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--===========================================================================--
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--===========================================================================--
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--
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-- --
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-- S Y N T H E Z I A B L E Dynamic Address Translation Registers
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-- Synthesizable SWTPc 6809 Dynamic Address Translation Table --
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--
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-- --
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-- www.OpenCores.Org - December 2002
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--===========================================================================--
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-- This core adheres to the GNU public license
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--
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--
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-- File name : datram.vhd
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-- File name : datram.vhd
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--
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--
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-- entity name : dat_ram
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-- Entity name : dat_ram
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--
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--
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-- Purpose : Implements a Dynamic Address Translation RAM module
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-- Purpose : Implements a Dynamic Address Translation RAM module
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-- as found in the SWTPc MP-09 CPU card.
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-- Maps the high order 4 address bits to 8 address lines
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-- Maps the high order 4 address bits to 8 address lines
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-- extending the memory addressing range to 1 Mbytes
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-- extending the memory addressing range from 64K to 1MByte
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-- Memory segments are mapped on 4 KByte boundaries
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-- Memory segments are mapped on 4 KByte boundaries
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-- The DAT registers map to the top of memory
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-- The DAT registers are mapped at the the top of memory
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-- ($FFF0 - $FFFF) and are write only so can map behind ROM.
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-- ($FFF0 - $FFFF) and are write only so can map behind ROM.
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-- Since the DAT is not supported by SWTBUG for the 6800,
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-- Since the DAT is not supported by SWTBUG for the 6800,
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-- the resgisters reset state map the bottom 64K of RAM.
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-- the resgisters reset state map the bottom 64K of RAM.
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--
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--
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-- Dependencies : ieee.Std_Logic_1164
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-- Dependencies : ieee.std_logic_1164
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-- ieee.std_logic_unsigned
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-- ieee.std_logic_unsigned
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-- unisim.vcomponents
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--
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--
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-- Author : John E. Kent
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-- Author : John E. Kent
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--
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--
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--===========================================================================----
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-- Email : dilbert57@opencores.org
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--
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--
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-- Revision History:
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-- Web : http://opencores.org/project,system09
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--
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--
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-- Date Revision Author
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-- Description :
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-- 10 Nov 2002 0.1 John Kent
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--
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--
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-- 21 Nov 2006 0.2 John Kent
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-- Inverted bottom 4 bits of dat_addr
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-- so that it is compatible with SWTPc MP-09 card.
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-- DAT is initializedas follows:
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-- DAT is initializedas follows:
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--
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--
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-- DAT Dat Logical Physical
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-- DAT Dat Logical Physical
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-- Reg Val Addr Addr
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-- Reg Val Addr Addr
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-- fff0 - 0f - page 0 - $0xxx = $00xxx (RAM)
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-- fff0 - 0f - page 0 - $0xxx = $00xxx (RAM)
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-- fffb - 04 - page 0 - $bxxx = $0bxxx (RAM)
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-- fffb - 04 - page 0 - $bxxx = $0bxxx (RAM)
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-- fffc - 03 - page 0 - $cxxx = $0cxxx (RAM)
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-- fffc - 03 - page 0 - $cxxx = $0cxxx (RAM)
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-- fffd - 02 - page 0 - $dxxx = $0dxxx (RAM)
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-- fffd - 02 - page 0 - $dxxx = $0dxxx (RAM)
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-- fffe - f1 - page 0 - $exxx = $fexxx (I/O)
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-- fffe - f1 - page 0 - $exxx = $fexxx (I/O)
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-- ffff - f0 - page 0 - $fxxx = $ffxxx (ROM/DMFA2)
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-- ffff - f0 - page 0 - $fxxx = $ffxxx (ROM/DMFA2)
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--
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-- 25 Feb 2007 0.3 John Kent
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-- Copyright (C) 2003 - 2010 John Kent
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-- modify the sensitivity lists
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--
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-- This program is free software: you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation, either version 3 of the License, or
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-- (at your option) any later version.
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--
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-- This program is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with this program. If not, see <http://www.gnu.org/licenses/>.
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--
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--===========================================================================--
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-- --
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-- Revision History --
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-- --
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--===========================================================================--
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--
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-- Version Date Author Changes
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--
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-- 0.1 2002-11-10 John Kent Initial version
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--
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-- 0.2 2006-11-21 John Kent Inverted bottom 4 bits of dat_addr
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-- so that it is compatible with SWTPc MP-09 card.
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--
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-- 0.3 2007-02-25 John Kent Modify the sensitivity lists
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--
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-- 0.4 2010-06-17 John Kent Update header and added GPL
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--
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--
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library ieee;
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_unsigned.all;
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use ieee.std_logic_unsigned.all;
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| Line 67... |
Line 93... |
entity dat_ram is
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entity dat_ram is
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port (
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port (
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clk : in std_logic;
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clk : in std_logic;
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rst : in std_logic;
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rst : in std_logic;
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cs : in std_logic;
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cs : in std_logic;
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rw : in std_logic;
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addr_hi : in std_logic_vector(3 downto 0);
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addr_hi : in std_logic_vector(3 downto 0);
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addr_lo : in std_logic_vector(3 downto 0);
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addr_lo : in std_logic_vector(3 downto 0);
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rw : in std_logic;
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data_in : in std_logic_vector(7 downto 0);
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data_in : in std_logic_vector(7 downto 0);
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data_out : out std_logic_vector(7 downto 0));
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data_out : out std_logic_vector(7 downto 0));
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end dat_ram;
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end dat_ram;
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architecture rtl of dat_ram is
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architecture rtl of dat_ram is
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