Genesis controller to DOS-PC Gameport cable

[kamiboy]

Anyone know whether it is feasible to connect a Genesis controller to a DOS-PC using a more or less simple custom DB15 to DB9 cable?

[Anapan]

I've heard of people connecting them to a Parallel port and using PPjoy
I think the main problem you'd have would be the fact that the Genesis controller is wired in parallel and the gameport is a serial bus.
It's worth a try to get it going with only the digital pins, but the d-pad might give you some trouble - Here's some info on interfacing with a gameport.
http://www.pages.drexel.edu/~kws23/tuto ... oyDos.html

[kamiboy]

I've heard of that utility but it is not what I am looking for. I want something to play DOS games in pure DOS.

It would have to interface with the game port on Sound Blaster cards and the like since games from that era are written just to do that.

In any regard, according to my own research doing this is very complicated. The PC gameport is obviously designed to interface with analoug Joysticks. That is why the X and Y axis pins expect an analoug signal that says something about how far the joystick has moved off of its axis, not a simple digital on or off signal saying whether left is being pressed or not.

This goes beyond my abilities.

[Anapan]

yeah, probably your best bet would be to take the logic circuits from a gravis gamepad. It wouldn't be all that complicated, and you'd have an awesome universal dos controller when you were done.

[CRTGAMER]

I've heard of that utility but it is not what I am looking for. I want something to play DOS games in pure DOS.

It would have to interface with the game port on Sound Blaster cards and the like since games from that era are written just to do that.

In any regard, according to my own research doing this is very complicated. The PC gameport is obviously designed to interface with analog Joysticks. That is why the X and Y axis pins expect an analoug signal that says something about how far the joystick has moved off of its axis, not a simple digital on or off signal saying whether left is being pressed or not.

This goes beyond my abilities.

The Gameport route can be done, just have to add the right resistors and isolate each button inside the Genesis PCB or as Anapan mentioned gutting out a PC gamepad. There are Gameport ready PC gamepads you can find at the Thrift Store, Swap Meet or even online inexpensively. Some such as that Gravis are well constructed.

Most DOS games in addition to the Gameport Joystick can also work with a Keyboard. There are many games that only work with the keyboard making this a better approach. A mod involving gutting out a PC PS/2 keyboard PCB and solder the Genesis PCB button pads to the Mame default button layout. This includes the ARROW Keys, CTRL, ALT, SPACE, LEFT SHIFT and RETURN keys which should cover most games. You can tie a small project box for the Keyboard PCB between the Genesis controller and PC connection. Use a YKey adapter to allow both the modded Genesis gamepad and a regular PS/2 keyboard to be plugged in.



I have done the Keyboard Mod with a Zaxxon Arcade stick and a set of PC gamepads to ensure 100% DOS and Windows compatibility. Using the PS/2 connection and not a USB guarantees DOS compatibility and no drivers are needed. A USB adapter can easily be plugged in if it will be used on a newer laptop.

The gameport plugs are no longer gameport, but isolated buttons connected to a keyboard PCB inside the box. You can see the NUM, CAPS and SCROLL LOCK lights lit up. I also added an ESC button on the box.

[kamiboy]

Thanks for the reply guys.

Alas, if I had a Gravis pad I would just use it to play games. I wanted to connect something I already owned without having to buy additional parts.

As for the keyboard solution, well, that is a good idea but it is not very elegant. I was hoping for something that could be fit into a DB15 connector head.

Seems the only solution that can be fit into a connector head is to build some sort of resistor circuit.

I found this site explaining that the X and Y pins off of a PC joystick report their position by way of a 0-100kohm resistance.

I don't quite understand how that works though. What does a resistance of 0 ohm on the x axis mean? That the joypad is centered on that axis? That makes no sense since a positive resistance could then not be interpreted as a pull in a specific direction, it could be either left or right.

So I guess the proper way to do it is have the rest position be about 50 kohm resistance, then a pull towards left reduces the resistance and a pull in the opposite increases it.

Am I on the right track on this one?

I suppose one could make a simple circuit that does exactly that with some off the shelve parts.

I have a bunch of resistors and some transistors at my place. I need to ask someone with a working knowledge of electronics whether that is enough to cook something up.

[CRTGAMER]

Alas, if I had a Gravis pad I would just use it to play games. I wanted to connect something I already owned without having to buy additional parts.

As for the keyboard solution, well, that is a good idea but it is not very elegant. I was hoping for something that could be fit into a DB15 connector head.

Seems the only solution that can be fit into a connector head is to build some sort of resistor circuit. So I guess the proper way to do it is have the rest position be about 50 kohm resistance, then a pull towards left reduces the resistance and a pull in the opposite increases it. Am I on the right track on this one? I suppose one could make a simple circuit that does exactly that with some off the shelve parts.

You could read the pins of a gameport joystick. See what it shows at middle and each far movement of the stick for vertical and horizontal. The resistors takes place of the two analog joystick potentiometers. The pain is getting all three variables correctly; mid position and the two maximum moved positions of the stick. Less resistance will be needed in one of the directions pushed. The Dpad would need to be set for all three variables, doubled to cover up/down and left/right.

Easiest is just buy a PC gameport gamepad, there are so many inexpensive out there.

The keyboard mod takes some work, the reward is it guarantees 100% compatibility for all DOS and Windows games that use a keyboard to play.

[kamiboy]

I wish there was a cheap source of such things where I live, but here are none. Ebay is my only choice and gravis pads cost a lot there, especially when you factor shipping, which is always what kills the deal.

Has any one ever thought of selling a tiny box where you can plug in a game controller from some system with a USB out the other end which just fires off key presses for each bottom or direction pressed?

Sounds like there might be a market for it.

[AppleQueso]

Actually people hack up old keyboards to make arcade controllers all the time. You could probably apply many of the same ideas and make one for controllers.

[CRTGAMER]

I wish there was a cheap source of such things where I live, but here are none. Ebay is my only choice and gravis pads cost a lot there, especially when you factor shipping, which is always what kills the deal.

Has any one ever thought of selling a tiny box where you can plug in a game controller from some system with a USB out the other end which just fires off key presses for each bottom or direction pressed?

Sounds like there might be a market for it.

Hit the Thrift Stores or try searching online. You can easily buy gameport controllers for under ten bucks. I found plenty in the link below.

EBay Search- http://www.ebay.com/sch/i.html?_trksid= ... d&_sacat=0

I thought you wanted to get DOS games to work? A game controller to USB adapter will not work for DOS. However, in Windows they will be picked up as a standard game controller. Playstation controller USB adapters are the most common. Any game controller can emulate a keyboard in windows using a utility program such as Joy2Key.