--設計一個6層電梯控制器。電梯控制器是按照乘客的要求自動上、下的裝置。 
--1、每層電梯入口處設置上下請求開關，電梯內設有顧客到達層次的停站請求開關。 
--2、設有電梯所處位置指示裝置以及電梯運行模式（上升或者下降）指示裝置。 
--3、電梯每秒升降一層樓。 
--4、電梯到達有停站請求的樓層，經過1秒電梯門打開，開門4秒后，電梯門關閉（開門指示燈滅），電梯繼續運行，直至執行完最后一個請求信號后停留在當前層。 
--5、電梯能記憶電梯內外所有請求信號，并按照電梯運行規則按順序響應，每個請求信號保留至有電梯響應后消除。 
--6、電梯運行規則：當電梯上升時，只響應比電梯所在位置高的上樓請求信號，由下而上逐個執行，直到最后一個上樓請求執行完畢；
--如果高層有下樓請求，則直接升到下樓請求的最高樓層，然后進入下降模式。當電梯處于下降模式時與上升正好相反

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;

entity elerun is
port (	
	clk:	in std_logic;		--電梯時鐘
	alarm:   in std_logic;
	reset:		in std_logic;		--異步置位按鍵
	fuplight:	in std_logic_vector (6 downto 1);--電梯外部上升請求指示燈
	fdnlight:	in std_logic_vector (6 downto 1);--電梯外部下降請求指示燈
	stlight:	in std_logic_vector (6 downto 1);--電梯內部各層請求指示燈
	position:	out integer range 1 to 6;		--電梯位置指示
	doorlight:	out std_logic;			--電梯門開關指示燈
	clearup:out std_logic;--用于清除上升請求指示燈的信號
	cleardn:out std_logic;--用于清除下降請求指示燈的信號
	yanshi:in std_logic;
	tiqian: in std_logic;
	udsig:		buffer std_logic_vector(7 downto 0)	--電梯升降指示			
);
end elerun;
	
architecture sixflift of elerun is
	type lift_state is
	(stopon1,dooropen,doorclose,doorwait1,doorwait2,doorwait3,doorwait4,doorwait5,doorwait6,up,down,stop);
	signal mylift: lift_state;
	signal pos: integer range 6 downto 1;
	signal udflag : std_logic;
	signal posreg : integer range 1 to 6;
	signal one:		std_logic_vector (6 downto 1);
begin
	
process(reset,clk)		--控制電梯狀態的進程
begin 
	if (reset = '1' or alarm = '1') then
		 mylift <= stopon1;	
		 clearup <= '1';
		 cleardn <= '1';		
	else
		if (clk 'event and clk = '1') then
		case mylift is
			when stopon1 => 
				doorlight <= '0';	
				posreg <= 1;					
				mylift <= doorwait1;								
				clearup <= '0';
				cleardn <= '0';
				udsig <= "00000010";						
			when doorwait1 => 
				if tiqian = '1' then
					mylift <= doorclose;
				elsif yanshi = '1' then
					mylift <= doorwait1;
				else
					mylift <= doorwait2;
				end if;				
				clearup <= '0';
				cleardn <= '0';							
			when doorwait2 => 
				if tiqian = '1' then
				mylift <= doorclose;
				elsif yanshi = '1' then
					mylift <= doorwait1;
				else
					mylift <= doorwait3;
				end if;				
				clearup <= '0';
				cleardn <= '0';							
			when doorwait3 => 
				if tiqian = '1' then
					mylift <= doorclose;
				elsif yanshi = '1' then
					mylift <= doorwait1;
				else
					mylift <= doorwait4;
				end if;
				clearup <= '0';
				cleardn <= '0';							
			when doorwait4 => 
				if tiqian = '1' then
					mylift <= doorclose;
				elsif yanshi = '1' then
					mylift <= doorwait1;
				else
					mylift <= doorwait5;
				end if;				
				clearup <= '0';
				cleardn <= '0';							
			when doorwait5 => 
				if tiqian = '1' then
					mylift <= doorclose;
				elsif yanshi = '1' then
					mylift <= doorwait1;
				else
					mylift <= doorwait6;
				end if;				
				clearup <= '0';
				cleardn <= '0';
							
