Low Latency 40-Gbps Ethernet Intel® FPGA IP User Guide: Stratix® 10

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ID 683600
Date 5/31/2024
Public
Document Table of Contents
Document Table of Contents x
1. About the Low Latency 40G Ethernet Core 2. Stratix® 10 Low Latency 40G Ethernet IP Core Parameters 3. Getting Started 4. Functional Description 5. Reset 6. Interfaces and Signal Descriptions 7. Control, Status, and Statistics Register Descriptions 8. Debugging the Link 9. Ethernet Toolkit Overview 10. Stratix® 10 Low Latency 40GbE IP Core User Guide Archives 11. Differences Between Stratix® 10 Low Latency 40G Ethernet IP Core and Low Latency 40G Ethernet IP Core That Targets an Arria 10 Device 12. Document Revision History for Stratix® 10 Low Latency 40G Ethernet User Guide
1. About the Low Latency 40G Ethernet Core x
1.1. Stratix® 10 LL 40GbE IP Core Supported Features 1.2. Stratix® 10 LL 40GbE Core Device Family and Speed Grade Support 1.3. Resource Utilization 1.4. Release Information
1.2. Stratix® 10 LL 40GbE Core Device Family and Speed Grade Support x
1.2.1. Device Family Support 1.2.2. Stratix® 10 LL 40GbE IP Core Device Speed Grade Support
3. Getting Started x
3.1. Installing and Licensing Intel® FPGA IP Cores 3.2. Specifying the Stratix® 10 LL 40GbE IP Core Parameters and Options 3.3. Simulating the IP Core 3.4. Generated File Structure 3.5. Integrating Your IP Core in Your Design 3.6. Stratix® 10 Low Latency 40G Ethernet IP Core Testbench 3.7. Compiling the Full Design and Programming the FPGA
3.5. Integrating Your IP Core in Your Design x
3.5.1. Pin Assignments 3.5.2. Adding the Transceiver PLL 3.5.3. Clock Requirements for 40GBASE-KR4/CR4 Variations 3.5.4. Adding the External TX MAC PLL 3.5.5. Placement Settings for the Stratix® 10 Low Latency 40G Ethernet Core
3.6. Stratix® 10 Low Latency 40G Ethernet IP Core Testbench x
3.6.1. Understanding the Testbench Behavior
4. Functional Description x
4.1. Stratix® 10 LL 40GbE Core Functional Description 4.2. User Interface to Ethernet Transmission
4.1. Stratix® 10 LL 40GbE Core Functional Description x
4.1.1. Stratix® 10 LL 40GbE Core TX MAC Datapath 4.1.2. Stratix® 10 LL 40GbE Core RX MAC Datapath 4.1.3. Link Fault Signaling Interface 4.1.4. Stratix® 10 Low Latency 40GBASE-KR4 IP Core Variations
4.1.1. Stratix® 10 LL 40GbE Core TX MAC Datapath x
4.1.1.1. Frame Padding 4.1.1.2. Preamble Insertion 4.1.1.3. Inter-Packet Gap Generation and Insertion 4.1.1.4. Frame Check Sequence (CRC-32) Insertion
4.1.2. Stratix® 10 LL 40GbE Core RX MAC Datapath x
4.1.2.1. IP Core Preamble Processing 4.1.2.2. IP Core Strict SFD Checking 4.1.2.3. Length/Type Field Processing 4.1.2.4. RX CRC Checking and Dynamic Forwarding
4.1.2.3. Length/Type Field Processing x
4.1.2.3.1. Length Checking
4.2. User Interface to Ethernet Transmission x
4.2.1. Order of Transmission 4.2.2. Bit Order For TX and RX Datapaths
6. Interfaces and Signal Descriptions x
6.1. TX MAC Interface to User Logic 6.2. RX MAC Interface to User Logic 6.3. Transceivers Signals 6.4. Transceiver Reconfiguration Signals 6.5. Avalon® Memory-Mapped Management Interface 6.6. Miscellaneous Status and Debug Signals 6.7. Reset Signals 6.8. Clocks 6.9. Flow Control Interface
7. Control, Status, and Statistics Register Descriptions x
7.1. Stratix® 10 LL 40GBASE-KR4/CR4 Registers 7.2. PHY Registers 7.3. TX MAC Registers 7.4. RX MAC Registers 7.5. Statistics Registers
7.5. Statistics Registers x
7.5.1. TX Statistics Registers 7.5.2. RX Statistics Registers
9. Ethernet Toolkit Overview x
9.1. Features
1. About the Low Latency 40G Ethernet Core
2. Stratix® 10 Low Latency 40G Ethernet IP Core Parameters
3. Getting Started
4. Functional Description
5. Reset
6. Interfaces and Signal Descriptions
7. Control, Status, and Statistics Register Descriptions
8. Debugging the Link
9. Ethernet Toolkit Overview
10. Stratix® 10 Low Latency 40GbE IP Core User Guide Archives
11. Differences Between Stratix® 10 Low Latency 40G Ethernet IP Core and Low Latency 40G Ethernet IP Core That Targets an Arria 10 Device
12. Document Revision History for Stratix® 10 Low Latency 40G Ethernet User Guide

