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------------------------------------------------------------------------------

--  This file is a part of the GRLIB VHDL IP LIBRARY

--  Copyright (C) 2003 - 2008, Gaisler Research

--  Copyright (C) 2008 - 2014, Aeroflex Gaisler

--  Copyright (C) 2015 - 2016, Cobham Gaisler

--

--  This program 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 2 of the License, or

--  (at your option) any later version.

--

--  This program 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 this program; if not, write to the Free Software

--  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

-----------------------------------------------------------------------------

-- Entity:      eth_rstgen

-- File:        eth_rstgen.vhd

-- Author:      Jiri Gaisler - Gaisler Research

-- Description: Reset generation with glitch filter

------------------------------------------------------------------------------

library ieee;

use ieee.std_logic_1164.all;

entity eth_rstgen is

  generic (acthigh : integer := 0);

  port (

    rstin     : in  std_ulogic;

    clk       : in  std_ulogic;

    clklock   : in  std_ulogic;

    rstout    : out std_ulogic;

    rstoutraw : out std_ulogic

  );

end;

architecture rtl of eth_rstgen is

signal r : std_logic_vector(4 downto 0);

signal rst : std_ulogic;

attribute equivalent_register_removal : string;

attribute keep                        : string;

attribute equivalent_register_removal of r : signal is "no";

attribute equivalent_register_removal of rst : signal is "no";

attribute keep of r : signal is "true";

attribute keep of rst : signal is "true";

begin

  rst <= not rstin when acthigh = 1 else rstin;

  rstoutraw <= rst;

  reg1 : process (clk, rst) begin

    if rising_edge(clk) then

      r <= r(3 downto 0) & clklock;

      rstout <= r(4) and r(3) and r(2);

    end if;

    if rst = '0' then r <= "00000"; rstout <= '0'; end if;

  end process;

end;