Connecting your Atari 2600 Controller to your Emulation PC

[Curbfeeler]

Hello all.  This is my first post.  Eventually I intend to write a much longer post announcing the build of my MAME cocktail cabinet, but up to now can never find the time.  Instead, I thought perhaps I would start small.  I thought the forum might enjoy a tutorial on how to use your Atari 2600 controller with your cab (meant for Stella).

While the point of a MAME cab is to have controls built into the cabinet (arcade style), I enjoy playing the Atari games of my youth using the original 2600 controllers.  I agree that fashioning a solution which involves a corded controller snaking out of your cabinet may seem...well...stupid to many.  However, in this context (playing Stella on the cab) I think it's acceptable and maybe even appropriate.

So, I set about trying to figure out how to connect the 2600 controller to my Keyboard encoder....

This is really quite simple.  The first thing I did was I found the pinout for the 2600 controller.

http://www.atariage.com/2600/faq/index.html?SystemID=2600#pinouts
http://pinouts.ru/Inputs/JoystickAtari2600_pinout.shtml

The key here was finding out which was ground.  In this case, it was 08 as pictured below.

2600 pinouts:

_______________
\ o5 o4 o3 o2 o1  /
 \ o9 o8 o7 o6    /
  \___________/

I spent many years calling this an Atari plug.  But it turns out that this is nothing more than a 9 pin D-Sub connector.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=090-550

In order to complete this project you will need to find a male version of one of these connectors.  That's the good news.  This type of connector has been used in about a gillion devices.  The most common use without a doubt was as a serial port in older motherboards.  in fact, if you look in any old motherboard gathering dust, you will likely find one.

What D-sub connector you use, of course, will be determined by your skills and what you have on hand.  Most will probably not want to de-solder an old motherboard.  I happened to find the holy grail of D-sub connectors in my basement -- a "DB9 to IDC10 Serial Back Plate"

http://www.logicsupply.com/products/db9_idc10dtk

Let's say, however, that you can't find a good d-sub connector.  Worst-case scenario is you will have to use an old printer cable.  Everyone has about 8-9 old printer cables in the basement.  Why?  Because every time a printer dies they save the cable, and when they buy a replacement printer it comes with new one.

The printer cable will actually work fine.  Plug the 2600 controller all the way to the left.  You'll have a lot of unused space in your plug, but that won't hurt anything.

<aside-rant>
While we're on the topic of unused space, once you see the Atari controller plugged into that printer cable, the first fool thought that will enter your head is that you should connect the other Atari controller on the to the right side of the printer cable for some head to head action.  You should forget about this.  The entire right side of a printer cable is wasted.  They are all grounds.
http://pinouts.ru/ParallelPortsCables/Printer_pinout.shtml
</aside-rant>

So now we get down to business.  It doesn't matter what your 2600 controller is plugged into at this point, because the process is the same.  We start by cutting off the un-needed end of whatever cable you're using and stripping back the insulation.

In my case I will cut the plastic rectangle (IDC10) connector off and strip back the wires.  These are the wires that will go into my keyboard encoder.

If you're using a printer cable then you have a more complicated task.  I only have 9 wires to deal with, and I can see them and follow their paths.  But if you're using a printer cable you'll have 17 color wires and one ground wire.  That's okay; we have a method to determine which wires are needed...

In order to find out which wire is our ground, we read our pinout diagram.  Turns out that pin 8 on the Atari 2600 controller is ground.  Here is a point of confusion.  The male d-sub is a mirror image of the female.  Don't get confused into thinking pin 8 is in the same spot on the male plug.  I find that it's easiest to note pin 8 on the Atari and note which pin it connects to when I mate them.  In the case of a printer cable it's pin 16.

Also note that even if you are using a 9 pin d-sub connector, the location of the 8 pin will be opposite where it was on the controller (refer to diagram in the top right and compare it to the diagram on the top left -- http://pinouts.ru/Inputs/JoystickAtari2600_pinout.shtml)

Now to get to business....Turn your multimeter to Ohmmeter.  That's the one that has the Greek letter OMEGA.  To test that it's working touch the two tines together.   The meter should spike.

Now strip back a wire and connect it to one tine on your meter.  An alligator clip can be helpful, but I do this with my finger.  Your finger won't affect anything.  Now touch the other tine to the pin that corresponds to Atari's ground.  Hopefully first try you'll get it.  Yeah right.  If the wire doesn't match I go ahead and touch all the tines until I find the correct pin.  If that pin isn't one of the 9 that Atari will connect to, I cut it off.  Also, don't waste your time touching the tines on the bottom row on the right side (past the 5th pin).  They are all ground.

I did this and found my cable to match Atari's ground at Orange/White, but your results may vary.

Now that we have our ground wire pinpointed, things will get easier.  Now we simply plug the Atari controller into our d-sub male connector.  Next we alligator clip the ground wire to one of the tines of our meter.  We push the button on the Atari controller and hold it down while we start touching wires with the other tine.  When we get a spike, we've found the wire that will be the button wire.  Write it down and repeat for up, down, left, right.

Hint:  I've found you can save a lot of time in this phase by touching several wires at the same time (5 or 6).  If the control you're pushing isn't in that set you can go on to the next set.

Here is what I found.  I don't know if this will hold true for other cables:
Brown-white = button
Orange = left
Brown = Up
pink = right
red = down

So that's pretty much it.  Once you know the wires you can connect them to your keyboard controller and use your Atari Joystick with your cabinet.

Enjoy!