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Sega Genesis Controller To Jamma

chemdream

chemdream

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Hi all. I've searched a lot, and found a lot.

I'm trying to setup a genesis controller to use on my test station. I have the directionals working. But I can't get the buttons to work for the life of me. I would love for all 3 buttons, select and start to work!

Have any of you ever gotten this to work? I read the +5 isn't needed. Is that true?

I'm using this wire config:

1 Up
2 Down
3 Left
4 Right
5 ?
6 Button 1
7 ?
8 Ground
9 Button 2


Any ideas?
 
This is how I interfaced with a standard 3-Button-MD-Controller...

28624-md-controller-interface-png.png


Either you mod the controller to "common-ground" or you'll have to reverse the logic to get it working...

edit:
in other words: you have to bypass the multiplexer-ic (HC157).
Grab your controller, cut the traces for all the inputs, rewire them to the output-solder-pads.

Here're the places where to tap the signals:
gen_diagram1.jpg
 

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Thanks for the reply.

So, pretty much what you are saying, is remove the chips and resistors, and solder to the point's you've circled?
 
Not my picture, used one from slagcoin....

There are 9 wires which usually connect the pad to the genesis/mega drive.
You will have to isolate these pads in order to re-wire the controller for jamma.
Leave pad#1 alone, this is GND. Cut the traces for A,B,C,Start,Up,Down,Left,Right and route them to the pads. You want to have all the signals grounded when something is triggered. No need to remove the parts, but they're not used anymore.
You can cut the traces near the BLUE circles in the picture, then scratch the surface of the remaining trace and solder directly to that.
 
Cut the traces like this, ignore the 5V-Pad, leave Pad#1 intact!
Make double sure that all pads except Pad#1 are isolated from the remaining circuit,
Then just connect everything that is still connected to the blue-circle-areas directly to the remaining pads and write down your pinout!


md.jpg
 
I made a couple of adapters for mine so that I can hook up players 3 and 4 for NBA JAM TE in my 2 player JAMMA Cab without hacking up the wire in case I ever want to convert them back. Here's a thread on KLOV about this and below are some pics of what I did. There are different PCBs in the controllers, but the idea is still the same. For one of mine, I just had to follow the traces to make sure I was wiring things up fine. In the end, all of it worked the way I wanted it to.

Soldering.jpg


Adapter.jpg


HookedUp.jpg
 
Alex said:
Cut the traces like this, ignore the 5V-Pad, leave Pad#1 intact!
Make double sure that all pads except Pad#1 are isolated from the remaining circuit,
Then just connect everything that is still connected to the blue-circle-areas directly to the remaining pads and write down your pinout!


md.jpg
Click to expand...
Why do you need to cut the traces?
 
To isolate them from that IC. The first PSX wheel I modded wouldn't work until I cut the traces to isolate the button pads.
 
XianXi said:
Kinda weird since nothing is already connected. Is it just weird like that?
Click to expand...
Seems like something in the IC interferes. I had a customer mod the exact same wheel as me and he got stumped. Said the analogs worked but none of the buttons. I asked him if he cut the traces and I sent him a diagram. He said it worked as soon as he cut the traces. I'm not a very technical guy but I was able to figure that one out after a bit. :P
 
I'll just leave this here:
Saturn_to_JAMMA.JPG


2 players, six buttons, two extra shoulder buttons for stuff like coin input, no microcontrollers, only logic chips and a 555. It's a state machine wit set cycles, it cannot crash. It read controls at 120hz with the values I set on the 555 circuit. You could use higher clocks if you wanted. With that you use the controllers original, untampered. They plug in on that and you can just take them back to the Saturn and play there. No trace cutting, no lousy wires, no problem with the rubber contacts not being strong enough to bring the arcade input to 0.


I've been using one of that for over 6 years now.

Someone could make a kit of that ;)

And Saturn controllers are a lot better than 3 button original Mega Drive controllers.
 
Nice schematic, l_oliveira. I'm actually in the process of making a Saturn -> JAMMA adapter myself and ended up going for a FGW widget from Toodles to handle the conversion to common ground signals.
 
I was just thinking about using Saturn controllers for P3 and P4 for AvP/D&D on the multi-CPS2. Would hugely be interested in a kit if someone wants to make one--I assume I could just wire them up to the right places on the kick harness instead of the jamma edge and I'd be in business?
 
You don't need a fancy circuit to interface with a Sega Saturn controller. I wrote a program for a PIC16F690 that basically interfaces with a Saturn controller and and converts all the buttons into discrete logic level (common ground compatible) output.

it was half of my Sega Saturn to Xbox 360 adapter project... you can download the HEX and the source here: http://forums.xbox-scene.com/index....er-to-xbox-360/page-12?p=3546461#entry3546461

Literally, you don't need anything other than that chip and a power source. ZERO modifications to the Saturn controller you just plug in any digital controller and it works.

If someone wants to build and sell an adapter based on that, you're welcome to use my code I certainly don't have any plans to use it for anything :)
 
Last edited:
l_oliveira said:
I used logic chips because I did not want any software in it.
Click to expand...
I get that, but the PIC16F690 runs at 8MHz and there's only 20 or so lines of code in assembly so the read speed is somewhere around 30KHz :) Plus having only 1 component in the circuit makes it a lot easier to wire and more compact.
 
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