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

ID 813652
Date 11/25/2024
Public
Document Table of Contents

4.3.1.1. Preamble Insertion

If Enable 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 Enable preamble pass-through mode is not 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.