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//======================================================================
//
// reset_replicator.v
// ------------------
//
// Generates localized copies of the system-wide reset so that each core can
// have its own copy. This way there's more room for the placer to do its job.
//
// Author: Pavel Shatov
// Copyright (c) 2016, 2018-2019 NORDUnet A/S 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 the NORDUnet nor the names of its contributors may
// be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
// IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
// PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
// TO, 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 reset_replicator
(
sys_clk_in,
sys_rst_n_in,
sys_rst_n_out
);
//
// Parameters
//
parameter integer SHREG_WIDTH = 8;
parameter integer FANOUT_WIDTH = 8;
//
// Ports
//
input sys_clk_in;
input sys_rst_n_in;
output [FANOUT_WIDTH-1:0] sys_rst_n_out;
//
// Internals
//
wire [FANOUT_WIDTH-1:0] sys_rst_int;
//
// Localized Reset Replication
//
genvar i;
generate for (i=0; i<FANOUT_WIDTH; i=i+1)
//
begin : gen_sys_rst_n_out
//
LUT1 #(.INIT(2'b01)) LUT1_inst
( .I0(sys_rst_n_in),
.O(sys_rst_int[i])
);
//
(* SHREG_EXTRACT="NO" *)
(* EQUIVALENT_REGISTER_REMOVAL="NO" *)
reg [SHREG_WIDTH-1:0] sys_rst_n_shreg_copy = {SHREG_WIDTH{1'b0}};
//
always @(posedge sys_clk_in or posedge sys_rst_int[i])
//
if (sys_rst_int[i]) sys_rst_n_shreg_copy <= {SHREG_WIDTH{1'b0}};
else sys_rst_n_shreg_copy <= {sys_rst_n_shreg_copy[SHREG_WIDTH-2:0], 1'b1};
//
assign sys_rst_n_out[i] = sys_rst_n_shreg_copy[SHREG_WIDTH-1];
//
end
//
endgenerate
endmodule
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