traffic.vhd

利用vhdl编写的模拟交通灯的程序

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity traffic is	
    Port (Clock,Reset:in std_logic;
          Strait_A_Out,Block_A_Out,Turn_A_Out,Strait_B_Out,Block_B_Out,Turn_B_Out:out std_logic;
          Count_Down_LCD:out std_logic_vector(6 downto 0);
          Road_sign: out std_logic_vector(13 downto 0);
          Ctr:out std_logic
          );
end entity;

architecture traffic of traffic is
signal Clock_4Hz,LCD:std_logic;
signal Count_4Hz:std_logic_vector(4 downto 0);
signal Count_1Hz:std_logic_vector(1 downto 0);
signal Clock_1Hz:std_logic;
signal Count_Down:std_logic_vector(2 downto 0);
--signal Count_Down_LCD:std_logic_vector(6 downto 0);
signal q:std_logic_vector(13 downto 0);
signal State:std_logic_vector(1 downto 0);
signal Count:std_logic_vector(2 downto 0);
signal Strait_A,Block_A,Turn_A,Strait_B,Block_B,Turn_B,Blink:std_logic;
--//wire [13:0] Road_sign
constant  Strait_Block :std_logic_vector:="00";
constant  Block_Turn :std_logic_vector:="01";
constant  Turn_Block :std_logic_vector:="10";
constant  Block_Strait :std_logic_vector:="11";

begin
  Ctr<='1';
  Strait_A_Out<=Strait_A and (Clock_4Hz or Blink);
  Strait_B_Out<=Strait_B and (Clock_4Hz or Blink);
  Block_A_Out<=Block_A and (Clock_4Hz or Blink);
  Block_B_Out<=Block_B and (Clock_4Hz or Blink);
  Turn_A_Out<=Turn_A and (Clock_4Hz or Blink);
  Turn_B_Out<=Turn_B and (Clock_4Hz or Blink);

  Road_sign(13 downto 7) <= q(13 downto 7);
  Road_sign(6 downto 0) <= ((not q(6))and (Clock_4Hz or Blink))&((not q(5))and (Clock_4Hz or Blink))&((not q(4))and (Clock_4Hz or Blink))&
                    ((not q(3))and (Clock_4Hz or Blink))&((not q(2))and (Clock_4Hz or Blink))&((not q(1))and (Clock_4Hz or Blink))&
                    ((not q(0))and (Clock_4Hz or Blink));
 

--//*************  Generate 4Hz Clock Signal from 1kHz Clock Signal  **********
  process(Clock)
  begin
	if Clock'event and Clock='1' then
	   Count_4Hz <= Count_4Hz-1;
	   if Count_4Hz="0000" then
		  Clock_4Hz <=  not Clock_4Hz;--Generate 4Hz clock signal
	   end if;
	end if;
  end process;	

--//*************  Generate 1Hz Clock Signal from 4Hz Clock Signal  ***********	
  process (Clock_4Hz)
  begin
    if Clock_4Hz'event and Clock_4Hz='1' then
       Count_1Hz <= Count_1Hz-1;
	   if Count_1Hz="00" then
	      Clock_1Hz <= not Clock_1Hz;	--//Generate 1Hz clock signal
	   end if;
	end if;
  end process;	
		

--//****************************  Main Program  *******************************
  process (Clock_1Hz)
  begin
    if Clock_1Hz'event and Clock_1Hz='1' then
       if Reset='1' then
		  State<=Strait_Block;
		  Count_Down<="000";
		  Strait_A<='1'; Block_A<='1'; Turn_A<='1';
		  Strait_B<='1'; Block_B<='1'; Turn_B<='1';
		  Count_Down_LCD<="1111111";
		  Blink<='1';
			
	   else
		  Count_Down<=Count_Down-1;
		  if State=Strait_Block then
			 Strait_A<='1'; Block_A<='0'; Turn_A<='0';
			 Strait_B<='0'; Block_B<='1'; Turn_B<='0';
			 if Count_Down="000" then
			    State<=Block_Turn;
			 end if;
		  elsif State=Block_Turn then
			 Strait_A<='0'; Block_A<='1'; Turn_A<='0';
			 Strait_B<='0'; Block_B<='0'; Turn_B<='1';
			 if Count_Down="000" then
			    State<=Turn_Block;	
			 end if;
		  elsif State=Turn_Block then
			 Strait_A<='0'; Block_A<='0'; Turn_A<='1';
			 Strait_B<='0'; Block_B<='1'; Turn_B<='0';
			 if Count_Down="000" then
			    State<=Block_Strait;
			 end if;
		  elsif State=Block_Strait then
			 Strait_A<='0'; Block_A<='1'; Turn_A<='0';
			 Strait_B<='1'; Block_B<='0'; Turn_B<='0';
			 if Count_Down="000" then
			    State<=Strait_Block;
			 end if;
		  end if;	
		  case Count_Down is
			 when "000"=>Count_Down_LCD<="0000110";--	//1
			 when "001"=>Count_Down_LCD<="1011011";--	//2
			 when "010"=>Count_Down_LCD<="1001111";	--//3
			 when "011"=>Count_Down_LCD<="1100110";--	//4
			 when "100"=>Count_Down_LCD<="1101101";-- //5
			 when "101"=>Count_Down_LCD<="1111101";--	//6
			 when "110"=>Count_Down_LCD<="0000111";	--//7
			 when "111"=>Count_Down_LCD<="1111111";	--//8
		  end case ;  
		  if Count_Down>=3 then
		     Blink<='1';
		  else 
		     Blink<='0';
		  end if;
	   end if;
	 end if;
   end process;

process (Clock)
variable a:std_logic_vector(2 downto 0);
begin
  if Clock'event and Clock='1' then
     if Reset='1' then
		q<="00000000000000";
	 else
	    if Count="111" then
		   Count<="000";
	    else
		   Count<=Count+1;	
		end if;
		a:=Strait_A&Block_A&Turn_A;
		case a is
		  when "100"=>case Count is
		                when "000"=>q<="10000001111111";
						when "001"=>q<="01000001111111";
						when "010"=>q<="00100001011111";
						when "011"=>q<="00010000000000";
						when "100"=>q<="00001001011111";
						when "101"=>q<="00000101111111";
						when "110"=>q<="00000011111111";
						when others=> null;						
					  end case;
		  when "010"=>case Count is
		                when "000"=>q<="10000000111110";
						when "001"=>q<="01000001011101";
						when "010"=>q<="00100001101011";
						when "011"=>q<="00010001110111";
						when "100"=>q<="00001001101011";
						when "101"=>q<="00000101011101";
						when "110"=>q<="00000010111110";
						when others=> null;						
					  end case;
          when "001"=>case Count is
		                when "000"=>q<="10000001111111";
						when "001"=>q<="01000001111111";
						when "010"=>q<="00100001110000";
						when "011"=>q<="00010001101111";
						when "100"=>q<="00001001101111";
						when "101"=>q<="00000101000111";
						when "110"=>q<="00000011101111";
						when others=> null;						
					  end case;	
		  when others=> null;						
		end case;
	  end if;
	end if;
  end process;	
end traffic;