E-tile Hard IP User Guide: E-Tile Hard IP for Ethernet and E-Tile CPRI PHY Intel® FPGA IPs

ID 683468
Date 12/28/2022

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Document Table of Contents RX Preamble Processing

The preamble sequence is Start, six preamble bytes, and SFD. The Start byte must be on receive lane 0 of the MII, which means byte [7:0] of the data decoded from a 66b block. The IP core uses the Start Control byte (0xFB, with the corresponding MII control bit set to 1) to identify the start of the Ethernet packet, and the location of the preamble.

By default, the MAC RX removes all Start, SFD, preamble, and IPG bytes from accepted frames. However, if you turn on Enable preamble passthrough in the E-Tile Hard IP for Ethernet Intel FPGA IP parameter editor, the MAC RX does not remove the eight-byte preamble sequence.