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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 for F-Tile Ethernet Intel® FPGA Hard IP User Guide
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
4.4.11. Routing Delay Adjustment for Basic Timestamp Accuracy Mode
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
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. Deterministic Latency Interface
7.13. 32-bit Soft CWBIN Counters
7.14. Reconfiguration Interfaces
7.15. Precision Time Protocol Interface
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
7.4.1. 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
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4.2.3.1. Conditions Triggering XOFF Frame Transmission
The F-Tile Ethernet Intel® FPGA Hard IP supports retransmission. In retransmission, the IP core retransmits a XOFF frame periodically, extending the pause time, based on signal values.
The TX MAC transmits PAUSE XOFF frames when one of the following conditions occurs:
- Client requests XOFF transmission—A client can explicitly request that XOFF frames be sent using the i_tx_pause and i_tx_pfc[7:0] signals. When i_tx_pause is asserted, a PAUSE XOFF frame is sent to the Ethernet network when the current frame transmission completes. When i_tx_pfc is asserted, a PFC XOFF packet is transmitted with XOFF requests for each of the Queues that has a bit high in the signal. For example, setting i_tx_pfc to 0x03 sends XOFF requests for Queues 0 and 1.
- Host (software) requests PAUSE XOFF transmission—Setting the pause request register triggers a request that a PAUSE XOFF frame be sent. Similarly, setting the PFC request register triggers PFC XOFF frame requests for the selected Priority Queues.
- Retransmission mode—If the retransmit hold-off enable bit has the value of 1, and the i_tx_pause signal remains asserted or the pause request register value remains high, when the time duration specified in the hold-off quanta register has lapsed after the previous PAUSE XOFF transmission, the TX MAC sends another PAUSE XOFF frame to the Ethernet network. The same mechanism applies to PFC. While the IP core is paused in retransmission mode, you cannot use either of the other two methods to trigger a new XOFF frame: the signal or register value is already high.
Note: Intel recommends that you use the flow control ports to backpressure the remote Ethernet node.