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VHDL for FPGA Design

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Decoder

VHDL for FPGA Design

 

Decoder VHDL Code

edit 
 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use ieee.numeric_std.all;
 
entity Decoder is
   port(E : in std_logic;
        din : in std_logic_vector(2 downto 0);
        dout : out std_logic_vector(7 downto 0));
end Decoder;
 
architecture descript of Decoder is
begin
   
   dout <="00000000" when E='0' else
        "00000001" when E='1' and din="000" else
        "00000010" when E='1' and din="001" else
        "00000100" when E='1' and din="010" else
        "00001000" when E='1' and din="011" else
        "00010000" when E='1' and din="100" else
        "00100000" when E='1' and din="101" else
        "01000000" when E='1' and din="110" else
        "10000000" when E='1' and din="111";

end descript;

Decoder Testbench File

edit 
LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
 
-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
USE ieee.numeric_std.ALL;
 
ENTITY tb_Decoder IS
END tb_Decoder;
 
ARCHITECTURE behavior OF tb_Decoder IS 
 
    -- Component Declaration for the Unit Under Test (UUT)
 
    COMPONENT Decoder
    PORT(
         E : IN  std_logic;
         din : IN  std_logic_vector(2 downto 0);
         dout : OUT  std_logic_vector(7 downto 0)
        );
    END COMPONENT;
    

   --Inputs
   signal E : std_logic := '0';
   signal din : std_logic_vector(2 downto 0) := (others => '0');

 	--Outputs
   signal dout : std_logic_vector(7 downto 0);
   -- No clocks detected in port list. Replace clk below with 
   -- appropriate port name 
 
	signal clk : std_logic;
	constant clk_period : time := 10 ns;
 
BEGIN
 
	-- Instantiate the Unit Under Test (UUT)
   uut: Decoder PORT MAP (
          E => E,
          din => din,
          dout => dout
        );

   -- Clock process definitions
   clk_process :process
   begin
		clk <= '0';
		wait for clk_period/2;
		clk <= '1';
		wait for clk_period/2;
   end process;
 
	
   -- Stimulus process
   stim_proc: process
   begin		
      -- hold reset state for 100 ns.
      wait for 100 ns;	
		din <= "001";
		wait for clk_period;
		din <= "010";
		wait for clk_period;
		din <= "011";
		wait for clk_period;
		din <= "100";
		wait for clk_period;
		din <= "101";
		wait for clk_period;
		din <= "110";
		wait for clk_period;
		din <= "111";
		wait for clk_period;
		E <= '1';
		wait for clk_period;		
		din <= "000";
		wait for clk_period;
		din <= "001";
		wait for clk_period;
		din <= "010";
		wait for clk_period;
		din <= "011";
		wait for clk_period;
		din <= "100";
		wait for clk_period;
		din <= "101";
		wait for clk_period;
		din <= "110";
		wait for clk_period;
		din <= "111";
		
      -- insert stimulus here 

      wait;
   end process;

END;

Decoder Simulation Waveform

edit 
 
edit

Video of how to get to the Decoder RTL Schematic (circuit diagram) in the Xilinx ISE Project Navigator

See Also

edit


This page or section is an undeveloped draft or outline.
You can help to develop the work, or you can ask for assistance in the project room.


Multiplexer

VHDL for FPGA Design

Multiplexer VHDL Code

edit 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity Multiplexer_VHDL is
   port
   (
      a, b, c, d, e, f, g, h : in std_logic; 
      Sel : in std_logic_vector(2 downto 0);

      Output : out std_logic
   );
end entity Multiplexer_VHDL;
 
architecture Behavioral of Multiplexer_VHDL is
begin 
   process (a, b, c, d, e, f, g, h, Sel) is
   begin
      case Sel is
         when "000"  => Output <= a;
         when "001"  => Output <= b;
         when "010"  => Output <= c;
         when "011"  => Output <= d;
         when "100"  => Output <= e;
         when "101"  => Output <= f;
         when "110"  => Output <= g;
         when others => Output <= h;
      end case;
   end process;
end architecture Behavioral;

Multiplexer Testbench Code

edit 
LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
 
-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
USE ieee.numeric_std.ALL;
 
ENTITY tb_Multiplexer IS
END tb_Multiplexer;
 
ARCHITECTURE behavior OF tb_Multiplexer IS 
 
    -- Component Declaration for the Unit Under Test (UUT)
 
