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[/] [z80soc/] [branches/] [RonivonCosta/] [rtl/] [VHDL/] [t80/] [T80s.vhd.bak] - Rev 42
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--
-- Z80 compatible microprocessor core, synchronous top level
-- Different timing than the original z80
-- Inputs needs to be synchronous and outputs may glitch
--
-- Version : 0242
--
-- Copyright (c) 2001-2002 Daniel Wallner (jesus@opencores.org)
--
-- All rights reserved
--
-- Redistribution and use in source and synthezised forms, with or without
-- modification, are permitted provided that the following conditions are met:
--
-- Redistributions of source code must retain the above copyright notice,
-- this list of conditions and the following disclaimer.
--
-- Redistributions in synthesized form must reproduce the above copyright
-- notice, this list of conditions and the following disclaimer in the
-- documentation and/or other materials provided with the distribution.
--
-- Neither the name of the author nor the names of other contributors may
-- be used to endorse or promote products derived from this software without
-- specific prior written permission.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
-- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-- POSSIBILITY OF SUCH DAMAGE.
--
-- Please report bugs to the author, but before you do so, please
-- make sure that this is not a derivative work and that
-- you have the latest version of this file.
--
-- The latest version of this file can be found at:
-- http://www.opencores.org/cvsweb.shtml/t80/
--
-- Limitations :
--
-- File history :
--
-- 0208 : First complete release
--
-- 0210 : Fixed read with wait
--
-- 0211 : Fixed interrupt cycle
--
-- 0235 : Updated for T80 interface change
--
-- 0236 : Added T2Write generic
--
-- 0237 : Fixed T2Write with wait state
--
-- 0238 : Updated for T80 interface change
--
-- 0240 : Updated for T80 interface change
--
-- 0242 : Updated for T80 interface change
--
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use work.T80_Pack.all;
entity T80s is
generic(
Mode : integer := 0; -- 0 => Z80, 1 => Fast Z80, 2 => 8080, 3 => GB
T2Write : integer := 0; -- 0 => WR_n active in T3, /=0 => WR_n active in T2
IOWait : integer := 1 -- 0 => Single cycle I/O, 1 => Std I/O cycle
);
port(
RESET_n : in std_logic;
CLK_n : in std_logic;
WAIT_n : in std_logic;
INT_n : in std_logic;
NMI_n : in std_logic;
BUSRQ_n : in std_logic;
M1_n : out std_logic;
MREQ_n : out std_logic;
IORQ_n : out std_logic;
RD_n : out std_logic;
WR_n : out std_logic;
RFSH_n : out std_logic;
HALT_n : out std_logic;
BUSAK_n : out std_logic;
A : out std_logic_vector(15 downto 0);
DI : in std_logic_vector(7 downto 0);
DO : out std_logic_vector(7 downto 0)
);
end T80s;
architecture rtl of T80s is
signal CEN : std_logic;
signal IntCycle_n : std_logic;
signal NoRead : std_logic;
signal Write : std_logic;
signal IORQ : std_logic;
signal DI_Reg : std_logic_vector(7 downto 0);
signal MCycle : std_logic_vector(2 downto 0);
signal TState : std_logic_vector(2 downto 0);
begin
CEN <= '1';
u0 : T80
generic map(
Mode => Mode,
IOWait => IOWait)
port map(
CEN => CEN,
M1_n => M1_n,
IORQ => IORQ,
NoRead => NoRead,
Write => Write,
RFSH_n => RFSH_n,
HALT_n => HALT_n,
WAIT_n => Wait_n,
INT_n => INT_n,
NMI_n => NMI_n,
RESET_n => RESET_n,
BUSRQ_n => BUSRQ_n,
BUSAK_n => BUSAK_n,
CLK_n => CLK_n,
A => A,
DInst => DI,
DI => DI_Reg,
DO => DO,
MC => MCycle,
TS => TState,
IntCycle_n => IntCycle_n);
process (RESET_n, CLK_n)
begin
if RESET_n = '0' then
RD_n <= '1';
WR_n <= '1';
IORQ_n <= '1';
MREQ_n <= '1';
DI_Reg <= "00000000";
elsif CLK_n'event and CLK_n = '1' then
RD_n <= '1';
WR_n <= '1';
IORQ_n <= '1';
MREQ_n <= '1';
if MCycle = "001" then
if TState = "001" or (TState = "010" and Wait_n = '0') then
RD_n <= not IntCycle_n;
MREQ_n <= not IntCycle_n;
IORQ_n <= IntCycle_n;
end if;
if TState = "011" then
MREQ_n <= '0';
end if;
else
if (TState = "001" or (TState = "010" and Wait_n = '0')) and NoRead = '0' and Write = '0' then
RD_n <= '0';
IORQ_n <= not IORQ;
MREQ_n <= IORQ;
end if;
if T2Write = 0 then
if TState = "010" and Write = '1' then
WR_n <= '0';
IORQ_n <= not IORQ;
MREQ_n <= IORQ;
end if;
else
if (TState = "001" or (TState = "010" and Wait_n = '0')) and Write = '1' then
WR_n <= '0';
IORQ_n <= not IORQ;
MREQ_n <= IORQ;
end if;
end if;
end if;
if TState = "010" and Wait_n = '1' then
DI_Reg <= DI;
end if;
end if;
end process;
end;
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