我正在尝试在交通信号灯控制器上实现“紧急”功能。
此紧急信号是std_logic输入，由按钮（使用ucf文件）触发。
该信号的作用基本上是每当按下按钮时，控制器就会检测到两条道路（北至南或西至东）中的哪一条处于红色，并立即将其切换为橙色（另一条，当然会变成红色）以让紧急车辆通过（例如，一辆救护车）。
我试图对开关进行声控，然后将声控信号馈入上升沿检测器。它没有用：按下紧急按钮会使两条道路（NS和WE）的红色和黄色灯同时亮起，只是一场灾难，我用来配置每盏灯亮起时间的计数器也被打乱了。在恢复正常之前花了相当长的一段时间。
到目前为止，这是我的代码：
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use ieee.std_logic_unsigned.all;
use ieee.numeric_std.all;
entity TLC is
Port (
Clck : in STD_LOGIC;
Reset: in STD_LOGIC;
emergency:in std_logic;
Trafficlights: out STD_LOGIC_Vector (5 downto 0) --trafficlights (5 downto 3) for the NS road and (2 downto 0) for the WE road.
);
end TLC;
architecture Behavioral of TLC is
-------------for debouncing
constant COUNT_MAX : integer := 20;
constant BTN_ACTIVE : std_logic := '1';
signal count1 : integer := 0;
type state_type1 is (idle,wait_time);
signal state1 : state_type1 := idle;
signal emergency_debounced:std_logic;
-----------------------------------------
type state_type is (NRWG, NRWY, NGWR, NYWR); --NRWG: North-South on red and West-East on green and so on.
signal one_second_counter: STD_LOGIC_vector(25 downto 0):="00000000000000000000000000";
signal one_second_enable: std_logic;
signal state: state_type:=NRWG;
signal count : std_logic_vector (3 downto 0);
constant sec8 : std_logic_vector ( 3 downto 0) := "1000";
constant sec3 : std_logic_vector (3 downto 0 ) := "0011";
constant sec11: std_logic_vector (3 downto 0 ) := "1011";
--edge detector signals
signal emergencya, emergencyb, emergencyc: std_logic;
----------
begin
controller: process (Clck,reset,emergencyc)
begin
if emergencyc='1' then
if state=NRWG or state=NRWY then ----if NS is on red then switch it to yellow.
state<=NYWR;
count<=x"0";
else
if state=NGWR or state=NYWR then ----if WE is on red then switch it to yellow.
state<=NRWY;
count<=x"0";
end if;
end if;
elsif reset ='1' then
state<=NRWG;
count<=X"0";
else
if rising_edge(clck) then
if one_second_enable='1' then
case state is
when NRWG =>
if count < sec8 then
state <= NRWG;
count <= count + 1;
else
state <= NRWY;
count <= X"0";
end if;
when NRWY =>
if count < sec3 then
state <= NRWY;
count <= count + 1;
else
state <= NGWR;
count <= X"0";
end if;
when NGWR =>
if count < sec11 then
state <= NGWR;
count <= count + 1;
else
state <= NYWR;
count <= X"0";
end if;
when NYWR =>
if count < sec3 then
state <= NYWR;
count <= count + 1;
else
state <=NRWG;
count <= X"0";
end if;
when others =>
state <= NRWG;
end case;
end if;
end if;
end if;
end process;
-----------decode state
OUTPUT_DECODE: process (state)
begin
case state is
when NRWG => Trafficlights <= "100001";
when NRWY => Trafficlights <= "100010";
when NGWR => Trafficlights <= "001100";
when NYWR => Trafficlights <= "010100";
when others => Trafficlights <= "100001";
end case;
end process;
--------------------------------
--------------Slow_Clock-------------
slow_clock:process(clck) begin
if(rising_edge(clck)) then
if(one_second_counter="10111110101111000010000000") then
one_second_counter <="00000000000000000000000000";
else
one_second_counter <= one_second_counter +1;
end if;
end if;
end process;
one_second_enable <= '1' when one_second_counter="10111110101111000010000000" else '0';
---------------------------------------------------
-----------------for debouncing---------------
debounce_emergency:process(clck)
begin
if(rising_edge(Clck)) then
case (state1) is
when idle =>
if(emergency = BTN_ACTIVE) then
state1 <= wait_time;
else
state1 <= idle;
end if;
emergency_debounced <= '0';
when wait_time =>
if(count1 = COUNT_MAX) then
count1 <= 0;
if(emergency = BTN_ACTIVE) then
emergency_debounced <= '1';
end if;
state1 <= idle;
else
count1 <= count1 + 1;
end if;
end case;
end if;
end process;
------------------------------------------------------------
---------edge_detector--------
edge_detection:process (clck)
begin
if(rising_edge(clck)) then
emergencya <= emergency_debounced;
emergencyb <= emergencya;
end if;
end process ;
emergencyc <= not emergencyb and emergencya;
---------------------------------
end Behavioral;
关于紧急功能为何无法正常运行的任何想法？
答案 0 :(得分：1)
您的debounce_emergency:process在许多方面都是错误的。我建议您模拟设计以查看它。如果按下emergency按钮40个时钟周期会怎样？
此外，controller: process中的if emergencyc='1' ...部分必须位于if rising_edge(clck)内，否则将触发状态信号的多个变化。