Receiving Data - 12.0 English

Aurora 64B/66B LogiCORE IP Product Guide (PG074)

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12.0 English

Because the core has no built-in buffer for user data, there is no m_axi_rx_tready signal on the RX AXI4-Stream interface. User application control of the flow of data from an Aurora 64B/66B channel is limited to one of the optional core flow control features.

The m_axi_rx_tvalid signal is asserted concurrently with the first word of each frame from the core. The m_axi_rx_tlast signal is asserted concurrently with the last word or partial word of each frame. The m_axi_rx_tkeep port indicates the number of valid bytes in the final word of each frame using the same byte indication procedure as s_axi_tx_tkeep. All bytes valid are indicated (all 1s) when m_axi_rx_tlast is not asserted and the exact number of bytes valid is specified when m_axi_rx_tlast is asserted.

If the CRC option is selected, the received data stream is computed for the expected CRC value. The CRC block re-calculates the m_axi_rx_tkeep value and correspondingly asserts m_axi_rx_tlast.

The core can deassert m_axi_rx_tvalid anytime, even during a frame.