-- =======================================================================
-- Author:  Antonio Esteves, GEC-DI-UM.
-- File:    ffd_ce.vhd
-- Date:    13 August 2000
--
-- D flip-flop with clock enable.
-- =======================================================================

library IEEE;
use     IEEE.std_logic_1164.all;
use     IEEE.std_logic_unsigned.all;

-- flip-flop with clock enable

entity ffd_ce is   
    port (
       data_in    : in    std_logic;
       clock      : in    std_logic;
       enable     : in    std_logic;
       data_out   : out   std_logic
       );
end ffd_ce ;

architecture rtl of ffd_ce  is
begin
   process (clock, enable)
   begin
      if (clock'event and clock='1') then
         if (enable='1')  then
            data_out <= data_in ;
         end if;
      end if;
   end process;
end rtl;