Low Latency 40G Ethernet Intel® FPGA IP User Guide: Agilex™ 5 FPGAs and SoCs

ID 813652
Date 7/22/2024
Public
Document Table of Contents

4.3.1. Preamble Pass-through/Insertion

If preamble pass-through mode is selected, the IP transmits the preamble and Ethernet frame that comes in on the user interface. You can only control the last 7 bytes of the preamble.

If the preamble insertion mode is selected, the IP inserts the standard Ethernet preamble into the received Ethernet frames and send it out.

In preamble pass through mode, l2_tx_startofpacket and l2_rx_startofpacket are asserted at the preamble bytes.

In non-preamble pass through mode, l2_tx_startofpacket and l2_rx_startofpacket are asserted at the first byte of destination address of the frame.