counter9.vhd

VHDL实现交通灯

LIBRARY  IEEE;
USE  IEEE.STD_LOGIC_1164.ALL;
USE  IEEE.STD_LOGIC_UNSIGNED.ALL;

Entity counter9 is
port(clkin:in std_logic;
     qout:out std_logic_vector(6 downto 0);
     qou:out std_logic_vector(6 downto 0)
);
end counter9;

architecture counter9 of counter9 is
signal bcd:std_logic_vector(3 downto 0);
signal out1:std_logic_vector(6 downto 0);
signal bc:std_logic_vector(3 downto 0);
signal ou:std_logic_vector(6 downto 0);
begin
process(clkin)
begin
 if(clkin'event and clkin='1') then
   if(bcd="1010")then 
   bcd<="0000";
   bc<=bc+'1';
   if bc="0110" then 
   bc<="0000";
   end if;
    else bcd<=bcd+'1';
  end if;
   case bcd is
     when "0000"=>out1<="1111110";
     when "0001"=>out1<="0110000";
     when "0010"=>out1<="1101101";
     when "0011"=>out1<="1111001";
     when "0100"=>out1<="0110011";
     when "0101"=>out1<="1011011";
     when "0110"=>out1<="1011111";
     when "0111"=>out1<="1110000";
     when "1000"=>out1<="1111111";
     when "1001"=>out1<="1111011";
      when others=>out1<="1111110";
   end case;
   case bc is
     when "0000"=>ou<="1111110";
     when "0001"=>ou<="0110000";
     when "0010"=>ou<="1101101";
     when "0011"=>ou<="1111001";
     when "0100"=>ou<="0110011";
     when "0101"=>ou<="1011011";
     when others=>ou<="1111110";
   end case;
  end if;
  end process;
 qout<=out1;
 qou<=ou;
end counter9;