lcok.vhd

数字密码锁:S0是复位状态：密码为00000001

library ieee;
use ieee.std_logic_1164.all;
entity lock is
	port(
	key,rst,change: in std_logic;
	code:in std_logic_vector(7 downto 0);
	led1,led2: out std_logic
		);
end lock;

architecture lock of lock is
type state_type is(s0,s1,s2);
begin
	process(rst,key)
	variable state: state_type:=s0;
	variable temp:std_logic_vector(7 downto 0):="00000001";
	begin
	
	if rst = '0' then
	state := s0;
	temp:="00000001";
	led1<='1';
	led2<='0';
	

	elsif(key'event and key = '1' )then
	case state is
		when s0 => if temp=code then
		state:=s1;
		else
		state:=s0;
		end if;
		
		when s1 => 
		if change = '1' then state:=s2;
		end if;
		if change = '0' then state:=s0;
		end if;
		
		when s2 =>
		temp:=code;
		state:=s0;
		
	end case;
	end if;
	if(state = s0)then
	led1<='1';
	led2<='0';
	elsif(state = s1)then
	led1<='0';
	led2<='1';
	else
	led1<='1';
	led2<='1';
	end if;
	
	end process;
end lock;