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//

// clk_rst.v -- clock and reset generator

//

`timescale 1ns/10ps

`default_nettype none

module clk_rst(clk_in, rst_in,

               ddr_clk_0, ddr_clk_90, ddr_clk_180,

               ddr_clk_270, ddr_clk_ok, clk, rst);

    input clk_in;

    input rst_in;

    output ddr_clk_0;

    output ddr_clk_90;

    output ddr_clk_180;

    output ddr_clk_270;

    output ddr_clk_ok;

    output clk;

    output rst;

  wire clk50_in;

  wire clk50_out;

  wire clk50_ok;

  wire clk100_out;

  wire clk100_in;

  wire clk100_0;

  wire clk100_90;

  wire clk100_180;

  wire clk100_270;

  wire clk100_ok;

  reg rst_p;

  reg rst_s;

  reg [23:0] rst_counter;

  wire rst_counting;

  //------------------------------------------------------------

  IBUFG clk_in_buffer(

    .I(clk_in),

    .O(clk50_in)

  );

  DCM_SP dcm50(

    .RST(1'b0),

    .CLKIN(clk50_in),

    .CLKFB(clk),

    .CLK0(clk50_out),

    .CLK2X(clk100_out),

    .LOCKED(clk50_ok),

    .PSCLK(1'b0),

    .PSEN(1'b0),

    .PSINCDEC(1'b0)

  );

  defparam dcm50.CLKDV_DIVIDE = 2.0;

  defparam dcm50.CLKFX_DIVIDE = 1;

  defparam dcm50.CLKFX_MULTIPLY = 4;

  defparam dcm50.CLKIN_DIVIDE_BY_2 = "FALSE";

  defparam dcm50.CLKIN_PERIOD = 20.0;

  defparam dcm50.CLKOUT_PHASE_SHIFT = "NONE";

  defparam dcm50.CLK_FEEDBACK = "1X";

  defparam dcm50.DESKEW_ADJUST = "SYSTEM_SYNCHRONOUS";

  defparam dcm50.DLL_FREQUENCY_MODE = "LOW";

  defparam dcm50.DUTY_CYCLE_CORRECTION = "TRUE";

  defparam dcm50.PHASE_SHIFT = 0;

  defparam dcm50.STARTUP_WAIT = "FALSE";

  BUFG clk50_buffer(

    .I(clk50_out),

    .O(clk)

  );

  BUFG clk100_buffer(

    .I(clk100_out),

    .O(clk100_in)

  );

  //------------------------------------------------------------

  DCM_SP dcm100(

    .RST(~clk50_ok),

    .CLKIN(clk100_in),

    .CLKFB(ddr_clk_0),

    .CLK0(clk100_0),

    .CLK90(clk100_90),

    .CLK180(clk100_180),

    .CLK270(clk100_270),

    .LOCKED(clk100_ok),

    .PSCLK(1'b0),

    .PSEN(1'b0),

    .PSINCDEC(1'b0)

  );

  defparam dcm100.CLKDV_DIVIDE = 2.0;

  defparam dcm100.CLKFX_DIVIDE = 1;

  defparam dcm100.CLKFX_MULTIPLY = 4;

  defparam dcm100.CLKIN_DIVIDE_BY_2 = "FALSE";

  defparam dcm100.CLKIN_PERIOD = 10.0;

  defparam dcm100.CLKOUT_PHASE_SHIFT = "NONE";

  defparam dcm100.CLK_FEEDBACK = "1X";

  defparam dcm100.DESKEW_ADJUST = "SYSTEM_SYNCHRONOUS";

  defparam dcm100.DLL_FREQUENCY_MODE = "LOW";

  defparam dcm100.DUTY_CYCLE_CORRECTION = "TRUE";

  defparam dcm100.PHASE_SHIFT = 0;

  defparam dcm100.STARTUP_WAIT = "FALSE";

  BUFG clk100_0_buffer(

    .I(clk100_0),

    .O(ddr_clk_0)

  );

  BUFG clk100_90_buffer(

    .I(clk100_90),

    .O(ddr_clk_90)

  );

  BUFG clk100_180_buffer(

    .I(clk100_180),

    .O(ddr_clk_180)

  );

  BUFG clk100_270_buffer(

    .I(clk100_270),

    .O(ddr_clk_270)

  );

  assign ddr_clk_ok = clk100_ok;

  //------------------------------------------------------------

  assign rst_counting = (rst_counter == 24'hFFFFFF) ? 0 : 1;

  always @(posedge clk) begin

    rst_p <= rst_in;

    rst_s <= rst_p;

    if (rst_s | ~clk50_ok | ~clk100_ok) begin

      rst_counter <= 24'h000000;

    end else begin

      if (rst_counting == 1) begin

        rst_counter <= rst_counter + 1;

      end

    end

  end

  assign rst = rst_counting;

endmodule