key.vhd

采用VHDL语言编写的万年历程序

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity key is
    Port (sysclk,key1,reset,add,sub: in std_logic;
	      led1,led10,led100,led1000,clock3200: out std_logic;
			N:out integer range 1023 downto 0);
end key;

architecture Behavioral of key is
type state is (st1,st2);
signal current :state;
type state_1 is (s1,s2,s3);
signal current_1 :state_1;
signal clk3200:std_logic;
signal step1,step10,step100,step1000 :std_logic;
begin


process(sysclk,reset)
 variable count2: integer;
		variable clk0: std_logic;
		begin
		   if  reset='0' then
			 count2:=0;
			 clk0:='0';
			 elsif sysclk'event and sysclk='1' then
			  count2:=count2+1;
			  if count2=1600  then
			  clk0:='1';
			  elsif count2=3200 then
			    count2:=0;
				 clk0:='0';
		     --end if;
			 end if;
			end if;
		clock3200<=clk0;
		clk3200<=clk0;
end process;




process(key1,clk3200)
variable cnt :integer range 4 downto 0 ;
begin
if reset='0' then
cnt:=0;
current<=st1;
step1<='1';step10<='1';step100<='0';step1000<='1';
elsif rising_edge(clk3200) then

 case current is
   when st1 =>if key1='0' then current<=st2;
	            end if;  
   when st2 =>if key1='1' then 
	           cnt:=cnt+1;
				  case cnt is
				  when 1=>step1<='0';step10<='1';step100<='1';step1000<='1';current<=st1;
              when 2=>step1<='1';step10<='0';step100<='1';step1000<='1';current<=st1;
              when 3=>step1<='1';step10<='1';step100<='0';step1000<='1';current<=st1;
				  when 4=>step1<='1';step10<='1';step100<='1';step1000<='0';cnt:=0;current<=st1;
				  when others =>null;
				   
				  end case;
				end if;
   when others=>null;
 end case;
 end if;

end process;




process(reset,clk3200)
 variable count2,count3,count5: integer range 1023 downto 0 ;
		variable clk0: std_logic;
		begin
		if  reset='0' then
			 N<=100;
			 clk0:='0';
			 count3:=100;
			 current_1<=s1;

		   elsif clk3200'event and clk3200='1' then
       case current_1 is
		  when s1 =>if add='0' then current_1<=s2;
		             elsif sub='0' then current_1<=s3;
	                end if;  
        when s2 =>if add='1' then
		   if step1='0' then count3:=count3+1;current_1<=s1;
			elsif step10='0' then count3:=count3+10;current_1<=s1;
			elsif step100='0' then count3:=count3+100;current_1<=s1;
			elsif step1000='0' then count3:=count3+1000;current_1<=s1;
			end if;
			end if;
		  when s3 =>if sub='1' then
			if step1='0' then count3:=count3-1;current_1<=s1;
			elsif step10='0' then count3:=count3-10;current_1<=s1;
			elsif step100='0' then count3:=count3-100;current_1<=s1;
			elsif step1000='0' then count3:=count3-1000;current_1<=s1;
			end if;
			
			
			end if;
			when others =>null;
			end case;
			end if;
   
         N<=count3;
	   end process ;
led1<=step1;led10<=step10;led100<=step100;led1000<=step1000;

end Behavioral;