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// ***************************************************************************
// ***************************************************************************
// Copyright 2013(c) Analog Devices, Inc.
// Author: Lars-Peter Clausen <lars@metafoo.de>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
// - Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// - Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in
// the documentation and/or other materials provided with the
// distribution.
// - Neither the name of Analog Devices, Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
// - The use of this software may or may not infringe the patent rights
// of one or more patent holders. This license does not release you
// from the requirement that you obtain separate licenses from these
// patent holders to use this software.
// - Use of the software either in source or binary form, must be run
// on or directly connected to an Analog Devices Inc. component.
//
// THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED.
//
// IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY
// RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// ***************************************************************************
// ***************************************************************************
module fifo_address_sync (
input clk,
input resetn,
input m_axis_ready,
output reg m_axis_valid,
output reg [ADDRESS_WIDTH-1:0] m_axis_raddr,
output [ADDRESS_WIDTH:0] m_axis_level,
output reg s_axis_ready,
input s_axis_valid,
output reg s_axis_empty,
output reg [ADDRESS_WIDTH-1:0] s_axis_waddr,
output [ADDRESS_WIDTH:0] s_axis_room
);
parameter ADDRESS_WIDTH = 4;
reg [ADDRESS_WIDTH:0] room = 2**ADDRESS_WIDTH;
reg [ADDRESS_WIDTH:0] level = 'h00;
reg [ADDRESS_WIDTH:0] level_next;
assign s_axis_room = room;
assign m_axis_level = level;
wire read = m_axis_ready & m_axis_valid;
wire write = s_axis_ready & s_axis_valid;
always @(posedge clk)
begin
if (resetn == 1'b0) begin
s_axis_waddr <= 'h00;
m_axis_raddr <= 'h00;
end else begin
if (write)
s_axis_waddr <= s_axis_waddr + 1'b1;
if (read)
m_axis_raddr <= m_axis_raddr + 1'b1;
end
end
always @(*)
begin
if (read & ~write)
level_next <= level - 1'b1;
else if (~read & write)
level_next <= level + 1'b1;
else
level_next <= level;
end
always @(posedge clk)
begin
if (resetn == 1'b0) begin
m_axis_valid <= 1'b0;
s_axis_ready <= 1'b0;
level <= 'h00;
room <= 2**ADDRESS_WIDTH;
s_axis_empty <= 'h00;
end else begin
level <= level_next;
room <= 2**ADDRESS_WIDTH - level_next;
m_axis_valid <= level_next != 0;
s_axis_ready <= level_next != 2**ADDRESS_WIDTH;
s_axis_empty <= level_next == 0;
end
end
endmodule
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