Xilinx UG144 manual Interfaces, Transmit Fifo, Appendix a Using the Client-Side Fifo

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Appendix A: Using the Client-Side FIFO

Interfaces

Transmit FIFO

Table A-1describes the transmit FIFO client interface. For more information on the MAC client interface, see “Transmitting Outbound Frames,” on page 47.

Table A-1:Transmit FIFO Client Interface

Signal	Direction	Clock	Description
		Domain
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-2describes the transmit FIFO LocalLink interface. For more information on the LocalLink interface see “Overview of LocalLink Interface,” on page 130.

Table A-2:Transmit FIFO LocalLink Interface

Signal	Direction	Clock	Description
		Domain
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

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		UG144 April 24, 2009