and1.vhd

来自「数字钟的设计,实现正点报时的系统!.......」· VHDL 代码 · 共 28 行

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity AND1 is port 
   (HZSEL,CR:  in std_logic;
    AD6,AD5,AD4:  out std_logic);
end;
architecture ARC_AND1 of AND1 is
   signal  dou:  std_logic_vector(2 downto 0);
   begin
      AD6<=dou(2);
      AD5<=dou(1);
      AD4<=dou(0);
process(HZSEL,CR)
   begin
   if(CR='0')then
      dou<="000";
   elsif(HZSEL'event and HZSEL='1')then
           if(dou="111")then
               dou<="000";
           else
               dou<=dou+1;
           end if;
        end if;
   end process;
end ARC_AND1;