Source file VHDL/Flasher.vhd

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--===========================================================================-- 
--                                                                           -- 
--                    LED Flasher                                            -- 
--                                                                           -- 
--===========================================================================-- 
-- 
--  File name      : flasher.vhd 
-- 
--  Entity name    : flasher 
-- 
--  Purpose        : Implements a long counter used to flash a LED 
--                   to indicate code has loaded correctly 
-- 
--  Dependencies   : ieee.std_logic_1164 
--                   ieee.numeric_std 
--                   ieee.std_logic_unsigned 
-- 
--  Author         : John E. Kent 
-- 
--  Email          : dilbert57 at the domain opencores.org 
-- 
--  Web            : http://opencores.org/project,system09 
-- 
-- 
--  Copyright (C) 2010 John Kent 
-- 
--  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 3 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, see <http://www.gnu.org/licenses/>. 
-- 
--===========================================================================-- 
--                                                                           -- 
--                              Revision  History                            -- 
--                                                                           -- 
--===========================================================================-- 
-- 
-- Version Author        Date         Changes 
-- 
-- 0.1     John Kent     2010-08-28   Made separate module 
-- 
 
library ieee; 
  use ieee.std_logic_1164.all; 
  use ieee.numeric_std.all; 
  use ieee.std_logic_unsigned.all; 
--library unisim; 
--  use unisim.vcomponents.all; 
 
----------------------------------------------------------------------- 
--                    Entity for B3_SRAM                             -- 
----------------------------------------------------------------------- 
 
--* @brief LED Flasher 
--* 
--* @author John E. Kent 
--* @version 0.1 from 2010-08-28 
 
entity flasher is 
  port ( 
    clk      : in  std_logic;           -- Clock input 
    rst      : in  std_logic;           -- Reset input (active high) 
    LED      : out Std_Logic            -- LED output 
  ); 
end flasher; 
 
--================== End of entity ==============================-- 
 
------------------------------------------------------------------------------- 
-- Architecture for Flasher 
------------------------------------------------------------------------------- 
 
--* Implements a long counter used to flash a LED 
--*                   to indicate code has loaded correctly. 
--* 
--* @author John E. Kent 
--* @version 0.1 from 2010-08-28 
 
architecture rtl of  flasher is 
 
-- Flashing LED test signals 
signal countL       : std_logic_vector(23 downto 0); 
 
begin 
 
--* LED Flasher to indicate code has loaded 
my_LED_Flasher : process (clk, rst, CountL ) 
begin 
  if falling_edge(clk) then 
    if rst = '1' then 
      countL <= (others=>'0'); 
    else 
      countL <= countL + 1; 
    end if; 
  end if; 
  LED <= countL(23); 
end process; 
 
end rtl;