This Figure shows an example of the TX user interface signals in immediate NFC mode when an NFC message is received. The NFC message sends 8'b01 , requesting two cycles without data transmission. The core deasserts s_axi_tx_tready to prevent data transmission for two cycles.
Aurora 64B/66B cores can also operate in completion mode where NFC idles are only inserted before the first data bytes of a new frame. If a completion mode core receives an NFC message while it is transmitting a frame, the core finishes transmitting the frame before deasserting s_axi_tx_tready to insert idles.