    COMPONENT Multiplexer_VHDL
    PORT(
         a : IN  std_logic;
         b : IN  std_logic;
         c : IN  std_logic;
         d : IN  std_logic;
         e : IN  std_logic;
         f : IN  std_logic;
         g : IN  std_logic;
         h : IN  std_logic;
         Sel : IN  std_logic_vector(2 downto 0);
         Output : OUT  std_logic
        );
    END COMPONENT;
    

   --Inputs
   signal a : std_logic := '0';
   signal b : std_logic := '0';
   signal c : std_logic := '0';
   signal d : std_logic := '0';
   signal e : std_logic := '0';
   signal f : std_logic := '0';
   signal g : std_logic := '0';
   signal h : std_logic := '0';
   signal Sel : std_logic_vector(2 downto 0) := (others => '0');

 	--Outputs
   signal Output : std_logic;
   -- No clks detected in port list. Replace clk below with 
   -- appropriate port name 
 
	signal clk : std_logic;
	constant clk_period : time := 10 ns;
	signal counter : std_logic_vector(7 downto 0) := (others => '0'); 
	
BEGIN
 
	-- Instantiate the Unit Under Test (UUT)
   uut: Multiplexer_VHDL PORT MAP (
          a => a,
          b => b,
          c => c,
          d => d,
          e => e,
          f => f,
          g => g,
          h => h,
          Sel => Sel,
          Output => Output
        );

   -- clk process definitions
   clk_process :process
   begin
		clk <= '0';
		wait for clk_period/2;
		clk <= '1';
		wait for clk_period/2;
   end process;
 
	a <= counter(0);
	b <= counter(1);
	c <= counter(2);
	d <= counter(3);
	e <= counter(4);
	f <= counter(5);
	g <= counter(6);
	h <= counter(7);
	
   -- Stimulus process
   stim_proc: process
   begin		
      -- hold reset state for 100 ns.
		wait for 100 ns;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00000001";
		Sel <= "000";
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00000010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00000011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00000100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00000101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00000111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00001111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00010111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00011111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00100111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00101111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00110111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "00111111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01000111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01001111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01010111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01011111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01100111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01101111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01110111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "01111111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10000001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10000010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10000011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10000100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10000101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10000111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10001111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10010111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10011111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10100111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10101111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10110111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "10111111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11000111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11001111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11010111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11011111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11100111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11101111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11110111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111000";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111001";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111010";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111011";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111100";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111101";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111110";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		wait for clk_period;
		counter <= "11111111";		
		Sel <= "000";		
		wait for clk_period;
		Sel <= "001";
		wait for clk_period;
		Sel <= "010";
		wait for clk_period;
		Sel <= "011";
		wait for clk_period;
		Sel <= "100";
		wait for clk_period;
		Sel <= "101";
		wait for clk_period;
		Sel <= "110";
		wait for clk_period;
		Sel <= "111";
		
      -- insert stimulus here 

      wait;
   end process;

END;

Multiplexer Simulation Waveform

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Priority Encoder

VHDL for FPGA Design

Priority Encoder

edit 
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.STD_LOGIC_UNSIGNED.all;

ENTITY encoder74 IS							
	PORT 	(clk,res,sin :IN STD_LOGIC;	
			outpt :OUT STD_LOGIC);		
END encoder74 ;							

ARCHITECTURE struc OF encoder74 IS 
			SIGNAL txlss : STD_LOGIC_VECTOR(3 downto 1);

BEGIN
PROCESS
BEGIN

WAIT UNTIL FALLING_EDGE (clk);
		IF (res = '1') THEN			
			txlss <= "000";
		ELSIF (res = '0') THEN
			txlss(1) <= inpt;
			txlss(2) <= txlss(1);
			txlss(3) <= txlss(2);
			outpt<= (sin XOR txlss(2) XOR txlss(3));
END IF;
END PROCESS;
END struc;

Simulation Waveform

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Generated Logic Circuit

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4-Bit Adder

VHDL for FPGA Design

library ieee; use ieee.std_logic_1164.all; use ieee.std_logic_unsigned.all use ieee.std_logic_arith.all;

Entity Adder4 Is port ( a,b:in integer Range -8 to 7; sum:out integer Range -16 to 15 ); end Adder4;

Architecture Adder4arch of Adder4 Is Begin sum<=a+b;

end Adder4arch;

