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.