Subversion Repositories jt51

/*  This file is part of JT51.

    JT51 is free software: you can redistribute it and/or modify

    it under the terms of the GNU General Public License as published by

    the Free Software Foundation, either version 3 of the License, or

    (at your option) any later version.

    JT51 is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License

    along with JT51.  If not, see <http://www.gnu.org/licenses/>.

        Author: Jose Tejada Gomez. Twitter: @topapate

        Version: 1.0

        Date: 27-10-2016

        */

`timescale 1ns / 1ps

/*

        tab size 4

        See xapp052.pdf from Xilinx

*/

module jt51_noise_lfsr #(parameter init=14220 )(

        input   rst,

        input   clk,

        input   base,

        output  out

);

reg [16:0] bb;

assign out = bb[16];

reg last_base;

always @(posedge clk) begin : base_counter

        if( rst ) begin

                bb                      <= init[16:0];

                last_base       <= 1'b0;

        end

        else begin

                last_base <= base;

                if( last_base != base ) begin

                        bb[16:1]        <= bb[15:0];

                        bb[0]            <= ~(bb[16]^bb[13]);

                end

        end

end

endmodule