在Quartus中vhdl实现电子密码锁

实现电子密码锁的VHDL代码如下：

library ieee;
use ieee.std_logic_1164.all;

entity password_lock is
    port (
        reset : in std_logic;
        clk   : in std_logic;
        input : in std_logic_vector(3 downto 0);
        valid : in std_logic;
        open  : out std_logic
    );
end entity password_lock;

architecture Behavioral of password_lock is

    type state_type is (idle, inputting, checking, unlocked);
    signal state : state_type := idle;

    signal password : std_logic_vector(3 downto 0) := "0000";
    signal count    : integer range 0 to 3 := 0;

begin

    process (reset, clk)
    begin
        if reset = '1' then
            state <= idle;
            password <= "0000";
            count <= 0;
            open <= '0';
        elsif rising_edge(clk) then
            case state is
                when idle =>
                    if valid = '1' then
                        state <= inputting;
                        password <= input;
                        count <= 1;
                    end if;
                when inputting =>
                    if valid = '1' then
                        password(count) <= input;
                        count <= count + 1;
                        if count = 3 then
                            state <= checking;
                        end if;
                    end if;
                when checking =>
                    if password = input then
                        state <= unlocked;
                        open <= '1';
                    else
                        state <= idle;
                        password <= "0000";
                        count <= 0;
                    end if;
                when unlocked =>
                    if valid = '1' then
                        state <= idle;
                        password <= "0000";
                        count <= 0;
                        open <= '0';
                    end if;
            end case;
        end if;
    end process;

end architecture Behavioral;

在这个代码中，我们定义了一个状态机来控制密码锁的逻辑。初始状态为`idle`，当用户输入有效的四位密码时，状态转换为`inputting`，同时将输入的密码存储在`password`信号中，并将`count`计数器初始化为1。在`inputting`状态下，如果用户继续输入有效的密码，则将其存储在`password`信号对应的位置，并将`count`计数器加1。当`count`计数器达到3时，状态转换为`checking`。在`checking`状态下，如果输入的密码与存储的密码相同，则状态转换为`unlocked`，同时将`open`信号设置为1以表示门被打开。如果输入的密码错误，则状态转换回`idle`，并将`password`信号和`count`计数器重新初始化。在`unlocked`状态下，如果用户再次输入有效的密码，则状态转换回`idle`，并将`password`信号和`count`计数器重新初始化，同时将`open`信号设置为0以表示门已关闭。