// ***************************************************************************
// ***************************************************************************
// Copyright 2014 - 2017 (c) Analog Devices, Inc. All rights reserved.
//
// Each core or library found in this collection may have its own licensing terms. 
// The user should keep this in in mind while exploring these cores. 
//
// Redistribution and use in source and binary forms,
// with or without modification of this file, are permitted under the terms of either
//  (at the option of the user):
//
//   1. The GNU General Public License version 2 as published by the
//      Free Software Foundation, which can be found in the top level directory, or at:
// https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html
//
// OR
//
//   2.  An ADI specific BSD license as noted in the top level directory, or on-line at:
// https://github.com/analogdevicesinc/hdl/blob/dev/LICENSE
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// ***************************************************************************
// ***************************************************************************

`timescale 1ns / 1ps

module debouncer
//----------- Paramters Declarations -------------------------------------------
#(
    parameter DEBOUNCER_LENGTH = 4
)
//----------- Ports Declarations -----------------------------------------------
(
    input       clk_i,
    input       rst_i,
    input       sig_i,
    output reg  sig_o
);
//------------------------------------------------------------------------------
//----------- Registers Declarations -------------------------------------------
//------------------------------------------------------------------------------
reg [DEBOUNCER_LENGTH-1:0] shift_reg;

//------------------------------------------------------------------------------
//----------- Assign/Always Blocks ---------------------------------------------
//------------------------------------------------------------------------------

always @(posedge clk_i)
begin
    if(rst_i == 1)
    begin
        shift_reg   <= 0;
        sig_o       <= 0;
    end
    else
    begin
        shift_reg <= {shift_reg[DEBOUNCER_LENGTH-2:0], sig_i};
        if(shift_reg == {DEBOUNCER_LENGTH{1'b1}})
        begin
            sig_o <= 1'b1;
        end
        else if(shift_reg == {DEBOUNCER_LENGTH{1'b0}})
        begin
            sig_o <= 1'b0;
        end
    end
end

endmodule