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Document Title: [Gravitar_Space Duel.html (html file)]

CONVERSION BETWEEN SPACE DUEL AND GRAVITAR
From: "tomm" 
Subject: Re: Tech:  XY Gurus HELP Gravitar/Space Duel
Date: Monday, June 12, 2000 10:18 AM


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|          CONVERSION BETWEEN SPACE DUEL AND GRAVITAR           |
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COPYRIGHT 2000

REVISION NUMBER: 1.0 (first public release)
  REVISION DATE: 29 March 2000
     CREATED BY: John Lee and amended by Tom McClintock


PART I:    Conversion of A Space Duel Control Panel to Gravitar
PART II:   Gravitar Control Panel In A Space Duel Cabinet
PART III:  Other Helpful Space Duel/Gravitar Information


STANDARD DISCLAIMER:
--------------------
REMEMBER, NO WARRANTEES, EXPRESS OR IMPLIED, ARE GIVEN.  USE THIS
INFORMATION AT YOUR OWN RISK.  I AM NOT RESPONSIBLE FOR ANY
DAMAGES
THAT MAY OCCUR TO YOUR PERSON OR PROPERTY.


-----------------------------------------------------------------
------
PART I.
CONVERSION OF A SPACE DUEL CONTROL PANEL TO GRAVITAR
  by: Tom McClintock
-----------------------------------------------------------

GENERAL OVERVIEW:
-----------------
Having an Atari Space Duel cabinet and an extra Atari Gravitar
PCB, I
proceeded to come up with a simple and non-invasive way to play
Gravitar in my Space Duel cabinet. Since Space Duel and Gravitar
share
almost identical control panel layouts (aside from the fact that
Space Duel has two sets of controls while Gravitar has only one),
Gravitar can be easily incorporated into the cabinet with a small
control panel adapter harness.

The Space Duel cabinet wiring harness is pin compatible with a
Gravitar PCB, but the Gravitar PCB looks for player inputs on
different
pins than what the Space Duel control panel provides. So, a small
conversion harness must be inserted between the Space Duel
control
panel and the Space Duel wiring harness to send the correct
signals
to the Gravitar PCB. The Gravitar game PCB requires no
alterations
with this conversion. I chose the Player 2 controls on the Space
Duel
panel to act as the controls for Gravitar as they get used less
frequently. If you are so inclined, it is just as easy to map the
Player 1 controls to play Gravitar. The Start Switch becomes
"Player 1
Start" and the Select Switch becomes "Player 2 Start". The
"Shields"
button also acts as the Tractor button - exactly as the original
Gravitar control panel layout. The wires on the Space Duel
control
panel harness that are not explicitly listed are not connected.







INGREDIENTS:
------------
1 -  Working Gravitar Board
1 -  AMP 24-pin Miniature Rectangular Pin Housing (AMP#
1-640515-0)
1 -  AMP 24-pin Miniature Rectangular Socket Housing (AMP#
1-640525-0)
13 - AMP MR Live Split pins (or equivalent)
13 - AMP MR Standard Socket pins (or equivalent)
13 - Three-inch segments of 20 gauge insulated wire

[note: please check the AMP web site for distributors www.amp.com
]


HARNESS CONSTRUCTION:
---------------------


<------------------------------------------>
Space Duel to Gravitar Conversion Harness
   using Space Duel Player 2 controls

Space Duel CP		Space Duel Harness
        pin 1     to    pin 11
        pin 2     to    pin 9
        pin 3     to    pin 3
        pin 4     to    pin 14
        pin 5     to    pin 5
        pin 6     to    pin 13
        pin 7     to    pin 7
        pin 13    to    pin 6
        pin 14    to    pin 4
        pin 21    to    pin 21
        pin 22    to    pin 22
        pin 23    to    pin 23
        pin 24    to    pin 24
<------------------------------------------>


TROUBLESHOOTING:
----------------

 - Check the continuity on each harness wire before inserting it
into
   the AMP connector. This is obvious, but sometimes overlooked.

 - Before you insert each wire into its respective AMP connector,
   carefully note the male/female orientation of the pre-existing
   Space Duel harness(es). If a button is not working or is
operating
   a different feature, then check proper pin-to-pin connections.