Simulation Waveform

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library ieee;
use ieee.std_logic_1164.all;
use work.all;

entity adder4b is
  port (a,b,c:in std_logic_vector(3 downto 0);
        cin:in std_logic;
        cout:out std_logic;
        s:out std_logic_vector(3 downto 0));
END adder4b;

architecture arch12 of adder is
  signal y:std_logic_vector(4 downto 0);
begin
  y(0)<= cin;
  cout<=y(4);
  --u:for i in 0 to 3 generate
  --p:entity work.FA(arch) port map(a,b,c,s,r=>y(i+1));
  p0:entity work.FA(arch) port map(a=>a(0),b=>b(0),c=>y(0),s=>s(0),r=>y(1));
  p1:entity work.FA(arch) port map(a=>a(1),b=>b(1),c=>y(1),s=>s(1),r=>y(2));
  p2:entity work.FA(arch) port map(a=>a(2),b=>b(2),c=>y(2),s=>s(2),r=>y(3));
  p3:entity work.FA(arch) port map(a=>a(3),b=>b(3),c=>y(3),s=>s(3),r=>y(4));
--end generate;


4-Bit Multiplier

VHDL for FPGA Design

Design of 4×4-Bit Multiplier VHDL Code

edit 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;

entity Multiplier_VHDL is
   port
   (
      Nibble1, Nibble2: in std_logic_vector(1 downto 0);

      Result: out std_logic_vector(2 downto 0)
   );
end Multiplier_VHDL;

architecture Behavioral of Multiplier_VHDL is
begin

   Result <= std_logic_vector(unsigned(Nibble1) * unsigned(Nibble2));

end Behavioral;

Simulation Waveform

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4-Bit ALU

VHDL for FPGA Design

4-Bit ALU VHDL Code

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A combinatorial ALU with the following operations:

Operation Result Flag Description
000 Nibble1 + Nibble2 Carry = Overflow Addition
001 | Nibble1 - Nibble2 | 1 if Nibble2 > Nibble1,
0 otherwise 		Test / diff
010 Nibble1 AND Nibble2 0 Bitwise AND
011 Nibble1 OR Nibble2 0 Bitwise OR
100 Nibble1 XOR Nibble2 0 Bitwise XOR
101 15 - Nibble1 0 Bitwise inverse of Nibble1
110 15 - Nibble2 0 Bitwise inverse of Nibble2
111 Nibble1 + Nibble2 + 1 Carry = Overflow Addition 
 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;
 
entity ALU_VHDL is
   port
   (
      Nibble1, Nibble2 : in std_logic_vector(3 downto 0);
      Operation : in std_logic_vector(2 downto 0);

      Carry_Out : out std_logic;
      Flag : out std_logic;
      Result : out std_logic_vector(3 downto 0)
   );
end entity ALU_VHDL;
 
architecture Behavioral of ALU_VHDL is

   signal Temp: std_logic_vector(4 downto 0);

begin

   process(Nibble1, Nibble2, Operation, temp) is
   begin
      Flag <= '0';
      case Operation is
 	 when "000" => -- res = nib1 + nib2, flag = carry = overflow
 	    Temp   <= std_logic_vector((unsigned("0" & Nibble1) + unsigned(Nibble2)));
            Result <= temp(3 downto 0);
 	    Carry_Out   <= temp(4);
 	 when "001" => -- res = |nib1 - nib2|, flag = 1 iff nib2 > nib1
 	    if (Nibble1 >= Nibble2) then
 	       Result <= std_logic_vector(unsigned(Nibble1) - unsigned(Nibble2));
 	       Flag   <= '0';
            else
 	       Result <= std_logic_vector(unsigned(Nibble2) - unsigned(Nibble1));
 	       Flag   <= '1';
            end if;
 	 when "010" =>
 	    Result <= Nibble1 and Nibble2;
 	 when "011" =>
 	    Result <= Nibble1 or Nibble2;
 	 when "100" =>
 	    Result <= Nibble1 xor Nibble2;
 	 when "101" =>
 	    Result <= not Nibble1;
  	 when "110" =>
            Result <= not Nibble2;
 	 when others => -- res = nib1 + nib2 + 1, flag = 0
 	    Temp   <= std_logic_vector((unsigned("0" & Nibble1) + unsigned(not Nibble2)) + 1);
 	    Result <= temp(3 downto 0);
 	    Flag   <= temp(4);
      end case;
   end process;

end architecture Behavioral;

