The following 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.
Figure 1. Transmitting a Message with NFC Idles Inserted
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.