judgedate.vhd

用VHDL实现的DDS

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity judgedate is
  port(
     cindate :in std_logic_vector(8 downto 0);
     coutdate : out std_logic_vector(7 downto 0)
);
end judgedate;
architecture behave of judgedate is
  begin 
process(cindate)
   begin
   if(cindate(8)='1') then
      coutdate<=not cindate(7 downto 0);
   else
     coutdate<=cindate(7 downto 0);
  end if;
end process;
end behave;