八人抢答器vhdl

抢答器是一个比较简单的电路，可以使用VHDL进行实现。以下是一个基本的八人抢答器的VHDL代码：

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity buzzer is
    Port ( buzzer : out std_logic);
end buzzer;

architecture Behavioral of buzzer is
begin
    process
    begin
        buzzer <= '1'; -- 声音开
        wait for 100ms; -- 持续100ms
        buzzer <= '0'; -- 声音关
        wait; -- 等待下一次触发
    end process;
end Behavioral;

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity button is
    Port ( btn : in std_logic);
end button;

architecture Behavioral of button is
begin
    -- do something when button is pressed
end Behavioral;

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity controller is
    Port ( clk : in std_logic;
           reset : in std_logic;
           buzzer_out : out std_logic;
           btn1 : in std_logic;
           btn2 : in std_logic;
           btn3 : in std_logic;
           btn4 : in std_logic;
           btn5 : in std_logic;
           btn6 : in std_logic;
           btn7 : in std_logic;
           btn8 : in std_logic);
end controller;

architecture Behavioral of controller is

    -- 状态定义
    type state_type is (idle, wait, buzz);
    signal state : state_type := idle;

    -- 定义计数器
    signal count : integer range 0 to 1000000 := 0;

    -- 定义抢答标志
    signal buzzer_flag : std_logic := '0';

begin

    -- 状态机
    process(clk, reset)
    begin
        if reset = '1' then
            state <= idle;
            count <= 0;
            buzzer_flag <= '0';
        elsif rising_edge(clk) then
            case state is
                when idle =>
                    if btn1 = '1' or btn2 = '1' or btn3 = '1' or btn4 = '1' or btn5 = '1' or btn6 = '1' or btn7 = '1' or btn8 = '1' then
                        state <= wait;
                        count <= 0;
                    end if;
                when wait =>
                    if count = 100000 then -- 等待1s
                        state <= buzz;
                        count <= 0;
                        buzzer_flag <= '1'; -- 抢答成功
                    else
                        count <= count + 1;
                    end if;
                when buzz =>
                    if count = 100000 then -- 持续1s
                        state <= idle;
                        count <= 0;
                        buzzer_flag <= '0'; -- 抢答结束
                    else
                        count <= count + 1;
                    end if;
            end case;
        end if;
    end process;

    -- 控制蜂鸣器
    buzzer : entity work.buzzer
        port map(buzzer_out);

    -- 控制按钮
    button1 : entity work.button
        port map(btn1);
    button2 : entity work.button
        port map(btn2);
    button3 : entity work.button
        port map(btn3);
    button4 : entity work.button
        port map(btn4);
    button5 : entity work.button
        port map(btn5);
    button6 : entity work.button
        port map(btn6);
    button7 : entity work.button
        port map(btn7);
    button8 : entity work.button
        port map(btn8);

end Behavioral;

这个代码实现了一个简单的八人抢答器，使用了状态机的思想。当有任意一个按钮被按下时，进入等待状态，等待1秒钟后开始响铃，并设置一个抢答标志。持续1秒钟后停止响铃，并清除抢答标志。在整个过程中，抢答器可以不断地接收按钮输入，但只有一次抢答成功。