The Aurora 64B/66B core samples the data only if both s_axi_tx_tready and s_axi_tx_tvalid are asserted. The user application can deassert s_axi_tx_tvalid on any clock cycle ( This Figure ) to ignore the AXI4-Stream input for that cycle. If this occurs in the middle of a frame, idle symbols are sent through the Aurora 64B/66B channel.
The AXI4-Stream data is only valid when it is framed. Data outside of a frame is ignored. To end a frame, assert s_axi_tx_tlast while the last word (or partial word) of data is on the s_axi_tx_tdata port and use s_axi_tx_tkeep to specify the number of valid bytes in the last data beat.
High priority is assigned to these requests for any type of transfer:
• TXDATAVALID deasserted from the transceiver TX interface (1 cycle)
• CC transmission (8 cycles)