Subversion Repositories System09

--===========================================================================----

--

--  S Y N T H E Z I A B L E    System09 - SOC.

--

--  www.OpenCores.Org - September 2003

--  This core adheres to the GNU public license  

--

-- File name      : System09.vhd

--

-- Purpose        : Top level file for 6809 compatible system on a chip

--                  Designed with Xilinx XC3S200 Spartan 3 FPGA.

--                  Implemented With Digilent Xilinx Starter FPGA board,

--

-- Dependencies   : ieee.Std_Logic_1164

--                  ieee.std_logic_unsigned

--                  ieee.std_logic_arith

--                  ieee.numeric_std

--

-- Uses           : mon_rom   (sys09bug_rom4k_b16.vhd) Monitor ROM

--                  cpu09     (cpu09.vhd)              CPU core

--                  dat_ram   (datram.vhd)             Dynamic Address Translation

--                  acia_6850 (acia_6850.vhd)          ACIA (UART)

--                            (acia_rx.vhd)

--                            (acia_tx.vhd)

--                  keyboard  (keyboard.vhd)           PS/2 Keyboard

--                            (ps2_keyboard.vhd)

--                            (keymap_rom)

--                  vdu8      (vdu8.vhd)                          Video Display Unit

--                            (char_rom2K_b16.vhd)

--                            (ram2k_b16.vhd)

--                  seven_segment (SevenSegment.vhd)   Seven Segment Display

-- 

-- Author         : John E. Kent      

--                  dilbert57@opencores.org      

--

--===========================================================================----

--

-- Revision History:

--===========================================================================--

-- Version 0.1 - 20 March 2003

-- Version 0.2 - 30 March 2003

-- Version 0.3 - 29 April 2003

-- Version 0.4 - 29 June 2003

--

-- Version 0.5 - 19 July 2003

-- prints out "Hello World"

--

-- Version 0.6 - 5 September 2003

-- Runs SBUG

--

-- Version 1.0- 6 Sep 2003 - John Kent

-- Inverted sys_clk

-- Initial release to Open Cores

--

-- Version 1.1 - 17 Jan 2004 - John Kent

-- Updated miniUart.

--

-- Version 1.2 - 25 Jan 2004 - John Kent

-- removed signals "test_alu" and "test_cc" 

-- Trap hardware re-instated.

--

-- Version 1.3 - 11 Feb 2004 - John Kent

-- Designed forked off to produce System09_VDU

-- Added VDU component

--      VDU runs at 25MHz and divides the clock by 2 for the CPU

-- UART Runs at 57.6 Kbps

--

-- Version 2.0 - 2 September 2004 - John Kent

-- ported to Digilent Xilinx Spartan3 starter board

--      removed Compaact Flash and Trap Logic.

-- Replaced SBUG with KBug9s

--

-- Version 2.1 - 21 November 2006 - John Kent

-- Replaced KBug9s with Sys09bug 1.0

-- Inverted bottom nybble of DAT register outputs

-- Changed ROM & I/O decoding to be compatible with SWTPc

-- Upped the serial baud rate to 115.2 KBd

-- added multiple global clock buffers

-- (Uart would not operate correctly)

--

-- Version 2.2 - 22 December 2006 - John Kent

-- Increased CPU clock from 12.5MHz to 25 MHz.

-- Removed some of the global clock buffers

-- Added LED output register

-- Changed address decoding to 4K Blocks

--

-- Version 2.3 - 1 June 2007 - John Kent

-- Updated VDU & ACIA

-- Changed decoding for Sys09Bug

--

-- Version 2.4 - 31 January 2008 - John Kent

--      ACIA does not appear to work.

-- Made RAM OE and WE strobes synchonous to sys_clk

--

--===========================================================================--

library ieee;

   use ieee.std_logic_1164.all;

   use IEEE.STD_LOGIC_ARITH.ALL;

   use IEEE.STD_LOGIC_UNSIGNED.ALL;

   use ieee.numeric_std.all;

entity my_system09 is

  port(

    sys_clk     : in  Std_Logic;  -- System Clock input

         rst_sw    : in  Std_logic;  -- Master Reset input (active high)

         nmi_sw      : in  Std_logic;

    -- Memory Interface signals

    ram_addr    : out Std_Logic_Vector(17 downto 0);

    ram_wen     : out Std_Logic;

    ram_oen     : out Std_Logic;

    ram1_cen    : out Std_Logic;

         ram1_ubn    : out Std_Logic;

         ram1_lbn    : out Std_Logic;

    ram1_data   : inout Std_Logic_Vector(15 downto 0);

    ram2_cen    : out Std_Logic;

         ram2_ubn    : out Std_Logic;

         ram2_lbn    : out Std_Logic;

    ram2_data   : inout Std_Logic_Vector(15 downto 0);

