cnt10.vhd

在 Quartus II 7.1平台下

library ieee;          --十进制
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity cnt10 is
       port(clk :in std_logic;
            ena :in std_logic;
            clr :in std_logic;
              cq :out std_logic_vector(3 downto 0);
            outy :out std_logic);
end;
architecture art of cnt10 is
   signal cqi :std_logic_vector(3 downto 0);
begin
process (clk,clr,ena) is
begin
     if clr = '1' then cqi <="0000";
     elsif clk'event and clk='1' then
          if ena ='1' then 
             if cqi="1001" then cqi<="0000";
             else cqi <= cqi+1;
             end if;
          end if;
     end if;
end process;
process(cqi)
begin 
   if cqi="0000" then outy<='1';
   else outy<='0';
   end if;
end process;
cq <= cqi;
end;