shujuxianguanqi.txt

来自「包内共有六个源代码」· 文本 代码 · 共 29 行

library ieee;
use ieee.std_logic_1164.all;
entity shujuxiangguanqi is
  port(clk:in std_logic;
       a,b:in std_logic;
       count:out std_logic;
       q:buffer integer range 0 to 16);
end shujuxiangguanqi;
architecture jiegou of shujuxiangguanqi is
  begin
    process(clk)
      variable n:integer range 0 to 15;
        begin
         if clk'event and clk='1'then
                n:=n+1;
          if n=0 and (a xor b)='1'then
                q<=0;
           elsif n=0 and (a xor b)='0'then
                q<=1;
           elsif (a xor b)='0'then
                q<=q+1;
          end if;
         end if;
          if (q=16)then
             count<='1';
           else count<='0';
           end if;
    end process;
end jiegou;