         -- PS/2 Keyboard

         ps2c        : inout Std_logic;

         ps2d        : inout Std_Logic;

         -- ACIA Interface

    rxd         : in  Std_Logic;

         txd         : out Std_Logic;

         -- CRTC output signals

         vs          : out Std_Logic;

    hs          : out Std_Logic;

    blue        : out std_logic;

    green       : out std_logic;

    red         : out std_logic;

         -- LEDS & Switches

         leds        : out std_logic_vector(7 downto 0);

         switches    : in  std_logic_vector(7 downto 0);

         -- seven segment display

         segments    : out std_logic_vector(7 downto 0);

         digits      : out std_logic_vector(3 downto 0)

         );

end my_system09;

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

-- Architecture for System09

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

architecture my_computer of my_system09 is

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

  -- constants

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

  constant SYS_Clock_Frequency  : integer := 50000000;  -- FPGA System Clock

  constant VGA_Clock_Frequency  : integer := 25000000;  -- VGA Pixel Clock

  constant CPU_Clock_Frequency  : integer := 25000000;  -- CPU Clock

  constant BAUD_Rate            : integer := 57600;       -- Baud Rate

  constant ACIA_Clock_Frequency : integer := BAUD_Rate * 16;

  type hold_state_type is ( hold_release_state, hold_request_state );

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

  -- Signals

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

  -- BOOT ROM

  signal rom_cs        : Std_logic;

  signal rom_data_out  : Std_Logic_Vector(7 downto 0);

  -- FLEX9 RAM

  signal flex_cs       : Std_logic;

  signal flex_data_out : Std_Logic_Vector(7 downto 0);

  -- ACIA Interface signals

  signal acia_clk      : std_logic;

  signal acia_data_out : Std_Logic_Vector(7 downto 0);

  signal acia_cs       : Std_Logic;

  signal acia_irq      : Std_Logic;

  signal acia_rxd      : Std_Logic;

  signal acia_txd      : Std_Logic;

  signal acia_dcd_n    : Std_Logic;

--  signal acia_rts_n    : Std_Logic;

  signal acia_cts_n    : Std_Logic;

  -- keyboard port

  signal keyboard_data_out : std_logic_vector(7 downto 0);

  signal keyboard_cs       : std_logic;

  signal keyboard_irq      : std_logic;

  -- LEDs

  signal leds_data_out : std_logic_vector(7 downto 0);

  signal leds_cs       : std_logic;

  -- RAM

  signal ram_cs       : std_logic; -- memory chip select

  signal ram_data_out : std_logic_vector(7 downto 0);

  signal ram1_ce      : std_logic;

  signal ram1_ub      : std_logic;

  signal ram1_lb      : std_logic;

  signal ram2_ce      : std_logic;

  signal ram2_ub      : std_logic;

  signal ram2_lb      : std_logic;

  signal ram_we       : std_logic;

  signal ram_oe       : std_logic;

  -- CPU Interface signals

  signal cpu_reset    : Std_Logic;

  signal cpu_clk      : Std_Logic;

  signal cpu_rw       : std_logic;

  signal cpu_vma      : std_logic;

  signal cpu_halt     : std_logic;

  signal cpu_hold     : std_logic;

  signal cpu_firq     : std_logic;

  signal cpu_irq      : std_logic;

  signal cpu_nmi      : std_logic;

  signal cpu_addr     : std_logic_vector(15 downto 0);

  signal cpu_data_in  : std_logic_vector(7 downto 0);

  signal cpu_data_out : std_logic_vector(7 downto 0);

  -- Dynamic Address Translation

  signal dat_cs       : std_logic;

  signal dat_addr     : std_logic_vector(7 downto 0);

  -- Video Display Unit

  signal vdu_cs       : std_logic;

  signal vdu_data_out : std_logic_vector(7 downto 0);

  signal vga_clk      : std_logic;

  -- 7 Segment Display

  signal seg_cs       : std_logic;

  signal seg_data_out : std_logic_vector(7 downto 0);

  -- System Clock Prescaler

  signal clk_count    : std_logic;

