extlatch.vhd

VHDL版的C8051核(C8051).evatronix公司的IP核

--*******************************************************************--
-- Copyright (c) 1999-2000  Evatronix Ltd.                           --
--*******************************************************************--
-- Please review the terms of the license agreement before using     --
-- this file. If you are not an authorized user, please destroy this --
-- source code file and notify Evatronix S.A. immediately that you   --
-- inadvertently received an unauthorized copy.                      --
--*******************************************************************--

-----------------------------------------------------------------------
-- Project name         : C8051
-- Project description  : C8051 Microcontroller Unit
--
-- File name            : LATCH.VHD
-- File contents        : Entity EXTERNAL_LATCH_REGISTER
--                        Architecture SIM of EXTERNAL_LATCH_REGISTER
-- Purpose              : Data latch register
--
-- Destination library  : C8051_LIB
-- Dependencies         : IEEE.STD_LOGIC_1164
--
-- Design Engineer      : M.B.
-- Quality Engineer     : M.B.
-- Version              : 3.01
-- Last modification    : 2001-10-01
-----------------------------------------------------------------------

library IEEE;
   use IEEE.STD_LOGIC_1164.all;

entity EXTERNAL_LATCH_REGISTER is
  generic (
        DATAWIDTH       : NATURAL := 8
       );
  port (
        strobe          : in  STD_LOGIC;
        databusi        : in  STD_LOGIC_VECTOR (DATAWIDTH-1 downto 0);
        databuso        : out STD_LOGIC_VECTOR (DATAWIDTH-1 downto 0)
       );
end EXTERNAL_LATCH_REGISTER;

--**************************************************************************--

architecture SIM of EXTERNAL_LATCH_REGISTER is

begin

  ---------------------------------------------------------------------------
  latch_proc :
  ---------------------------------------------------------------------------
  process (strobe, databusi)
  begin
    if strobe='1' then
      databuso <= TO_X01(databusi) after 1 ns; 
    end if;
  end process;

end SIM;
--**************************************************************************--