to backplanes. The supported FEC is KR-FEC.
  • Supports Synchronous Ethernet (SyncE) by providing an optional CDR recovered clock output signal to the device fabric.
  • Avalon® memory mapped (Avalon-MM) management interface to access the IP core control and status registers.
  • Avalon® streaming (Avalon-ST) data path interface connects to client logic with the start of frame in the most significant byte (MSB) when optional adapters are used. Interface has data width 256 bits.
  • Optional custom streaming data path interface with narrower bus width and a start frame possible on 64‑bit word boundaries without the optional adapters. Interface has data width 128 bits.
  • Support for jumbo packets.
  • TX and RX CRC pass-through control.
  • Optional TX CRC generation and insertion.
  • RX CRC checking and error reporting.
  • TX error insertion capability supports test and debug.
  • RX and TX preamble pass-through options for applications that require proprietary user management information transfer.
  • TX automatic frame padding to meet the 64-byte minimum Ethernet frame length at the LL 40GbE Ethernet connection.
  • Optional RX strict SFD checking per IEEE specification.
  • RX malformed packet checking per IEEE specification.
  • Hardware and software reset control.
  • Pause frame filtering control.
  • Received control frame type indication.
  • MAC provides cut-through frame processing.
  • Optional deficit idle counter (DIC) options to maintain a finely controlled 8-byte or 12-byte inter-packet gap (IPG) minimum average.
  • Optional IEEE 802.3 Clause 31 Ethernet flow control operation using the pause registers or pause interface.
  • Optional priority-based flow control that complies with the IEEE Standard 802.1Qbb-2011—Amendment 17: Priority-based Flow Control, using the pause registers for fine control.
  • 1900 bits RX PCS lane skew tolerance, which exceeds the IEEE 802.3-2012 Ethernet standard clause 82.2.12 requirements.
  • Optional support for the IEEE Standard 1588-2008 Precision Clock Synchronization Protocol (1588 PTP).
  • Optional statistics counters.
  • Optional fault signaling: detects and reports local fault and generates remote fault, with IEEE 802.3ba-2012 Ethernet Standard Clause 66 support.
  • Optional serial PMA loopback (TX to RX) at the serial transceiver for self-diagnostic testing.
  • Optional access to Native PHY Debug Master Endpoint (NPDME) for debugging or monitoring PHY signal integrity.

The LL 40GbE IP core can support full wire line speed with a 64-byte frame length and back-to-back or mixed length traffic with no dropped packets.

For a detailed specification of the Ethernet protocol refer to the IEEE 802.3ba-2010 High Speed Ethernet Standard.