DE2 Quartus debounced circuit

Hi Daixiwen and thanks,

Sorry for a long time no answer. Finally solved the problem. using the following code:

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

entity debounce is

generic(

counter_size : INTEGER := 19); --counter size (19 bits gives 10.5ms with 50MHz clock)

port(

Digit : out std_logic_vector (6 downto 0); -- 7 seg digit

hex_count : out std_logic_vector(3 downto 0); -- Hexadecimal result

clk, reset, button : in std_logic; --input signals

Digit_en : out std_logic); -- 7 seg digit enable

end debounce;

architecture logic of debounce is

signal counter : std_logic_vector(3 downto 0) :=(others => '0'); --initializing count to zero.

signal flipflops : std_logic_vector(1 downto 0); --input flip flops

signal counter_out : std_logic_vector(counter_size downto 0) := (others => '0'); --counter output

signal counter_set : std_logic; --sync reset to zero

signal result : std_logic; --debouncer result

begin

counter_set <= flipflops(0) xor flipflops(1); --determine when to start/reset counter

process(clk)

begin

if(clk'event and clk = '1') then

flipflops(0) <= button;

flipflops(1) <= flipflops(0);

if(counter_set = '1') then --reset counter because input is changing

counter_out <= (others => '0');

elsif(counter_out(counter_size) = '0') then --stable input time is not yet met

counter_out <= counter_out + 1;

else --stable input time is met

result <= not flipflops(1);

end if;

end if;

end process;

process(result)

begin

if(reset='0') then --when reset equal to '0' make count equal to 0.

counter <=(others => '0'); -- c ="0000"

elsif(result'event and result = '1') then

if(counter = "1111") then -- when count reaches its maximum(that is 15) reset it to 0

counter <="0000";

end if;

counter <= counter+'1'; --increment count at every positive edge of clk.

end if;

case counter is

when "0000"=>Digit<="1000000";-- 0

when "0001"=>Digit<="1111001";-- 1

when "0010"=>Digit<="0100100";-- 2

when "0011"=>Digit<="0110000";-- 3

when "0100"=>Digit<="0011001";-- 4

when "0101"=>Digit<="0010010";-- 5

when "0110"=>Digit<="0000010";-- 6

when "0111"=>Digit<="1111000";-- 7

when "1000"=>Digit<="0000000";-- 8

when "1001"=>Digit<="0010000";-- 9

when "1010"=>Digit<="0001000";-- A

when "1011"=>Digit<="0000011";-- b

when "1100"=>Digit<="1000110";-- C

when "1101"=>Digit<="0100001";-- d

when "1110"=>Digit<="0000110";-- E

when "1111"=>Digit<="0001110";-- F

when others=>Digit<="1111111";-- in other cases balnk

end case;

end process;

Digit_en<='0';

hex_count<=counter;

end;