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1. About Triple-Speed Ethernet Intel® FPGA IP for Agilex™ 5 devices
2. Getting Started
3. Parameter Settings
4. Functional Description
5. Configuration Register Space
6. Interface Signals
7. Design Considerations
8. Timing Constraints
9. Testbench
10. Triple-Speed Ethernet Intel® FPGA IP User Guide Archives
11. Document Revision History for the Triple-Speed Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs
A. Ethernet Frame Format
B. Simulation Parameters
4.1.1. MAC Architecture
4.1.2. MAC Interfaces
4.1.3. MAC Transmit Datapath
4.1.4. MAC Receive Datapath
4.1.5. MAC Transmit and Receive Latencies
4.1.6. FIFO Buffer Thresholds
4.1.7. Congestion and Flow Control
4.1.8. Magic Packets
4.1.9. MAC Local Loopback
4.1.10. MAC Reset
4.1.11. PHY Management (MDIO)
4.1.12. Connecting MAC to External PHYs
6.1.1. 10/100/1000 Ethernet MAC Signals
6.1.2. 10/100/1000 Multiport Ethernet MAC Signals
6.1.3. 10/100/1000 Ethernet MAC with 1000BASE-X/SGMII PCS Signals
6.1.4. 10/100/1000 Ethernet MAC with Internal FIFO Buffers, and 1000BASE-X/SGMII 2XTBI PCS with Embedded PMA (GTS) Signals
6.1.5. 10/100/1000 Multiport Ethernet MAC with 1000BASE-X/SGMII PCS Signals
6.1.6. 1000BASE-X/SGMII PCS Signals
6.1.7. 1000BASE-X/SGMII 2XTBI PCS Signals
6.1.1.1. Clock and Reset Signals
6.1.1.2. Clock Enabler Signals
6.1.1.3. MAC Control Interface Signals
6.1.1.4. MAC Status Signals
6.1.1.5. MAC Receive Interface Signals
6.1.1.6. MAC Transmit Interface Signals
6.1.1.7. Pause and Magic Packet Signals
6.1.1.8. MII/GMII/RGMII Signals
6.1.1.9. PHY Management Signals
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4.1.6.3. Transmit FIFO Buffer Underflow
If the transmit FIFO buffer hits the almost-empty threshold during transmission and the FIFO buffer does not contain the end-of-packet indication, the MAC function stops reading data from the FIFO buffer and initiates the following actions:
- The MAC function asserts the RGMII/GMII/MII error signals (tx_control/gm_tx_err/m_tx_err) to indicate that the fragment transferred is not valid.
- The MAC function deasserts the RGMII/GMII/MII transmit enable signals (tx_control/gm_tx_en/m_tx_en) to terminate the frame transmission.
- After the underflow, the user application completes the frame transmission.
- The transmitter control discards any new data in the FIFO buffer until the end of frame is reached.
- The MAC function starts to transfer data on the RGMII/GMII/MII when the user application sends a new frame with an SOP.
Figure 17. Transmit FIFO Buffer UnderflowFigure illustrates the FIFO buffer underflow protection algorithm for gigabit Ethernet system.