led.vhd

利用示波器的X和Y通道输出采样波形图形 注：显示两个周期。扫频频率100Hz

--**********************************************************
LIBRARY ieee;
USE ieee.std_logic_1164.ALL;
USE ieee.std_logic_unsigned.ALL;
--*********************************************************
ENTITY LED IS                                                                     --?????
     port( clk: in std_logic; 
		   n1,n2,n3,n4,n5,n6:in std_logic_vector(3 downto 0);
		   wei:out std_logic_vector(5 downto 0);
		   dan: out std_logic_vector(6 downto 0));
END LED;
--*********************************************************
ARCHITECTURE zx OF LED IS
	signal clk1:std_logic;
	--******************************************************************	
	function coding (num:std_logic_vector(3 downto 0)) return std_logic_vector is
			variable tmwei:std_logic_vector(6 downto 0);
		begin
			case num is 
				when "0000"=>tmwei:="1111110";
				when "0001"=>tmwei:="0110000";
				when "0010"=>tmwei:="1101101";	
				when "0011"=>tmwei:="1111001";
				when "0100"=>tmwei:="0110011";
				when "0101"=>tmwei:="1011011";
				when "0110"=>tmwei:="1011111";
				when "0111"=>tmwei:="1110000";
				when "1000"=>tmwei:="1111111";
				when "1001"=>tmwei:="1111011";
				when others=>tmwei:="0000000";
			end case ;
			return tmwei;
	end coding;
--************************************************************
	
begin 
	process(clk)
		variable com:integer range 0 to 10000;
	begin 
	    if( clk 'event and clk='1') then
			if(com=10000) then com:=0;clk1<=not clk1;
			else com:=com+1;
			end if;
		end if;
    end process;
	
	--*****************??????*****************************************
	process(clk1)
   		variable x: integer range 0 to 5;
    begin 
		if(clk1'event and clk1='1') then  
		    if(x=5) then x:=0;
		    else x:=x+1;
		    end if;    
     		case x is
       			when 0=>wei<="000001";dan<=coding(n1);
	   			when 1=>wei<="000010";dan<=coding(n2);
  				when 2=>wei<="000100";dan<=coding(n3);
            	when 3=>wei<="001000";dan<=coding(n4);
				when 4=>wei<="010000";dan<=coding(n5);
				when 5=>wei<="100000";dan<=coding(n6);
				when others=>wei<="000000";
			end case;
   		end if;
	end process;
			
END zx;