bell.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 bell is 
 port(bell1,bell2:in std_logic;
      bellout:out std_logic);
end entity;
architecture dataflow of bell is
begin 
bellout<=bell1 or bell2;
end dataflow;