F-Tile Ethernet Intel® FPGA Hard IP User Guide

ID 683023
Date 3/28/2022
Public

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4.2.1.4. Frame Padding

When the length of client frame is less than 64 bytes and greater than eight bytes, the TX MAC module inserts pad bytes after the payload to create a frame length equal to the minimum size of 64 bytes. If the i_tx_skip_crc or i_tx_mac_skip_crc signal is asserted while writing frame data, the core does not insert PAD bytes even if the frame is shorter than 64 bytes long.

CAUTION:
When using the MAC segmented interface, if the Enable preamble passthrough parameter and the i_tx_mac_skip_crc signal are both disabled, the payload length must not be less than 9 bytes. However, if the Enable preamble passthrough parameter and the i_tx_mac_skip_crc signal are both enabled, the entire frame, including Preamble and CRC, must not be less than 9 bytes. You must ensure that such frames do not reach the TX client interface as the F-Tile Ethernet Intel FPGA Hard IP discards them.