Simulation Waveform

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Generated Symbol

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D Flip Flop

VHDL for FPGA Design

Synchronous Positive Edge Triggered D Flip-Flop with Active-High Reset, Preset, and Clock Enable

edit 
 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity D_FF_VHDL is
   port
   (
      clk : in std_logic;

      rst : in std_logic;
      pre : in std_logic;
      ce  : in std_logic;
      
      d : in std_logic;

      q : out std_logic
   );
end entity D_FF_VHDL;
 
architecture Behavioral of D_FF_VHDL is

begin
   process (clk) is
   begin
      if rising_edge(clk) then  
         if (rst='1') then   
            q <= '0';
         elsif (pre='1') then
            q <= '1';
         elsif (ce='1') then
            if (d ='1') then
             q <= '1';
         elsif (d ='0') then 
             q<= '0';
            end if;
         end if;
      end if;
   end process;
end architecture Behavioral;

Simulation Results

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Generated Symbol

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 File:D FF SCH F.png


T Flip Flop

VHDL for FPGA Design

Synchronous Positive edge T Flip-Flop with Reset and Clock enable

edit 
 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity t_trigger is
   port (T,Reset,CLK,CLK_enable: in std_logic;
	 Q: out std_logic);
end t_trigger;
 
architecture beh_t_trigger of t_trigger is	 

begin
    process (Reset,CLK) 
    variable  temp: std_logic;
    begin
        if (rising_edge(CLK)) then    --sometimes you need to include a package for rising_edge, you can use CLK'EVENT AND CLK = '1' instead
            if Reset='1' then   
                temp := '0';  		
            elsif CLK_enable ='1' then
                temp := T xor temp;
            end if;
        end if; 
    Q <= temp;	   
    end process;
end beh_t_trigger;

Simulation Results

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Generated Symbol

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 File:T FF SCH F.png


JK Flip Flop

VHDL for FPGA Design

Synchronous Positive edge JK Flip-Flop with Reset and Clock enable

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

entity JK_FF_VHDL is
   port( J,K: in  std_logic;
         Reset: in std_logic;
         Clock_enable: in std_logic;
         Clock: in std_logic;
         Output: out std_logic);
end JK_FF_VHDL;

architecture Behavioral of JK_FF_VHDL is
   signal temp: std_logic;
begin
   process (Clock) 
   begin
      if rising_edge(Clock) then                 
         if Reset='1' then   
            temp <= '0';
         elsif Clock_enable ='1' then
            if (J='0' and K='0') then
               temp <= temp;
            elsif (J='0' and K='1') then
               temp <= '0';
            elsif (J='1' and K='0') then
               temp <= '1';
            elsif (J='1' and K='1') then
               temp <= not (temp);
            end if;
         end if;
      end if;
   end process;
   Output <= temp;
end Behavioral;

Simulation Results

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Generated Symbol

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4-Bit Binary Counter with Parallel Load

VHDL for FPGA Design
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity Counter is
Port(clk : in STD_LOGIC;
   Reset : in STD_LOGIC;
   Count : out STD_LOGIC_VECTOR (2 downto 0));
end Counter;
architecture Behavioral of Counter is
signal count_int : std_logic_vector(2 downto 0);
begin
process (reset, clk)
begin
 if reset = '1' then
  count_int <= "111";
 elsif clk'event and clk = '1' then
  if count_int <= "111" and count_int > "010" then
    count_int <= count_int - "1";
  else
    count_int <= "111";
  end if;
 end if;
end process;
count <= count_int;
end Behavioral;

Simulation Results

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4-Bit BCD Counter with Clock Enable

VHDL for FPGA Design

4-Bit BCD Up Counter with Clock Enable

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

entity Counter2_VHDL is 
   port( Clock_enable_B: in std_logic;
 	 Clock: in std_logic;
 	 Reset: in std_logic;
 	 Output: out std_logic_vector(0 to 3));
end Counter2_VHDL;
 
architecture Behavioral of Counter2_VHDL is
   signal temp: std_logic_vector(0 to 3);
begin   process(Clock,Reset)
   begin
      if Reset='1' then
         temp <= "0000";
      elsif(rising_edge(Clock)) then
         if Clock_enable_B='0' then
            if temp="1001" then
               temp<="0000";
            else
               temp <= temp + 1;
            end if;
         end if;
      end if;
   end process;
   Output <= temp;
end Behavioral;

Simulation Results

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4-Bit Shift Register

VHDL for FPGA Design

4-Bit Shift Register

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

entity Shift_register_VHDL is

   port( clk: in std_logic;
 	 L: in std_logic; 
 	 w: in std_logic; -- new data to shift in
 	 Output: out std_logic_vector(3 downto 0);
 	 Input: in std_logic_vector( 3 downto 0));

end Shift_register_VHDL;

architecture Behavioral of Shift_register_VHDL is
begin
   process
   variable temp: std_logic_vector(3 downto 0); 
   begin
      wait until rising_edge (clk);
      temp := Input; 
      if L='1' then 
         for i in 0 to 2 loop
            temp(i) := temp(i+1);
         end loop;
         temp(3) := w;
      end if;
      Output <= temp;
    end process;
end Behavioral;

