conclk.vhd

用VHDL实现的DDS

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity conclk is port
(
   clk : in std_logic;
   clr :in std_logic;
   s   :buffer std_logic_vector(2 downto 0)
);
end conclk;
architecture behave of conclk is
  begin 
   process(clk,clr)
  begin
     if(clr='1')then
      s<="000";
     elsif(clk'event and clk='1')then
       if(s="110")then
          s<="000";
       else s<=s+1;
      end if;
end if;
     end process;
end behave;