 - Try to make the conversion harness as short as possible to
eliminate
   any unnecessary bending of the Space Duel cabinet harness.

 - The Space Duel PCB treats "Rotate Left" and "Rotate Right" in
an
   opposite way to the Gravitar PCB. Therefore, the adapter
harness
   inverts the left and right rotation for Gravitar. This will
only
   make sense if you are reviewing the pinouts - otherwise do not
worry
   about it.

 - The self test routines for a Gravitar PCB are the same as for
a
   Space Duel PCB with one difference. While Space Duel utilizes
the
   SLAM switch to step through the self test screens, Gravitar
uses the
   aux coin switch mounted next to the coin counter.



-----------------------------------------------------------------
------
PART II.

GRAVITAR CONTROL PANEL IN A SPACE DUEL CABINET:
   by John Lee (jhlee@hac2arpa.hac.com)
-----------------------------------------------------------

The following describes how to connect an Atari Gravitar control
panel
to the Atari Space Duel cabinet harness.  Both the Gravitar
control
panel and game PCB are virtual drop-in substitutes into the Space
Duel
cabinet.  However, while the Gravitar panel has a 12-pin
Molex-type
connector, Space Duel uses a 24-pin AMP connector [# 1-640515-0].

In my own conversion, I made a small adapter that plugs in
between the
Gravitar control panel and the Space Duel harness.  With this
adapter,
no alterations are made to the harness or control panels and it
is
easy to switch between the games.  The Gravitar game PCB requires
no
alterations.

The wires on the Space Duel harness that are not explicitly
listed are
not connected.  The pin numbers given are for connector J24/P24
on
both game's schematics (the connector at the control panel.) For
your
reference, the wire colors are included below.



HARNESS CONSTRUCTION:
---------------------


<------------------------------------------>
Space Duel to Gravitar Conversion Harness
     using a Gravitar Control Panel

  Gravitar CP		Space Duel Harness
        pin 1     to    pin 13
        pin 2     to    pin 7
        pin 3     to    pin 3
        pin 4     to    pin 9
        pin 5     to    pin 14
        pin 6     to    pin 5
        pin 7     to    pin 11
        pin 8     to    pin 6
        pin 9     to    pin 4
        pin 10    to    pin 21
        pin 11    to    pin 23
        pin 12    to    pin 24
<------------------------------------------>



-----------------------------------------------------------------
------
PART III.

OTHER HELPFUL SPACE DUEL/GRAVITAR INFORMATION:
----------------------------------------------


                   SPACE DUEL PINOUTS

                          P20
                        _______
                    GND |A | 1| GND
                    +5V |B | 2| +5V
                        |C | 3| +22V
                        |D | 4| -22V
                 +10.3V |E | 5|
                Lockout |F | 6| Coin Counter Right
      Coin Counter Left |H | 7| Select LED
              Start LED |J | 8| Rotate Left 2
         Rotate Left 1  |K | 9| Shield 2
               Shield 1 |L |10| Thrust 1
               Thrust 2 |M |11| Select Switch
             Switch GND |N |12| Switch GND
             Switch GND |P |13| Switch GND
                        |R |14| SLAM Switch
              Coin Aux. |S |15|
              Self Test |T |16| Coin Switch Left
      Coin Switch Right |U |17|
                        |V |18|
                        |W |19|
                        |X |20|
                    +5V |Y |21| +5V
                    GND |Z |22| GND
                        -------

                          P19
                        _______
                  X OUT |A | 1| X GND
                  Y OUT |B | 2| Y GND
                        |C | 3| Fire 1
                        |D | 4| Fire 2
         Rotate Right 2 |E | 5| Rotate Right 1
                        |F | 6| Start Switch
                Red GND |H | 7| Red
              Green GND |J | 8| Green
               Blue GND |K | 9| Blue
                        |L |10|
              Audio GND |M |11| Audio 2
                        |N |12| Audio 1
                        -------


