Debouncer

---------------------------------------------------------------------------------- 
-- Company: Digilent Inc 2011 
-- Engineer: Michelle Yu   
-- Create Date:    11:33:37 08/19/2011  
-- 
-- Module Name:    debouncer - Behavioral  
-- Project Name: 	 PmodENC 
-- Target Devices: Nexys 3  
-- Tool versions: Xilinx ISE Design Suite 13.2 
-- 
-- Description:  
--	This file defines a debouncer for eliminating the logic noise presented when the shaft is rotated. 
-- 
-- Revision:  
-- Revision 0.01 - File Created 
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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL; 
 
 
entity Debouncer is 
    Port ( clk : in  STD_LOGIC; 
			-- signals from the pmod 
           Ain : in  STD_LOGIC;  
           Bin : in  STD_LOGIC; 
			-- debounced signals  
			  Aout: out STD_LOGIC; 
			  Bout: out STD_LOGIC 
			  ); 
end Debouncer; 
 
architecture Behavioral of Debouncer is 
 
signal sclk: std_logic_vector (6 downto 0); 
signal sampledA, sampledB : std_logic; 
begin 
 
	process(clk)
		begin 
			if clk'event and clk = '1' then 
				sampledA <= Ain; 
				sampledB <= Bin; 
				-- clock is divided to 1MHz 
				-- samples every 1uS to check if the input is the same as the sample 
				-- if the signal is stable, the debouncer should output the signal 
				if sclk = "1100100" then 
					if sampledA = Ain then  
						Aout <= Ain; 
					end if; 
					if sampledB = Bin then  
						Bout <= Bin; 
					end if; 
					sclk <="0000000"; 
				else 
					sclk <= sclk +1; 
				end if;
			end if;
	end process; 
	 
end Behavioral;