F-Tile Ethernet Intel® FPGA Hard IP User Guide

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ID 683023
Date 10/04/2021
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Document Table of Contents
Document Table of Contents x
1. Overview 2. Getting Started 3. F-Tile Ethernet Intel® FPGA Hard IP Parameters 4. Functional Description 5. Clocks 6. Resets 7. Interface Overview 8. Configuration Registers 9. Supported Modules and IPs 10. Supported Tools 11. F-Tile Ethernet Intel® FPGA Hard IP User Guide Archives 12. Document Revision History
1. Overview x
1.1. Ethernet System in F-Tile Overview 1.2. F-Tile Ethernet Intel® FPGA Hard IP Overview
1.2. F-Tile Ethernet Intel® FPGA Hard IP Overview x
1.2.1. Device Family Support 1.2.2. Resource Utilization 1.2.3. Release Information
2. Getting Started x
2.1. Installing and Licensing F-Tile Ethernet Intel® FPGA Hard IP Cores 2.2. Specifying the IP Core Parameters and Options 2.3. Reference and System PLL Clock for your IP Design 2.4. Generated File Structure 2.5. Generating Tile Files 2.6. IP Core Testbenches
4. Functional Description x
4.1. Datapath Description 4.2. F-Tile Ethernet Intel® FPGA Hard IP MAC 4.3. PCS, OTN, and FlexE Modes 4.4. Precision Time Protocol 4.5. Auto-Negotiation and Link Training
4.2. F-Tile Ethernet Intel® FPGA Hard IP MAC x
4.2.1. MAC TX Datapath 4.2.2. MAC RX Datapath 4.2.3. Congestion and Flow Control Using PAUSE or Priority Flow Control (PFC) 4.2.4. Link Fault Signaling 4.2.5. Order of Ethernet Transmission
4.2.1. MAC TX Datapath x
4.2.1.1. TX Preamble, Start, and SFD Insertion 4.2.1.2. Source Address Insertion 4.2.1.3. Length/Type Field Processing 4.2.1.4. Frame Padding 4.2.1.5. Frame Check Sequence (CRC-32) Insertion 4.2.1.6. Inter-Packet Gap Generation and Insertion
4.2.2. MAC RX Datapath x
4.2.2.1. RX Preamble Processing 4.2.2.2. RX Strict SFD Checking 4.2.2.3. RX FCS Checking 4.2.2.4. RX Malformed Packet Handling 4.2.2.5. Removing PAD Bytes and FCS Bytes from RX Frames 4.2.2.6. RX Undersized Frames, Oversized Frames, and Frames with Length Errors 4.2.2.7. Inter-Packet Gap
4.2.3. Congestion and Flow Control Using PAUSE or Priority Flow Control (PFC) x
4.2.3.1. Conditions Triggering XOFF Frame Transmission 4.2.3.2. Conditions Triggering XON Frame Transmission 4.2.3.3. Pause Control and Generation Interface 4.2.3.4. Pause Control Frame Filtering
4.3. PCS, OTN, and FlexE Modes x
4.3.1. PCS Mode 4.3.2. OTN Mode 4.3.3. FlexE Mode
4.4. Precision Time Protocol x
4.4.1. Features 4.4.2. PTP Timestamp Accuracy 4.4.3. PTP Client Flow 4.4.4. RX Virtual Lane Offset Calculation for No FEC Variants 4.4.5. Virtual Lane Order and Offset Values 4.4.6. UI Adjustment 4.4.7. Reference Time Interval 4.4.8. Minimum and Maximum Reference Time (TAM) Interval for UI Measurement (Hardware) 4.4.9. UI Value and PMA Delay 4.4.10. Routing Delay Adjustment for Advanced Timestamp Accuracy Mode
4.4.3. PTP Client Flow x
4.4.3.1. PTP TX Client Flow 4.4.3.2. PTP RX Client Flow
4.4.6. UI Adjustment x
4.4.6.1. TX UI Adjustment 4.4.6.2. RX UI Adjustment
5. Clocks x
5.1. Clock Connections in Single Instance Operation 5.2. Clock Connections in Multiple Instance Operation 5.3. Clock Connections in MAC Asynchronous FIFO Operation 5.4. Clock Connections in PTP-Based Synchronous and Asynchronous Operation 5.5. Clock Connections in Synchronous Ethernet Operation 5.6. Custom Cadence
6. Resets x
6.1. Reset Signals 6.2. Reset Sequence
7. Interface Overview x
7.1. Status Interface 7.2. TX MAC Avalon ST Client Interface 7.3. RX MAC Avalon ST Aligned Client Interface 7.4. TX MAC Segmented Client Interface 7.5. RX MAC Segmented Client Interface 7.6. MAC Flow Control Interface 7.7. PCS Mode TX Interface 7.8. PCS Mode RX Interface 7.9. FlexE and OTN Mode TX Interface 7.10. FlexE and OTN Mode RX Interface 7.11. Custom Rate Interface 7.12. Reconfiguration Interfaces 7.13. Precision Time Protocol Interface
7.2. TX MAC Avalon ST Client Interface x
7.2.1. TX MAC Avalon ST Client Interface with Disabled Preamble Passthrough 7.2.2. TX MAC Avalon ST Client Interface with Enabled Preamble Passthrough 7.2.3. Using MAC Avalon ST skip_crc Signal to Control Source Address, PAD, and CRC Insertion 7.2.4. Using MAC Avalon ST i_tx_error Signal to Mark Packets Invalid
7.3. RX MAC Avalon ST Aligned Client Interface x
7.3.1. RX MAC Avalon ST Client Interface with Disabled Preamble Passthrough 7.3.2. RX MAC Avalon ST Client Interface with Enabled Passthrough and RX CRC Forwarding 7.3.3. RX MAC Adapter Limitations 7.3.4. RX MAC Avalon ST Client Interface Status
7.4. TX MAC Segmented Client Interface x
7.4.1. TX MAC Segmented Client Interface with Disabled Preamble Passthrough 7.4.2. TX MAC Segmented Client Interface with Enabled Preamble Passthrough 7.4.3. Using MAC Segmented skip_crc Signal to Control Source Address, PAD, and CRC Insertion 7.4.4. Using MAC Segmented i_tx_mac_error to Mark Packets Invalid
7.5. RX MAC Segmented Client Interface x
7.5.1. RX MAC Segmented Client Interface with Disabled Preamble Passthrough 7.5.2. RX MAC Segmented Client Interface with Enabled Passthrough and RX CRC Forwarding 7.5.3. RX MAC Segmented Client Interface Status and Errors
7.12. Reconfiguration Interfaces x
7.12.1. Ethernet Reconfiguration Interfaces 7.12.2. Transceiver Reconfiguration Interfaces
7.13. Precision Time Protocol Interface x
7.13.1. Time-of-Day Interface 7.13.2. TX 2-Step Timestamp Interface 7.13.3. TX 1-Step Timestamp Interface 7.13.4. RX Timestamp Interface 7.13.5. PTP Status Interface 7.13.6. PTP Tile Interface
7.13.3. TX 1-Step Timestamp Interface x
7.13.3.1. PTP Field Offset for 1-Step Operation
8. Configuration Registers x
8.1. Ethernet Avalon® Memory-Mapped Interface Address Space 8.2. Transceiver Avalon® Memory-Mapped Interface Address Space
8.1. Ethernet Avalon® Memory-Mapped Interface Address Space x
8.1.1. Ethernet Hard IP Core CSRs 8.1.2. FEC and Transceiver Control and Status Registers
9. Supported Modules and IPs x
9.1. F-Tile Auto-Negotiation and Link Training For Ethernet Intel® FPGA IP 9.2. PTP Tile Adapter
9.1. F-Tile Auto-Negotiation and Link Training For Ethernet Intel® FPGA IP x
9.1.1. Overview 9.1.2. Release Information 9.1.3. Functional Description 9.1.4. Parameters 9.1.5. Clocks and Resets 9.1.6. Registers
9.2. PTP Tile Adapter x
9.2.1. Overview 9.2.2. Clocks, Reset, and Interface Ports 9.2.3. PTP Asymmetry Delay Reconfiguration Interface 9.2.4. PTP Peer-to-Peer MeanPathDelay Reconfiguration Interface
10. Supported Tools x
10.1. F-Tile Channel Placement Tool 10.2. Ethernet Toolkit Overview
10.2. Ethernet Toolkit Overview x
10.2.1. Features
1. Overview
2. Getting Started
3. F-Tile Ethernet Intel® FPGA Hard IP Parameters
4. Functional Description
5. Clocks
6. Resets
7. Interface Overview
8. Configuration Registers
9. Supported Modules and IPs
10. Supported Tools
11. F-Tile Ethernet Intel® FPGA Hard IP User Guide Archives
12. Document Revision History

