library IEEE;
use IEEE.std_logic_1164.all;

entity password_get is
	port(
		clk			:	in	std_logic;
		key_inp 	:	in	std_logic_vector(1 downto 0);	--input (password) from keypad
		clear		:	in	std_logic;
		pass_out	:	out std_logic_vector(7 downto 0)
		);
end password_get;

architecture behaviour of password_get is

signal pass_reg		:	std_logic_vector(7 downto 0);
signal got_input	:	std_logic_vector(2 downto 0);
	--000 no input
	--001 first character
	--010 second character
	--011 third character
	--100 fourth char
signal obtain		: 	std_logic;
signal reset		:	std_logic;

begin

	process(clk)
	begin
	if clk'EVENT and clk='1' then

		if got_input ="000" or got_input ="001" or got_input ="010" or got_input ="011" or got_input ="100" then
			reset<='0';
		else
			reset<='1';
		end if;


		if reset='1' or clear='1' then

			got_input <= "000";
			pass_reg<="00000000";
			obtain<='0';		
			reset<='0';

		--get first char	
		elsif key_inp /= "00" and got_input="000" and obtain='0' then

			got_input<="001";
			pass_reg(1 downto 0)<=key_inp;
			obtain<='1';

		--get sencond char
		elsif key_inp/="00" and got_input="001" and obtain='0' then

			got_input<="010";
			pass_reg(3 downto 2)<=key_inp;
			obtain<='1';

		--get third char
		elsif key_inp/="00" and got_input="010" and obtain='0' then

			got_input<="011";
			pass_reg(5 downto 4)<=key_inp;
			obtain<='1';

		--get fourth char
		elsif key_inp/="00" and got_input="011" and obtain='0' then

			got_input<="100";
			pass_reg(7 downto 6)<=key_inp;
			obtain<='1';


		--go back to initial state
		elsif key_inp="00" and got_input="100" then
			got_input<="000";

		end if;

		if key_inp="00" then
			obtain<='0';
		end if;
		pass_out<=pass_reg;
	end if;

	end process;


end behaviour;




library IEEE;
use IEEE.std_logic_1164.all;

package password_get_package is
	component password_get 
		port(
			clk			:	in	std_logic;
			key_inp 	:	in	std_logic_vector(1 downto 0);	--input (password) from keypad
			clear 		: 	in	std_logic;
			pass_out	:	out std_logic_vector(7 downto 0)
			);
	end component;
end password_get_package;