Simulation results

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4-Bit Johnson Counter with Reset

 

Johnson Counter

edit 
library ieee;
use ieee.std_logic_1164.ALL;
use ieee.numeric_std.ALL;
library UNISIM;
use UNISIM.Vcomponents.ALL;

entity Johnson is
   port ( CLK : in    std_logic; 
          CLR : in    std_logic; 
          A   : out   std_logic; 
          B   : out   std_logic; 
          C   : out   std_logic; 
          D   : out   std_logic);
end Johnson;

architecture BEHAVIORAL of Johnson is
   attribute INIT       : string ;
   attribute BOX_TYPE   : string ;
   signal XLXN_44 : std_logic;
   signal A_DUMMY : std_logic;
   signal B_DUMMY : std_logic;
   signal C_DUMMY : std_logic;
   signal D_DUMMY : std_logic;
   component FDC
      -- synopsys translate_off
      generic( INIT : bit :=  '0');
      -- synopsys translate_on
      port ( C   : in    std_logic; 
             CLR : in    std_logic; 
             D   : in    std_logic; 
             Q   : out   std_logic);
   end component;
   attribute INIT of FDC : component is "0";
   attribute BOX_TYPE of FDC : component is "BLACK_BOX";
   
   component INV
      port ( I : in    std_logic; 
             O : out   std_logic);
   end component;
   attribute BOX_TYPE of INV : component is "BLACK_BOX";
   
begin
   A <= A_DUMMY;
   B <= B_DUMMY;
   C <= C_DUMMY;
   D <= D_DUMMY;
   XLXI_20 : FDC
      port map (C=>CLK,
                CLR=>CLR,
                D=>XLXN_44,
                Q=>A_DUMMY);
   
   XLXI_21 : FDC
      port map (C=>CLK,
                CLR=>CLR,
                D=>A_DUMMY,
                Q=>B_DUMMY);
   
   XLXI_22 : FDC
      port map (C=>CLK,
                CLR=>CLR,
                D=>B_DUMMY,
                Q=>C_DUMMY);
   
   XLXI_23 : FDC
      port map (C=>CLK,
                CLR=>CLR,
                D=>C_DUMMY,
                Q=>D_DUMMY);
   
   XLXI_25 : INV
      port map (I=>D_DUMMY,
                O=>XLXN_44);
   
end BEHAVIORAL;

Simulation Waveform

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State-Machine Design Example Asynchronous Counter

VHDL for FPGA Design

Asynchronous Counter

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State Diagram

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Simulation Waveform

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State-Machine Design Example Serial Parity Generator

VHDL for FPGA Design

Serial Parity Generator

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State Diagram

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Simulation Waveform

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Example Application Serial Adder

Serial Adder

edit 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity SA_VHDL is
   Port ( I : in std_logic_vector(15 downto 0);
          O : out std_logic_vector(7 downto 0);
          c_i, a_i, b_i, c_o, s_o : out std_logic;
          CLK : in std_logic;
          Load : in std_logic);
end SA_VHDL;

architecture Behavioral of SA_VHDL is
   signal ina, inb, oreg : std_logic_vector(7 downto 0);
   signal so, ci, co: std_logic;
begin

--rec ina
process (CLK)
begin
   if CLK'event and CLK='1' then
      if (Load='1') then
         ina <= I(15 downto 8);
      else
         ina <= '0' & ina(7 downto 1);
      end if;
   end if;
end process;

--reg inb
process (CLK)
begin
   if CLK'event and CLK='1' then
      if (Load='1') then
         inb <= I(7 downto 0);
      else
         inb <= '0' & inb(7 downto 1);
      end if;
   end if;
end process;

--oreg 
process (CLK)
begin
   if CLK'event and CLK='1' then
      if (Load='1') then
         oreg <= "00000000";
         ci <= '0';
      else
         ci <= co;
         oreg <= so & oreg(7 downto 1);
      end if;
   end if;
end process;

-- FA
so <=  inb(0) xor ina(0) xor ci;
co <= (inb(0) and ina(0)) or  
      (inb(0) and ci) or 
      (ci and ina(0));

O <= oreg;

-- for  test
c_i <= ci;  
a_i <= ina(0);
b_i <= inb(0);

c_o <= co;  
s_o <= so; 

end Behavioral;

Simulation Results

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