6.2. RX MAC Interface to User Logic

The RX MAC provides an Avalon® streaming interface to the FPGA fabric. The datapath comprises 2, 64-bit words.
Table 14.   Avalon® Streaming RX MAC Interface Signals All interface signals are clocked by the clk_rxmac clock.

Signal

Direction

Description

clk_rxmac Output Clock for the RX MAC. Recovered from the incoming data. This clock is guaranteed stable when rx_pcs_ready is asserted. The frequency of this clock is 312.5 MHz. All RX MAC interface signals are synchronous to clk_rxmac.
l2_rx_data[127:0] Output

Data output from the MAC. Bit 127 is the MSB and bit 0 is the LSB. Bytes are read in the usual left to right order. The IP core reverses the byte order to meet the requirements of the Ethernet standard.

l2_rx_preamble[63:0] Output

Received preamble data. Available when you select PREAMBLE PASS-THROUGH mode.

Valid when l2_rx_startofpacket is asserted.
l2_rx_valid Output When asserted, indicates that l2_rx_data[127:0] is driving data.
l2_rx_startofpacket Output

When asserted, indicates the first byte of a frame.

l2_rx_endofpacket Output When asserted, indicates the last data byte of a frame, before the frame check sequence (FCS). In CRC pass-through mode, it is the last byte of the FCS. The packet can end at any byte position.
l2_rx_empty[3:0] Output Specifies the number of empty bytes when l2_rx_endofpacket is asserted.

The packet can end at any byte position. The empty bytes are the low-order bytes.

l2_rx_error[5:0] Output

When asserted in the same cycle as l2_rx_endofpacket, indicates the current packet should be treated as an error packet. The 6 bits of l<n>_rx_error specify the following errors:

  • l2_rx_error[5]: Unused.
  • l2_rx_error[4]: Payload length error. The length field has a value less than 1535 (0x600) bytes and the received payload length is less than what is advertised in the length field.
  • l2_rx_error[3]: Oversized frame. The frame size is greater than the value specified in the MAX_RX_SIZE_CONFIG register.
  • l2_rx_error[2]: Undersized frame – The frame size is less than 64 bytes. Frame size = header size + payload size.
  • l2_rx_error[1]: CRC Error. The computed CRC value differs from the received CRC.
  • l2_rx_error[0]: Malformed packet. The packet is terminated with a non-terminate control character. When this bit is asserted, l2_rx_error[1] is also asserted.
l2_rxstatus_valid Output When asserted, indicates that l2_rxstatus_data is driving valid data.
l2_rxstatus_data[39:0] Output

Specifies information about the received frame. The following fields are defined:

  • [Bit 39]: When asserted, indicates a PFC frame
  • [Bit 38]: When asserted, indicates a unicast frame
  • Bit[37]: When asserted, indicates a multicast frame
  • Bit[36]: When asserted, indicates a broadcast frame
  • Bit[35]: When asserted, indicates a pause frame
  • Bit[34]: When asserted, indicates a control frame
  • Bit[33]: When asserted, indicates a VLAN frame
  • Bit[32]: When asserted, indicates a stacked VLAN frame
  • Bits[31:16]: Specifies the frame length from the first byte of the destination address to the last bye of the FCS
  • Bits[15:0]: Specifies the payload length
Figure 14. MAC to Client Avalon® Streaming Interface l2_rx_data reception order is highest byte to lowest byte. The first byte of the destination address is on l2_rx_data[127:120] , 0xabe42339 . . . in this timing diagram.
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