bel.vhd

1、正常的计时功能：即具有二十四小时计时功能 2、正常的显示功能 3、正常的调时功能 4、闹钟定时功能 5、整点报时功能

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity bel is
 port(ms1,ss1:in std_logic_vector(7 downto 4);
      ms2,ss2:in std_logic_vector(3 downto 0);
      bell:   out std_logic;
      cpt,f512,f1024:in std_logic);
end bel;
architecture belx of bel is
 signal  m0,n0: std_logic;
  begin 
   process(m0,n0,ms1,ms2,ss1,ss2)
    begin
    if cpt='1' then
        m0<=f512;
        n0<='0';
    elsif(ms1=5 and ms2=9 and ss1=5 and cpt='0')then
      if(ss2=1 or ss2=3 or ss2=5 or ss2=7)then
        m0<='0';
        n0<=f512;
      elsif ss2=9 then
        m0<='0';
        n0<=f1024;
      end if;
    end if;
  end process;
 bell<=m0 or n0;
end belx;