Subversion Repositories t48

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--

-- T8048 Microcontroller System

-- 8048 toplevel without tri-states

--

-- $Id: t8048_notri.vhd,v 1.5 2006-06-20 00:47:08 arniml Exp $

--

-- Copyright (c) 2004, Arnim Laeuger (arniml@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/t48/

--

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

library ieee;

use ieee.std_logic_1164.all;

entity t8048_notri is

  generic (

    gate_port_input_g : integer := 1

  );

  port (

    xtal_i        : in  std_logic;

    xtal_en_i     : in  std_logic;

    reset_n_i     : in  std_logic;

    t0_i          : in  std_logic;

    t0_o          : out std_logic;

    t0_dir_o      : out std_logic;

    int_n_i       : in  std_logic;

    ea_i          : in  std_logic;

    rd_n_o        : out std_logic;

    psen_n_o      : out std_logic;

    wr_n_o        : out std_logic;

    ale_o         : out std_logic;

    db_i          : in  std_logic_vector( 7 downto 0);

    db_o          : out std_logic_vector( 7 downto 0);

    db_dir_o      : out std_logic;

    t1_i          : in  std_logic;

    p2_i          : in  std_logic_vector( 7 downto 0);

    p2_o          : out std_logic_vector( 7 downto 0);

    p2l_low_imp_o : out std_logic;

    p2h_low_imp_o : out std_logic;

    p1_i          : in  std_logic_vector( 7 downto 0);

    p1_o          : out std_logic_vector( 7 downto 0);

    p1_low_imp_o  : out std_logic;

    prog_n_o      : out std_logic

  );

end t8048_notri;

library ieee;

use ieee.numeric_std.all;

use work.t48_core_comp_pack.t48_core;

use work.t48_core_comp_pack.syn_rom;

use work.t48_core_comp_pack.syn_ram;

architecture struct of t8048_notri is

  -- Address width of internal ROM

  constant rom_addr_width_c : natural := 10;

  signal xtal3_s          : std_logic;

  signal dmem_addr_s      : std_logic_vector( 7 downto 0);

  signal dmem_we_s        : std_logic;

  signal dmem_data_from_s : std_logic_vector( 7 downto 0);

  signal dmem_data_to_s   : std_logic_vector( 7 downto 0);

  signal pmem_addr_s      : std_logic_vector(11 downto 0);

  signal pmem_data_s      : std_logic_vector( 7 downto 0);

  signal ea_s             : std_logic;

  signal p1_in_s,

         p1_out_s         : std_logic_vector( 7 downto 0);

  signal p2_in_s,

         p2_out_s         : std_logic_vector( 7 downto 0);

begin

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

  -- Check generics for valid values.

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

  -- pragma translate_off

  assert gate_port_input_g = 0 or gate_port_input_g = 1

    report "gate_port_input_g must be either 1 or 0!"

    severity failure;

  -- pragma translate_on

  t48_core_b : t48_core

    generic map (

      xtal_div_3_g        => 1,

      register_mnemonic_g => 1,

      include_port1_g     => 1,

      include_port2_g     => 1,

      include_bus_g       => 1,

      include_timer_g     => 1,

      sample_t1_state_g   => 4

    )

    port map (

      xtal_i        => xtal_i,

      xtal_en_i     => xtal_en_i,

      reset_i       => reset_n_i,

      t0_i          => t0_i,

      t0_o          => t0_o,

      t0_dir_o      => t0_dir_o,

      int_n_i       => int_n_i,

      ea_i          => ea_s,

      rd_n_o        => rd_n_o,

      psen_n_o      => psen_n_o,

      wr_n_o        => wr_n_o,

      ale_o         => ale_o,

      db_i          => db_i,

      db_o          => db_o,

      db_dir_o      => db_dir_o,

      t1_i          => t1_i,

      p2_i          => p2_in_s,

      p2_o          => p2_out_s,

      p2l_low_imp_o => p2l_low_imp_o,

      p2h_low_imp_o => p2h_low_imp_o,

      p1_i          => p1_in_s,

      p1_o          => p1_out_s,

      p1_low_imp_o  => p1_low_imp_o,

      prog_n_o      => prog_n_o,

      clk_i         => xtal_i,

      en_clk_i      => xtal3_s,

      xtal3_o       => xtal3_s,

      dmem_addr_o   => dmem_addr_s,

      dmem_we_o     => dmem_we_s,

      dmem_data_i   => dmem_data_from_s,

      dmem_data_o   => dmem_data_to_s,

      pmem_addr_o   => pmem_addr_s,

      pmem_data_i   => pmem_data_s

    );

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

  -- Gate port 1 and 2 input bus with respetive output value

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

  gate_ports: if gate_port_input_g = 1 generate

    p1_in_s <= p1_i and p1_out_s;

    p2_in_s <= p2_i and p2_out_s;

  end generate;

  pass_ports: if gate_port_input_g = 0 generate

    p1_in_s <= p1_i;

    p2_in_s <= p2_i;

  end generate;

  p1_o <= p1_out_s;

  p2_o <= p2_out_s;

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

  -- Process ea

  --

  -- Purpose:

  --   Detects access to external program memory.

  --   Either by ea_i = '1' or when program memory address leaves address

  --   range of internal ROM.

  --

  ea: process (ea_i,

               pmem_addr_s)

  begin

    if ea_i = '1' then

      -- Forced external access

      ea_s <= '1';

    elsif unsigned(pmem_addr_s(11 downto rom_addr_width_c)) = 0 then

      -- Internal access

      ea_s <= '0';

    else

      -- Access to program memory out of internal range

      ea_s <= '1';

    end if;

  end process ea;

  --

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

  rom_1k_b : syn_rom

    generic map (

      address_width_g => rom_addr_width_c

    )

    port map (

      clk_i      => xtal_i,

      rom_addr_i => pmem_addr_s(rom_addr_width_c-1 downto 0),

      rom_data_o => pmem_data_s

    );

  ram_64_b : syn_ram

    generic map (

      address_width_g => 6

    )

    port map (

      clk_i      => xtal_i,

      res_i      => reset_n_i,

      ram_addr_i => dmem_addr_s(5 downto 0),

      ram_data_i => dmem_data_to_s,

      ram_we_i   => dmem_we_s,

      ram_data_o => dmem_data_from_s

    );

end struct;

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

-- File History:

--

-- $Log: not supported by cvs2svn $

-- Revision 1.4  2005/11/01 21:38:48  arniml

-- wire signals for P2 low impedance marker issue

--

-- Revision 1.3  2004/12/02 22:08:42  arniml

-- introduced generic gate_port_input_g

-- forces masking of P1 and P2 input bus

--

-- Revision 1.2  2004/12/01 23:08:08  arniml

-- update

--

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