fredevider.vhd

基于VHDL实现的十字路口交通灯功能

library ieee;
use ieee.std_logic_1164.all;

entity fredevider is
port
(clkin:in std_logic;
 clkout:out std_logic);
end;

architecture b_fredevider of fredevider is
constant n:integer:=3;
signal counter:integer range 0 to n;
signal clk:std_logic;
 begin
  process(clkin)
   begin
    if rising_edge(clkin) then
      if counter=n then
        counter<=0;
        clk<=not clk;
      else
        counter<=counter+1;
       end if;
     end if;
   end process;
 clkout<=clk;
end;