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

--

-- CPU09 CPU core

--

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

component cpu09

  port (

         clk      :     in  std_logic;

    rst      : in  std_logic;

    rw       :  out std_logic;          -- Asynchronous memory interface

    vma      :  out std_logic;

    address  : out std_logic_vector(15 downto 0);

    data_in  : in        std_logic_vector(7 downto 0);

         data_out : out std_logic_vector(7 downto 0);

         halt     : in  std_logic;

         hold     : in  std_logic;

         irq      : in  std_logic;

         nmi      : in  std_logic;

         firq     : in  std_logic

  );

end component;

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

--

-- 4KByte Block RAM Monitor ROM

--

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

component mon_rom

  Port (

    clk      : in  std_logic;

    rst      : in  std_logic;

    cs       : in  std_logic;

    rw       : in  std_logic;

    addr     : in  std_logic_vector (11 downto 0);

    data_out    : out std_logic_vector (7 downto 0);

    data_in    : in  std_logic_vector (7 downto 0)

    );

end component;

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

--

-- 8KBytes Block RAM for FLEX9

-- $C000 - $DFFF

--

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

component flex_ram

  Port (

    clk      : in  std_logic;

    rst      : in  std_logic;

    cs       : in  std_logic;

    rw       : in  std_logic;

    addr     : in  std_logic_vector (12 downto 0);

    data_out    : out std_logic_vector (7 downto 0);

    data_in    : in  std_logic_vector (7 downto 0)

    );

end component;

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

--

-- Dynamic Address Translation Registers

--

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

component dat_ram

  port (

    clk      : in  std_logic;

         rst      : in  std_logic;

         cs       : in  std_logic;

         rw       : in  std_logic;

         addr_lo  : in  std_logic_vector(3 downto 0);

         addr_hi  : in  std_logic_vector(3 downto 0);

    data_in  : in  std_logic_vector(7 downto 0);

         data_out : out std_logic_vector(7 downto 0)

  );

end component;

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

--

-- 6850 ACIA

--

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

component ACIA_6850

  port (

    clk      : in  Std_Logic;  -- System Clock

    rst      : in  Std_Logic;  -- Reset input (active high)

    cs       : in  Std_Logic;  -- ACIA Chip Select

    rw       : in  Std_Logic;  -- Read / Not Write

    irq      : out Std_Logic;  -- Interrupt

    Addr     : in  Std_Logic;  -- Register Select

    DataIn   : in  Std_Logic_Vector(7 downto 0); -- Data Bus In 

    DataOut  : out Std_Logic_Vector(7 downto 0); -- Data Bus Out

    RxC      : in  Std_Logic;  -- Receive Baud Clock

    TxC      : in  Std_Logic;  -- Transmit Baud Clock

    RxD      : in  Std_Logic;  -- Receive Data

    TxD      : out Std_Logic;  -- Transmit Data

         DCD_n    : in  Std_Logic;  -- Data Carrier Detect

    CTS_n    : in  Std_Logic;  -- Clear To Send

    RTS_n    : out Std_Logic   -- Request To send

  );

end component;

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

--

-- ACIA Clock divider

--

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

component ACIA_Clock

  generic (

     SYS_Clock_Frequency  : integer :=  SYS_Clock_Frequency;

          ACIA_Clock_Frequency : integer := ACIA_Clock_Frequency

  );

  port (

     clk      : in  Std_Logic;  -- System Clock Input

          ACIA_clk : out Std_logic   -- ACIA Clock output

  );

end component;

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

--

-- PS/2 Keyboard

--

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

component keyboard

  generic(

  KBD_Clock_Frequency : integer := CPU_Clock_Frequency

  );

  port(

  clk             : in    std_logic;

  rst             : in    std_logic;

  cs              : in    std_logic;

  rw              : in    std_logic;

  addr            : in    std_logic;

  data_in         : in    std_logic_vector(7 downto 0);

  data_out        : out   std_logic_vector(7 downto 0);

  irq             : out   std_logic;

  kbd_clk         : inout std_logic;

  kbd_data        : inout std_logic

  );

end component;

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

--

-- Video Display Unit.

