40- and 100-Gbps Ethernet MAC and PHY MegaCore Function User Guide

ID 683114
Date 6/15/2022
Public
Document Table of Contents

3.2.3.3. 40-100GbE IP Core FCS (CRC-32) Removal

Independent user configuration register bits control FCS CRC removal at runtime. CRC removal supports both narrow and wide bus options. Bit 1 of the CRC_CONFIG register enables and disables CRC removal; by default, CRC removal is enabled.

In the user interface, the EOP signal (l<n>_rx_endofpacket or dout_last_data ) indicates the end of CRC bytes if CRC is not removed. When CRC is removed, the EOP signal indicates the final byte of payload.

By default, the IP core asserts the FCS error signal (l<n>_rx_fcs_error or dout_fcs_error) and the EOP signal on the same clock cycle if the current frame has an FCS error. However, if the IP core is in RX automatic pad removal mode, the signals might not be asserted in the same clock cycle.