wan_m32.vhd

来自「此为一用VHDL编写的硬件游戏程序」· VHDL 代码 · 共 38 行

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
entity wan_m32 is
port(clk :in std_logic;
     areset :in std_logic;
     en     :in std_logic;
     cout   :out std_logic;
     q       :buffer std_logic_vector(4 downto 0));
end wan_m32;
architecture behave of wan_m32 is
begin
   process(clk,areset)
   begin
      if(areset='1')then
         q<=(others=>'0');
       elsif(rising_edge(clk))then
          if(en='1')then
            if(q="11110")then
               cout<='1';
               q<="11111";
            elsif(q="11111")then
             cout<='0';
             q<="00000";
            else
              cout<='0';
              q<=q+1;
            end if;
          else
            q<=q;
            cout<='0';
          end if;
     end if;
end process;
end behave;