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

                    GRAVITAR PINOUTS

                          P20
                        _______
                    GND |A | 1| GND
                    +5V |B | 2| +5V
                        |C | 3| +22V
                        |D | 4| -22V
                 +10.3V |E | 5|
                Lockout |F | 6| Coin Counter Right
      Coin Counter Left |H | 7| Player 1 LED
           Player 2 LED |J | 8|
                        |K | 9|
                        |L |10| Coin Switch Left
                Start 1 |M |11| Start 2
             Switch GND |N |12| Switch GND
             Switch GND |P |13| Switch GND
                        |R |14| SLAM Switch
              Coin Aux. |S |15|
              Self Test |T |16| Coin Switch Left
      Coin Switch Right |U |17|
                        |V |18|
                        |W |19|
                        |X |20|
                    +5V |Y |21| +5V
                    GND |Z |22| GND
                        -------

                          P19
                        _______
                  X OUT |A | 1| X GND
                  Y OUT |B | 2| Y GND
                        |C | 3| Shields
                        |D | 4| Fire
            Rotate Left |E | 5| Rotate Right
                        |F | 6| Thrust
                Red GND |H | 7| Red
              Green GND |J | 8| Green
               Blue GND |K | 9| Blue
                        |L |10|
              Audio GND |M |11| Audio 2
                        |N |12| Audio 1
                        -------


--------------------------------------------------
       SPACE DUEL CONTROL PANEL PINOUTS

           pin  color   function
           ---  ----   ----------
           1    W-Bk   Shields 2
           2    W-Bn   Rotate Left 2
           3    W-R    Rotate Right 2
           4    W-Or   Thrust 2
           5    W-Y    Fire 2
           6    W-Gn   Select LED
           7    W-Bu   Select Switch
           8    W-V    Rotate Left 1
           9    W-Gy   Rotate Right 1
           10   Bn     Thrust 1
           11   Or     Fire 1
           12   Gn     Shields 1
           13   Bu     Start LED
           14   V      Start Switch
           15          unused
           16          unused
           17          unused
           18          unused
           19          unused
           20          unused
           21   Bk     Switch GND 1
           22   Bk     Switch GND 2
           23   R      +5V
           24   Gn     GND

--------------------------------------------------
        GRAVITAR CONTROL PANEL PINOUTS

           pin  color   function
           ---  ----   ----------
           1    W-Bk   Start 2 LED
           2    Bu     Start 2 Switch
           3    W      Rotate Left
           4    O      Rotate Right
           5    Y      Thrust
           6    Gn     Fire
           7    Bu     Shields
           8    V      Start 1 LED
           9    Gy     Start 1 Switch
           10   Bk     Switch GND
           11   R      +5V
           12   Gn     GND

---------------------------------------------------------
Color Key:
    Bk     Black      Gy     Gray      V   Violet
    Bu     Blue       O      Orange    Y   Yellow
    Gn     Green      R      Red       W   White
    Bn     Brown

Colors such as "W-Bk" indicate "solid_color-stripe_color"
(in this case, a white wire with a black stripe.)

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

from Jess Askey:
If you look at the edge connector on the [Gravitar] PCB you will
see
that the +5V pins and the 'sense' pins are the same. The purpose
of
the sense pins is to provide a very low current path from the +5V
on
the PCB back to the power supply. Because the path is low
current, the
possibility of a voltage drop across the pin connection and wire
is
extremely small, whereas the potential for a voltage drop across
the
pin connection on the main +5V wire is much greater. That way, if
there
is a perfect 5.00V coming out of the Aud/Reg II board and there
is a
voltage drop of .25V on the main +5V pins, that would put 4.75V
on the
game PCB, the sense wire sends this voltage back to the Aud/RegII
board
and it compares it to a reference of +5V. Since it is low, the
Aud/Reg
II board will theoretically put out a new adjusted voltage of
5.25V so
that with the voltage drop taken into consideration, the PCB now
has
a perfect 5.00V as it should.

Sorry for the long-winded explanation. Basically, you can see if
you
look at the PCB pinouts, the symmetrical connection pattern of
the
power supply pins. You can even plug it in backwards and the way
Atari
made it, you most likely will not do any damage! Nice!

Just for clarity... the only main difference between Space Duel
and
Gravitar hardware is the existence of Linear Scaling on Gravitar
(not counting that the memory map is a bit different).

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|                              END                              |
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