------------------------------------------------------------------------
--      BtnDemo.vhd -- Demonstrate D2SB On-Board Button and LED
------------------------------------------------------------------------
-- Author:  Clint Cole
--          Copyright 2003 Digilent, Inc.
------------------------------------------------------------------------
-- This module demonstrates connects the button to the LED on the D2FT board.
--
--  Inputs:
--		btn			- button on the D2-SB board
--
--  Outputs:
--		led			- discrete LED on the D2-SB board
--
------------------------------------------------------------------------
-- Revision History:
--  09/18/2003(ClintC): created
------------------------------------------------------------------------

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity D2SBBtnDemo is
    Port (  btn, mclk : in std_logic;
            led       : out std_logic);
end D2SBBtnDemo;

architecture Behavioral of D2SBBtnDemo is

	------------------------------------------------------------------------
	-- Component Declarations
	------------------------------------------------------------------------
 
	------------------------------------------------------------------------
	-- Signal Declarations
	------------------------------------------------------------------------

    signal cntClk : std_logic_vector(23 downto 0);

	------------------------------------------------------------------------
	-- Module Implementation
	------------------------------------------------------------------------

begin
     
  	process (mclk)							  
  		begin	  					  
              if mclk = '1' and mclk'Event then 
                  cntClk <= cntClk + 1;
              end if;

  	end process;

	led <= cntClk(23) or btn;

end Behavioral;