--

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

component vdu8

      generic(

        VDU_CLOCK_FREQUENCY    : integer := CPU_Clock_Frequency; -- HZ

        VGA_CLOCK_FREQUENCY    : integer := VGA_Clock_Frequency; -- HZ

             VGA_HOR_CHARS          : integer := 80; -- CHARACTERS

             VGA_VER_CHARS          : integer := 25; -- CHARACTERS

             VGA_PIXELS_PER_CHAR    : integer := 8;  -- PIXELS

             VGA_LINES_PER_CHAR     : integer := 16; -- LINES

             VGA_HOR_BACK_PORCH     : integer := 40; -- PIXELS

             VGA_HOR_SYNC           : integer := 96; -- PIXELS

             VGA_HOR_FRONT_PORCH    : integer := 24; -- PIXELS

             VGA_VER_BACK_PORCH     : integer := 13; -- LINES

             VGA_VER_SYNC           : integer := 1;  -- LINES

             VGA_VER_FRONT_PORCH    : integer := 36  -- LINES

      );

      port(

                -- control register interface

      vdu_clk      : in  std_logic;      -- CPU Clock - 12.5MHz

      vdu_rst      : in  std_logic;

                vdu_cs       : in  std_logic;

                vdu_rw       : in  std_logic;

                vdu_addr     : in  std_logic_vector(2 downto 0);

      vdu_data_in  : in  std_logic_vector(7 downto 0);

      vdu_data_out : out std_logic_vector(7 downto 0);

      -- vga port connections

                vga_clk      : in  std_logic;   -- VGA Pixel Clock - 25 MHz

      vga_red_o    : out std_logic;

      vga_green_o  : out std_logic;

      vga_blue_o   : out std_logic;

      vga_hsync_o  : out std_logic;

      vga_vsync_o  : out std_logic

   );

end component;

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

--

-- Seven Segment Display driver

--

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

component seven_segment is

        port (

          clk         : in  std_logic;

     rst         : in  std_logic;

     cs          : in  std_logic;

     rw          : in  std_logic;

     addr        : in  std_logic_vector(1 downto 0);

     data_in     : in  std_logic_vector(7 downto 0);

          data_out    : out std_logic_vector(7 downto 0);

          segments    : out std_logic_vector(7 downto 0);

          digits             : out std_logic_vector(3 downto 0)

        );

end component;

component BUFG

  port (

    i            : in  std_logic;

    o            : out std_logic

  );

end component;

begin

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

  -- Instantiation of internal components

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

my_cpu : cpu09  port map (

         clk         => cpu_clk,

    rst       => cpu_reset,

    rw       => cpu_rw,

    vma       => cpu_vma,

    address   => cpu_addr(15 downto 0),

    data_in   => cpu_data_in,

         data_out  => cpu_data_out,

         halt      => cpu_halt,

         hold      => cpu_hold,

         irq       => cpu_irq,

         nmi       => cpu_nmi,

         firq      => cpu_firq

    );

my_rom : mon_rom port map (

    clk       => cpu_clk,

    rst       => cpu_reset,

         cs        => rom_cs,

         rw        => '1',

    addr      => cpu_addr(11 downto 0),

    data_out     => rom_data_out,

    data_in     => cpu_data_out

    );

my_flex : flex_ram port map (

    clk       => cpu_clk,

    rst       => cpu_reset,

         cs        => flex_cs,

         rw        => cpu_rw,

    addr      => cpu_addr(12 downto 0),

    data_out     => flex_data_out,

    data_in     => cpu_data_out

    );

my_dat : dat_ram port map (

    clk       => cpu_clk,

         rst       => cpu_reset,

         cs        => dat_cs,

         rw        => cpu_rw,

         addr_hi   => cpu_addr(15 downto 12),

         addr_lo   => cpu_addr(3 downto 0),

    data_in   => cpu_data_out,

         data_out  => dat_addr(7 downto 0)

         );

my_acia  : ACIA_6850 port map (

         clk         => cpu_clk,

         rst       => cpu_reset,

    cs        => acia_cs,

         rw        => cpu_rw,

    irq       => acia_irq,

    Addr      => cpu_addr(0),

         Datain    => cpu_data_out,

         DataOut   => acia_data_out,

         RxC       => acia_clk,

         TxC       => acia_clk,

         RxD       => acia_rxd,

         TxD       => acia_txd,

         DCD_n     => acia_dcd_n,

         CTS_n     => acia_cts_n,

         RTS_n     => open

         );

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

--

-- ACIA Clock

--

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

my_ACIA_Clock : ACIA_Clock

  generic map(

    SYS_Clock_Frequency  => SYS_Clock_Frequency,

         ACIA_Clock_Frequency => ACIA_Clock_Frequency

  )

  port map(

    clk        => sys_clk,

    acia_clk   => acia_clk

  );

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

--

-- PS/2 Keyboard Interface

--

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

my_keyboard : keyboard

   generic map (

        KBD_Clock_Frequency => CPU_Clock_frequency

        )

   port map(

        clk          => cpu_clk,

        rst          => cpu_reset,

        cs           => keyboard_cs,

        rw           => cpu_rw,

        addr         => cpu_addr(0),

        data_in      => cpu_data_out(7 downto 0),

        data_out     => keyboard_data_out(7 downto 0),

        irq          => keyboard_irq,

        kbd_clk      => ps2c,

        kbd_data     => ps2d

        );

