用VHDL语言编写交通灯
时间: 2024-05-05 13:21:04 浏览: 11
以下是一个简单的交通灯的VHDL代码示例:
```
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity traffic_light is
port (
clk: in std_logic;
reset: in std_logic;
red_led: out std_logic;
yellow_led: out std_logic;
green_led: out std_logic
);
end traffic_light;
architecture Behavioral of traffic_light is
type state_type is (stop, ready, go, caution);
signal state: state_type;
signal timer: integer range 0 to 10000000 := 0; -- 时钟周期计数器
constant stop_time: integer := 10000000; -- 红灯时间
constant ready_time: integer := 5000000; -- 黄灯时间
constant go_time: integer := 10000000; -- 绿灯时间
begin
-- 状态转换逻辑
process (clk, reset)
begin
if reset = '1' then
state <= stop; -- 初始状态为红灯
timer <= 0;
elsif rising_edge(clk) then
case state is
when stop =>
if timer >= stop_time then
state <= ready;
timer <= 0;
else
timer <= timer + 1;
end if;
when ready =>
if timer >= ready_time then
state <= go;
timer <= 0;
else
timer <= timer + 1;
end if;
when go =>
if timer >= go_time then
state <= caution;
timer <= 0;
else
timer <= timer + 1;
end if;
when caution =>
if timer >= ready_time then
state <= stop;
timer <= 0;
else
timer <= timer + 1;
end if;
end case;
end if;
end process;
-- 灯的控制逻辑
process (state)
begin
case state is
when stop =>
red_led <= '1';
yellow_led <= '0';
green_led <= '0';
when ready =>
red_led <= '1';
yellow_led <= '1';
green_led <= '0';
when go =>
red_led <= '0';
yellow_led <= '0';
green_led <= '1';
when caution =>
red_led <= '0';
yellow_led <= '1';
green_led <= '0';
end case;
end process;
end Behavioral;
```
该代码使用状态机实现了一个基本的交通灯控制器。在每个状态下,根据计时值控制红、黄、绿三个灯的亮灭。在状态转换时,计时器被重置并切换到下一个状态。可以根据需要修改计时器的值和状态转换条件来实现不同的交通灯控制逻辑。