4.2.1.6. Inter-Packet Gap Generation and Insertion

If you set Average Inter-packet Gap to 12 in the F-Tile Ethernet Intel® FPGA Hard IP parameter editor, the TX MAC maintains the minimum inter-packet gap (IPG) between transmitted frames required by the IEEE 802.3 Ethernet standard. The standard requires an average minimum IPG of 96 bit times (or 12 byte times). The MAC uses a deficit idle counter to allow the actual gap between frames to vary as needed to meet the maximum throughput requirements of the link.

If you set Average Inter-packet Gap to 10 or 8, the TX MAC maintains a minimum average IPG of 10 or 8 bytes accordingly. This option is provided as an intermediate option to allow you to enforce an IPG that does not conform to the Ethernet standard, but which increases the throughput of your IP core.

If you set Average Inter-packet Gap to 1, the IP core transmits Ethernet packets as soon as the data is available, with the minimum possible gap. The IPG depends on the space you leave between frame data as you write it to the core. If you select this parameter value, the core no longer complies with the Ethernet standard, but your application has control over the average gap and throughput can be maximized. For a packet of size (P) bytes, the number of idles bytes (G) inserted after is specified by the following formula G=8-(P%8). A few examples are depicted below:
Packet Size (P) Gap Idle Bytes (G)
64 8
65 7
66 6
67 5
68 4
69 3
70 2
71 1
72 8
Note: Even when you set the Average Inter-packet Gap to 1, the 10GE/25GE channels still enforces an effective IPG of 5. This is because the protocol specifically prohibits IPG lower than 5 for 10GE/25GE links to prevent MACs from producing packets that cannot be encoded using 64B/66B encoders.
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