Xilinx LogiCORE IP MAC v8.5, Руководство пользователя

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128 www.xilinx.com 1-Gigabit Ethernet MAC v8.5 User Guide
UG144 April 24, 2009
Appendix A: Using the Client-Side FIFO
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Interfaces
Transmit FIFO
Table A-1 describes the transmit FIFO client interface. For more information on the MAC
client interface, see “Transmitting Outbound Frames,” on page 47 .
Table A-2 describes the transmit FIFO LocalLink interface. For more information on the
LocalLink interface see “Overview of LocalLink Interface,” on page 130 .
Table A-1: Transmit FIFO Client Interface
Signal Direction
Clock
Domain
Description
tx_clk Input N/A Transmit clock used by MAC.
tx_reset Input tx_clk Synchronous reset.
tx_enable Input tx_clk Clock enable for tx_clk. Tie to logic 1
when using GEMAC.
tx_data[7:0] Output tx_clk Data presented t o MAC for
transmission.
tx_data_valid Output tx_clk Valid signal for data.
tx_ack Input tx_clk Ack signal from MAC.
tx_underrun Output tx_clk Underrun signal to MAC.
tx_collision Input tx_clk Collision indication from MAC. Tie
to logic 0 when using GEMAC.
tx_retransmit Input tx_clk Retransmit request from MAC. Tie to
logic 0 when using GEMAC.
Table A-2: Transmit FIFO LocalLink Interface
Signal Direction
Clock
Domain
Description
tx_ll_clock Input N/A Write clock for LocalLink interface
tx_ll_reset Input tx_ll_clock Synchronous reset
tx_ll_data_in[7:0] Input tx_ll_clock Write data to be sent to transmitter
tx_ll_sof_in_n Input tx_ll_clock Start of frame indicator
tx_ll_eof_in_n Input tx_ll_clock End of frame indicator
tx_ll_src_rdy_in_n Input tx_ll_clock Source ready indicator
tx_ll_dst_rdy_out_n Output tx_ll_clock Destination ready indicator
tx_fifo_status[3:0] Output tx_ll_clock FIFO memory status
tx_overflow Output tx_ll_clock Overflow signal indicates when a
frame has been dropped in the FIFO