So this was my absolute favorite controller back in the day. I beat Wing Commander Prophecy with it, and it's throttle was a godsend for simulators like that. Also used in for Mechwarrior 2: Mercs and a smattering of NES and SNES emulators once upon a time. They released a force feedback USB version, but it dropped the throttle and I didn't like it nearly as much.

Curiously enough, I actually bought one brand new in the box for like, $20 off Amazon recently. These things are super common despite not being made for decades. Funnily enough I still had my old driver cd for it, with a much newer version number than the one I got fresh off Amazon.

I think I've actually seen another Arduino project for one before.

Namrok wrote on 2021-04-27, 14:20:

I think I've actually seen another Arduino project for one before.

Since you mentioned it, I did some more digging and found this: https://github.com/prosper00/GRiP-duino

It's not super well-documented, but from the README it sounds like it works! There's also a Linux kernel driver for the Xterminator's protocol which has all the code for decoding its packet format, so if there are any problems with the existing Arduino code it won't require a full-on reverse engineering effort to fix them.

My ultimate dream would be to get it working with one of those tiny Arduino-clone boards that can fit in a DB-15 screw terminal, giving you a tidy plug-and-play USB -to-GrIP cable.

Do you know which pins on the game port the colours go to? I'm assuming black (Gnd?) to pin 4 (or 5,12) and red (5V?) to pin 1 (or 8,9,15)? They should be fairly easy to identify on the PCB and only leaves Green and White to sort out (2&7 or 10&14 maybe?). Unless someone else has some internal photos, then getting power to the right place is the first thing to do. A couple of photos showing the front and back of the PCB including P1 (I'm guessing that's where the cable went) and C6 would help.

Those wire colours are suspiciously USB like with the green and white, and photos like here: https://www.amazon.co.uk/Gravis-Xterminator-D … n/dp/B00004YMGV look like a single controller can have a simple USB adapter fitted. I'd guess it wouldn't work for chaining together multiple controllers.

snufkin wrote on 2021-04-27, 16:07:

Do you know which pins on the game port the colours go to? I'm assuming black (Gnd?) to pin 4 (or 5,12) and red (5V?) to pin 1 (or 8,9,15)? They should be fairly easy to identify on the PCB and only leaves Green and White to sort out (2&7 or 10&14 maybe?). Unless someone else has some internal photos, then getting power to the right place is the first thing to do. A couple of photos showing the front and back of the PCB including P1 (I'm guessing that's where the cable went) and C6 would help.

Those wire colours are suspiciously USB like with the green and white, and photos like here: https://www.amazon.co.uk/Gravis-Xterminator-D … n/dp/B00004YMGV look like a single controller can have a simple USB adapter fitted. I'd guess it wouldn't work for chaining together multiple controllers.

Here are front/back photos of the PCB, with the spot the cables were connected to pointed out with a red arrow: https://imgur.com/a/Y0NrlUy

I *did* test out the port-to-wire connectivity with a multimeter at one point, but I can't find the paper where I wrote down the results right now. From what I remember, I was able to trace all-but-one of the wires (white or green).

Ok, so I think it's possible to make a fair guess at the pinout. Looking at the upper side of the PCB, the electrolytic capacitor has its negative terminal facing the top of the board. On the underside you can see that trace going to pin 4 of P1, so is probably Gnd, so given the colour choices, probably the black wire. Equally, the +ve side of the capacitor goes through an inductor (L1) to pin 1 of P1, so is probably red (unless Gravis are being weird). In between are pin 2 & 3, which stay as a pair running down to pin 18 & 16 or U1. So possibly a balanced pair, like USB.

Taking a slightly wild leap, given the wire colours, the track routeing, and what appear to be very simple gameport->usb adapters, I'd guess that this follows USB colours, which makes pin 2 White (D-) and pin 3 Green (D+).

One things that might be interesting to try is find a USB cable you don't mind cutting open, snip a connector off of one end, then solder it on to that J1 connector, plug it in to a USB port and see what happens. Either way, you should be able to test whether any of this works without having to reassemble the whole thing. And you may want to wait a bit anyway in case anyone can take/find a photo of an intact connection.

[edit to swap J1 for P1]

snufkin wrote on 2021-04-27, 18:48:

Ok, so I think it's possible to make a fair guess at the pinout.

This is incredible, thank you so much!!! If no one's been able to confirm the wiring by this weekend I'm going to try soldering it up the way you've illustrated here, and report back with my results. Unfortunately I don't have a

One things that might be interesting to try is find a USB cable you don't mind cutting open, snip a connector off of one end, then solder it on to that J1 connector, plug it in to a USB port and see what happens.

I was curious about that. I wonder if it implements a normal USB-HID interface or whether it requires a custom driver? Regardless, it would mean I could actually test it since I don't have any computers with Gameports handy.