Subversion Repositories t48

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--

-- T8048 Microcontroller System

-- 8048 toplevel without tri-states

--

-- $Id: t8048_notri.vhd,v 1.1 2004-12-01 23:07:21 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/

--

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library ieee;

use ieee.std_logic_1164.all;

entity t8048_notri is

  port (

    xtal_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);

    p2_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;

begin

  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,

      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_i,

      p2_o         => p2_o,

      p2_low_imp_o => p2_low_imp_o,

      p1_i         => p1_i,

      p1_o         => p1_o,

      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

    );

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

  -- 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;

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