Digital Joystick Adapter for Vectrex
====================================

[These adaptations can also be used for a digital trackball (suggested
by Mark Shaker)]

This one was much easier than the 5200 adapter. In fact, it's got me 
rethinking the 5200 adapter (again). 

Thanks go to #rgvc's resident tech wizard, Kevin Horton, for some preliminary 
guidance. It's not a terribly complicated device, but he saved me a bit of 
wear and tear on my own noodle. 

Materials needed:

  [2] 4052 (8-to-2 analog switch) 
  [2] 4.7 kohm resistor 
  [6] 10 kohm resistor 
  [1] 9-pin male Dsub connector (for 2600 joystick connection) 
  [1] 9-pin female Dsub connector (for Vectrex port connection) 

Cutting up a Sega controller extension cable can give you both the connectors,
and a lot more breathing room than you had with the coiled cord on the 
standard Vectrex controller. The Vectrex controller port is deeply recessed, 
and it's shaped so that the extension cable may not fit properly. I had to 
trim a bit of material off the lower corners cable's plug so it would fit. 
Works great!


Pinouts
=======


The Vectrex controller port
---------------------------

9-pin MALE D-sub connector on the console.

  1 2 3 4 5
_____________
\ o o o o o /
 \ o o o o /
  ---------
   6 7 8 9

1. /Button 1
2. /Button 2
3. /Button 3
4. /Button 4
5. Horizontal potentiometer
6. Vertical potentiometer
7. +5VDC
8. GND
9. -5VDC



Digital controller plug
-----------------------

9-pin FEMALE D-sub connector on the joystick.
 
  5 4 3 2 1
_____________
\ o o o o o /
 \ o o o o /
  ---------
   9 8 7 6

1. /North
2. /South
3. /West
4. /East
5. +5V (Sega)
6. /Button 1
7. +5V (Atari)
8. GND
9. /Button 2



4052 (8-to-2 analog switch)
---------------------------
     ________
1X0 |1  \/  16| VCC
1X2 |2      15| 2X2
 1Y |3      14| 2X1
1X3 |4      13| 2Y
1X1 |5 4052 12| 2X0
/EN |6      11| 2X3
VEE |7      10| S0
GND |8_______9| S1



Schematics
==========

Connect the +5 volts pins of the port and controller directly together
(Vectrex7 to Atari7)
 
Connect the GND pins of the port and controller directly together.
(Vectrex8 to Atari8)


Voltage Divider
---------------

The voltage divider to provide the proper voltages to the direction DAC's

     -5V (vec port pin V9)                +5V (vec port pin V7)
               |                                   |
               |                                   |
               |  4.7k     10k      10k      4.7   |
               o--/\/\--o--/\/\--o--/\/\--o--/\/\--o
                        |        |        |
                        |        |        `--high voltage (+3.4V)
                        |        `-----------mid voltage (0V)
                        `--------------------low voltage (-3.4V)



The horizontal direction Digital Analog Converter
-------------------------------------------------

     GND--+--|1  \/  16|--+5 volts
          |  |         |
          +--|2      15|---------->low voltage (-3.4 volts)
          |  |         |
          +--|3      14|---------->high voltage (+3.4 volts)
          |  |         |
          +--|4 4052 13|---------->Vectrex horizontal input (port pin V5)
          |  |         |
          +--|5      12|--GND
          |  |         |
          `--|6      11|---------->middle voltage (0 volts)
             |         |
   -5 volts--|7      10|-------+-->Atari port Left (pin A3)
             |         |       |
        GND--|8_______9|--+------->Atari port Right (pin A4)
                          |    |
                       10k< 10k<
                          <    <
                          |    |
                          +----+--+5 volts



The vertical direction Digital Analog Converter
-----------------------------------------------

     GND--+--|1  \/  16|--+5 volts
          |  |         |
          +--|2      15|---------->low voltage (-3.4 volts)
          |  |         |
          +--|3      14|---------->high voltage (+3.4 volts)
          |  |         |
          +--|4 4052 13|---------->Vectrex vertical input (port pin V6)
          |  |         |
          +--|5      12|--GND
          |  |         |
          `--|6      11|---------->middle voltage (0 volts)
             |         |
   -5 volts--|7      10|-------+-->Atari Down (pin A2)
             |         |       |
        GND--|8_______9|--+------->Atari Up (pin A1)
                          |    |
                       10k< 10k<
                          <    <
                          |    |
                          +----+--+5 volts





What about the buttons?
-----------------------

The Fire button is connected from Atari pin 6 ---- Vectrex pin 4.

In order to play Minestorm as you do Atari 2600 Asteroids (Up is Thrust, Down
is Escape), bypass the vertical circuit ...
 
Connect A1 ---- Switch ---- V3 
Connect A2 ---- Switch ---- V2


The standard stick has provision for two buttons. The Vectrex has four. What 
do you do about this? So far I don't have much of an answer. 

 -Glue some extra buttons on your favorite stick. 
 -Make do with mapping the two buttons you have to the Vectrex's #3 and #4 
 -For games that only use the west and east directions of the stick, map the 
  north and south directions to work as buttons. You can play Minestorm just 
  like you used to play 2600 Asteroids, where north is thrust and south is 
  hyperspace. 
 -Monkey up something with a Genesis pad.