Four Button Control Pad

[Chilly Willy]

Hi! Been awhile... after my dad passed away, I wound up moving, and the move gave me an ulcer... life sucks sometimes. Anyhoo, I finally got around to unpacking my 65XE and found I needed a stick. Not content with the old 2600 stick, I decided to make my own. So I looked over the threads to see what other people were doing, then decided to do it better. ?

 

I love my Sega Genesis control pads. They're the best of the old systems. And the old 3-button pads (which actually have four buttons) looked to be a great place to start. I figured that I could make B the standard trigger, A the secondary trigger most people do for 8-bit/2600 pads, and then make C the same as up. On old 8-bit systems with their single button, up was jump on a great many games, so making C the same as up means that you have a jump button right next to the trigger button. That leaves a potentiometer line open, so I hooked that to the START button. So my control pad has two triggers, a jump button, and a separate START/PAUSE button. Noice!

 

So let's get this puppy going! First, take the control pad apart. It's easy - there's just several cross head screws on the bottom. No special tool required. The PCB will look like this

 

 

 

Ho! Lucky!! It's not surface mount. Older pads are like above, and newer ones are surface mount. The procedure to convert into an Atari compatible pad is exactly the same, it's just a lot more fidgety soldering. So I really lucked out on that one. So, next we remove everything but the cable. Yes, everything.

 

Now you want to swap cable pins 5 and 7. Next, bridge IC pads 3 and 4, 6 and 7, 9 and 10, and finally 11 and 12. Solder a wire between IC pads 1 and 14. Then solder a wire from the pads that used to have the pull-up resistors connected to C and UP. Finally, solder 330 ohm pull-up resistors in place of the original pull-up resistors on A and START. The size of those resistors isn't that critical. I used 330 ohms because that what was suggested in the original A2600 two-button stick document. It could be anything between 200 and 6700 ohms. The smaller the resistance, the more power it takes, but also the quicker it will charge the potentiometer line. If you've done it all correctly, it should look like this

 

 

Note the 1/8th watt resistors. Is that okay? Hmm, P = V^2/R, so 25/330, or about 76 mW, which is about 1/13th of a watt. So, yeah, it should be fine. If you wanted to use a resistor below 270 ohm, I'd suggest going with a 1/4th watt resistor instead.

 

A quick check with the volt-ohm meter to make sure nothing is shorted and put it back together.

 

See? Not that hard. Well, maybe this might help... it's some notes I made to keep it all straight in my head...

 

And finally, here's a link to an arc of all the images, and a tiny test app that will show your new control pad in all its glory! Source is included. I assemble my A8 stuff using atasm these days, but you could also use M65.

http://www.mediafire.com/file/kkwkb99zjwu5fyp/SegaJoyPad.7z/file

[Mr Robot]

Maybe check this out

 

https://atari8bit.net/multifire-3-button-atari-joysticks/

[Chilly Willy]

That's pretty cool, but not something many people would be able to do on their own. My conversion of a Sega controller just takes a soldering iron, some solder wick, some solder, and a couple replacement resistors. But I did like the toggle switch to switch between connecting to UP vs a third trigger. It would be like if I put a switch between UP vs START. But the Sega controller has four buttons, so I didn't need to choose, I could have both UP AND a third trigger (which I made START).