Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP User Guide

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ID 683221
Date 11/10/2022
Public
Document Table of Contents
Document Table of Contents x
1. About the Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP 2. Low Latency 40G for ASIC Proto 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. Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP User Guide Archives 11. Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP Revision History
1. About the Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP x
1.1. Low Latency 40G for ASIC Proto Ethernet IP Core Supported Features 1.2. Device Family Support 1.3. Low Latency 40G for ASIC Proto Ethernet IP Core Device Speed Grade Support 1.4. Resource Utilization 1.5. Release Information
3. Getting Started x
3.1. Installing and Licensing Intel® FPGA IP Cores 3.2. Specifying the Low Latency 40G for ASIC Proto Ethernet 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. Low Latency 40G for ASIC Proto 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. Adding the External TX MAC PLL 3.5.4. Placement Settings for the Low Latency 40G for ASIC Proto Ethernet Core
3.6. Low Latency 40G for ASIC Proto Ethernet IP Core Testbench x
3.6.1. Understanding the Testbench Behavior
4. Functional Description x
4.1. Low Latency 40G for ASIC Proto Ethernet Core Functional Description 4.2. User Interface to Ethernet Transmission
4.1. Low Latency 40G for ASIC Proto Ethernet Core Functional Description x
4.1.1. Low Latency 40G for ASIC Proto Ethernet Core TX MAC Datapath 4.1.2. Low Latency 40G for ASIC Proto Ethernet Core RX MAC Datapath 4.1.3. Link Fault Signaling Interface 4.1.4. Flow Control
4.1.1. Low Latency 40G for ASIC Proto Ethernet 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
4.1.2. Low Latency 40G for ASIC Proto Ethernet 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
4.1.4. Flow Control x
4.1.4.1. TX Pause/PFC Flow Control Transmission 4.1.4.2. XON/XOFF Pause Frames
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. TX PCS Interface to User Logic 6.4. RX PCS Interface to User Logic 6.5. Transceivers Signals 6.6. Transceiver Reconfiguration Signals 6.7. Avalon® Memory-Mapped Management Interface 6.8. Miscellaneous Status and Debug Signals 6.9. Reset Signals 6.10. Clocks 6.11. Flow Control Interface
7. Control, Status, and Statistics Register Descriptions x
7.1. PHY Registers 7.2. TX MAC Registers 7.3. RX MAC Registers 7.4. Statistics Registers
7.4. Statistics Registers x
7.4.1. TX Statistics Registers 7.4.2. RX Statistics Registers
9. Ethernet Toolkit Overview x
9.1. Features
1. About the Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP
2. Low Latency 40G for ASIC Proto 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. Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP User Guide Archives
11. Low Latency 40G for ASIC Proto Ethernet Intel® FPGA IP Revision History

4.1.2.3.1. Length Checking

The MAC function checks the frame and payload lengths of basic, VLAN tagged, and stacked VLAN tagged frames.

The IP core checks that the frame length is valid—is neither undersized nor oversized. A valid frame length is at least 64 (0x40) bytes and does not exceed the following maximum value for the different frame types:

  • Basic frames—The number of bytes specified in the MAX_RX_SIZE_CONFIG register.
  • VLAN tagged frames—The value specified in the MAX_RX_SIZE_CONFIG register plus four bytes.
  • Stacked VLAN tagged frames—The value specified in the MAX_RX_SIZE_CONFIG register plus eight bytes.

If the length/type field in a basic MAC frame or the client length/type field in a VLAN tagged frame has a value less than 0x600, the IP core also checks the payload length. The IP core keeps track of the payload length as it receives a frame, and checks the length against the relevant frame field. The payload length is valid if it satisfies the following conditions:

The RX MAC does not drop frames with invalid length or invalid payload length. If the frame or payload length is not valid, the MAC function asserts output error bits.

If the length field value is greater than the actual payload length, the IP core asserts . If the length field value is less than the actual payload length, the MAC RX considers the frame to have excessive padding and does not assert .

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