			when doorwait6 => 
				mylift <= doorclose;                
				cleardn <= (not udflag); 
				clearup <= udflag;
			when doorclose => 
				doorlight <= '0';					
				clearup <= '0';
				cleardn <= '0';				
				if posreg = 6 then
					if (stlight = "000000" and fuplight = "000000" and fdnlight = "000000") then							
						mylift <= doorclose;							
						udsig <= "00000010";
					elsif stlight > "000000" or fdnlight > "000000" or fuplight > "000000" then
						mylift <= down;							
						udsig<="01111010";
						udflag <= '1';
					end if;
				elsif posreg = 1 then
					if (stlight = "000000" and fuplight = "000000" and fdnlight = "000000") then							
						mylift <= doorclose;							
						udsig <= "00000010";
					elsif stlight > "000000" or fdnlight > "000000" or fuplight > "000000" then
						 mylift <= up;
						udsig<="01111100";
						udflag <= '0';
					end if;	
				else
					if (stlight = "000000" and fuplight = "000000" and fdnlight = "000000") then
						mylift <= doorclose;
						udsig <= "00000010";						
					elsif stlight >= (one + one)   or  fuplight >= (one + one) or fdnlight >= (one + one) then
						mylift <= up;
						udsig<="01111100";
						udflag <= '0';
					elsif (stlight + stlight) <= one  or  (fuplight + fuplight)  <= one  or (fdnlight + fdnlight) <= one then 							
						mylift <= down;
						udsig<="01111010";
						udflag <= '1';
					else 
						mylift <= doorclose;
					end if;		
				end if;										
			when up =>			
				clearup <= '0';
				cleardn <= '0';				
				if posreg < 6 and (stlight(posreg) = '1' or fuplight(posreg) = '1'  or (stlight = "000000" and fdnlight(posreg) = '1'))
					then mylift <= stop;
					if  (stlight = "000000" and fdnlight(posreg) = '1' and fuplight = "000000") then
						udflag <= '1';
					end if;						
				elsif posreg = 6 and (stlight(posreg) = '1' or fuplight(posreg) = '1' or ( fuplight = "000000" and fdnlight(posreg) = '1'))				
					then mylift <= stop;					
						 
				elsif posreg = 6 and ( fdnlight > "000000" or fuplight > "000000") then
					mylift <= stop;				
				else
					mylift <= up;					
					udsig<="01111100";	
					udflag <= '0';					 
					if posreg<6 then
						posreg <= (posreg+1);
					end if;				
				end if;
			when down =>			
				clearup <= '0';
				cleardn <= '0';			   
				if posreg > 1 and (stlight(posreg) = '1' or fdnlight(posreg) = '1' or ( stlight = "000000" and fuplight(posreg) = '1' ))
					then mylift <= stop;
					if (stlight = "000000" and fuplight(posreg) = '1' and fdnlight = "000000") then
						udflag <= '0';
					end if;
				elsif posreg = 1 and (stlight(posreg) = '1' or fdnlight(posreg) = '1' or  ( fdnlight = "000000" and fuplight(posreg) = '1'))			
					then mylift <= stop;	
				elsif posreg = 1 and ( fdnlight > "000000" or fuplight > "000000") then
					mylift <= stop;
				else 
					mylift <= down;
					udsig<="01111010";
					udflag <= '1';					
					if posreg>1 then	
						posreg <= (posreg-1);
					end if;					
				end if;
			when stop => 
				mylift <= dooropen;						
				clearup <= '0';
				cleardn <= '0';	
			when dooropen => 
				doorlight <= '1';			    
				clearup <= '0';
				cleardn <= '0';						
				mylift <= doorwait1;
		when others =>
				mylift <= doorwait1;	
				clearup <= '0';
				cleardn <= '0';						
		end case;
		end if;	
  end if;	
end process ;
	position <= posreg;
process(clk,posreg)
begin
	if clk 'event and clk = '1' then
		case posreg is
		when 1 => one <= "000001";
		when 2 => one <= "000010";
		when 3 => one <= "000100"; 
		when 4 => one <= "001000"; 
		when 5 => one <= "010000"; 
		when 6 => one <= "100000"; 
		end case;
	end if;
end process ;	
end ;