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

--

-- Video Display Unit instantiation

--

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

my_vdu : vdu8

  generic map(

      VDU_CLOCK_FREQUENCY    => CPU_Clock_Frequency, -- HZ

      VGA_CLOCK_FREQUENCY    => VGA_Clock_Frequency, -- HZ

           VGA_HOR_CHARS          => 80, -- CHARACTERS

           VGA_VER_CHARS          => 25, -- CHARACTERS

           VGA_PIXELS_PER_CHAR    => 8,  -- PIXELS

           VGA_LINES_PER_CHAR     => 16, -- LINES

           VGA_HOR_BACK_PORCH     => 40, -- PIXELS

           VGA_HOR_SYNC           => 96, -- PIXELS

           VGA_HOR_FRONT_PORCH    => 24, -- PIXELS

           VGA_VER_BACK_PORCH     => 13, -- LINES

           VGA_VER_SYNC           => 1,  -- LINES

           VGA_VER_FRONT_PORCH    => 36  -- LINES

  )

  port map(

                -- Control Registers

                vdu_clk       => cpu_clk,                                        -- 12.5 MHz System Clock in

      vdu_rst       => cpu_reset,

                vdu_cs        => vdu_cs,

                vdu_rw        => cpu_rw,

                vdu_addr      => cpu_addr(2 downto 0),

                vdu_data_in   => cpu_data_out,

                vdu_data_out  => vdu_data_out,

      -- vga port connections

      vga_clk       => vga_clk,                                  -- 25 MHz VDU pixel clock

      vga_red_o     => red,

      vga_green_o   => green,

      vga_blue_o    => blue,

      vga_hsync_o   => hs,

      vga_vsync_o   => vs

   );

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

--

-- Seven Segment Display instantiation

--

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

my_seg : seven_segment port map (

    clk        => cpu_clk,

         rst        => cpu_reset,

         cs         => seg_cs,

         rw         => cpu_rw,

         addr       => cpu_addr(1 downto 0),

    data_in    => cpu_data_out,

         data_out   => seg_data_out,

         segments   => segments,

         digits     => digits

         );

vga_clk_buffer : BUFG port map(

    i => clk_count,

         o => vga_clk

    );

cpu_clk_buffer : BUFG port map(

    i => clk_count,

         o => cpu_clk

    );

--

-- Clock divider

-- Assumes 50 MHz system clock

-- 25MHz pixel clock

-- 25MHz CPU clock

--

sys09_clock : process( sys_clk, clk_count )

begin

        if sys_clk'event and sys_clk='1' then

           clk_count <= not clk_count;

   end if;

end process;

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

--

-- Process to decode memory map

--

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

mem_decode: process( cpu_addr, cpu_rw, cpu_vma,

                                              dat_cs, dat_addr,

                                              rom_data_out,

                                                   acia_data_out,

                                                        keyboard_data_out,

                                                        vdu_data_out,

                                                        seg_data_out,

                                                        leds_data_out,

                                                        flex_data_out,

                                                        ram_data_out

                                                        )

begin

      cpu_data_in <= (others=>'0');

      dat_cs      <= '0';

      rom_cs      <= '0';

      acia_cs     <= '0';

      keyboard_cs <= '0';

      vdu_cs      <= '0';

      seg_cs      <= '0';

      leds_cs     <= '0';

      flex_cs     <= '0';

      ram_cs      <= '0';

--           timer_cs    <= '0';

--      trap_cs     <= '0';

--           pb_cs       <= '0';

--      ide_cs      <= '0';

--      ether_cs    <= '0';

--           slot1_cs    <= '0';

--      slot2_cs    <= '0';

      if cpu_addr( 15 downto 8 ) = "11111111" then

             cpu_data_in <= rom_data_out;

        dat_cs      <= cpu_vma;              -- write DAT

        rom_cs      <= cpu_vma;              -- read  ROM

           --

                -- Sys09Bug Monitor ROM $F000 - $FFFF

                --

           elsif dat_addr(3 downto 0) = "1111" then -- $XF000 - $XFFFF

           --

                -- Monitor ROM $F000 - $FFFF

                --

        cpu_data_in <= rom_data_out;

        rom_cs      <= cpu_vma;          -- read  ROM

      --

                -- IO Devices $E000 - $EFFF

                --