deng.txt

多功能秒表：可以顺计时和倒计时的秒表,用三位数码管显示。

library ieee;
use ieee.std_logic_1164.all;
entity deng is
  port(change,control:in std_logic;
       light:out std_logic_vector(2 downto 0));
end entity;
architecture behav of deng is
begin
 process (control,change)
  begin
   if control='0' then light<="001";
    elsif change='0' then light<="010";
     else light<="100";
   end if;
 end process;
end behav;