Subversion Repositories xmatchpro

--This library is free software; you can redistribute it and/or

--modify it under the terms of the GNU Lesser General Public

--License as published by the Free Software Foundation; either

--version 2.1 of the License, or (at your option) any later version.

--This library is distributed in the hope that it will be useful,

--but WITHOUT ANY WARRANTY; without even the implied warranty of

--MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

--Lesser General Public License for more details.

--You should have received a copy of the GNU Lesser General Public

--License along with this library; if not, write to the Free Software

--Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

-- e_mail : j.l.nunez-yanez@byacom.co.uk

---------------------------------

--  ENTITY       = OV_LATCH    --

--  version      = 1.0         --

--  last update  = 30/07/98    --

--  author       = Jose Nunez  --

---------------------------------

-- FUNCTION

-- 1 bit latch for generation of overflow signals to memory address

-- generation logic and ob-assembler logic.

-- PIN LIST

-- OVERFLOW_LENGTH = indicates a length overflow (active LOW)

-- OVERFLOW_FLUSH  = indicates a flushing overflow (active LOW)

-- PRESET          = asynchronous setting of latch

-- CLK             = master clock

-- OVERFLOW_MEM    = overflow signal to memory address generation logic

-- OVERFLOW_OLD    = clocked version of OVERFLOW_LENGTH

entity OV_LATCH is

port

(

        OVERFLOW_LENGTH : in bit;

        OVERFLOW_FLUSH : in bit;

        CLEAR : in bit;

        RESET : in bit;

        CLK : in bit;

        OVERFLOW_MEM : out bit;

        OVERFLOW_OLD : out bit

);

end OV_LATCH;

architecture FLIP_FLOP of OV_LATCH is

signal TEMP_Q : bit;

begin

OVERFLOW_MEM <= TEMP_Q and OVERFLOW_FLUSH;

OVERFLOW_OLD <= TEMP_Q;

FLOP : process (CLK,CLEAR)

begin

if (CLEAR = '0') then

    TEMP_Q <= '1';

elsif ((CLK'event) and (CLK = '1')) then

    if (RESET = '0') then

        TEMP_Q <= '1';

    else

        TEMP_Q <= OVERFLOW_LENGTH;

    end if;

end if;

end process FLOP;

end FLIP_FLOP; -- end of architecture