Sega 3 button controller to c64

[nivalis]

I have been working on a little project a few evenings lately, and tonight i finally got it working. It might not be the most optimal solution maybe, I would appreciate any tips on a better design.

What I have is a sega 3 button gamepad with all 3 buttons working on a c64, without modifying the controller itself.

I mapped button A to UP (for jumping), B to normal fire and C for commodore button 2 (few games use this, MYTH is one)
Easy to change though.

For use with an Amiga, the button 2 signal must be inverted (C64 needs signal HIGH to trigger btn2, Amiga expects LOW)
Can easily add a switch for that.

I'm also thinking i could add another 9-pin d-sub for port 1 and use the start button for games that require you to press space.

I made a 555 pulse generator for switching the select line, i think around 70hz and 99% duty cycle is what I have atm, seems to be working fine.

Button A is the hardest to get working, but i got it working with a flip-flop (I made it from nand-gates as thats all i had available atm)

Tested it using myth, where button C lets you chose weapon, and it works very good. Also tested a handful of other games, turrican, ghosts'n'goblins, etc, and A for jumping works fine as fa as i can tell.

Parts used:

2x 74ls04n hex inverter
2x 74ls08n quad and-gate
1x 74ls38n quad nand-gate (requires pull-up resistors, was all I had atm, probably better to use a RS flip-flop)
1x 555 timer for pulse generator to SELECT line on sega controller
100 nf capacitor for pulse generator
200k resistor for pulse generator
1k resistor for pulse generator

 

[mamejay]

What a great idea. I am sure yourself or someone else with PCB designing experience could whip up a nice small neat board for this.
I would be interested in grabbing a few if they are made available.

 

[nivalis]

That would be a possibility in the future, right now I just want to make sure its working as intended, I already did some changes to it
I am doing a stripboard version atm.

 

[mamejay]

Can you post the strip board layout??

 

[nivalis]

I havent had time to play with it much lately, but it has struck me there might be a much easier way to accomplish the same functions. The stripboard i made is a mess, and not functioning entirely correct, but maybe if i can cut down on some chips it will be easier to make a neat stripboard

 

[nivalis]

Allright, I have made some progress and I am getting quite satisfied with it. I changed the mapping, so now button A acts as commodore button 2 and Button C is jump (Commodore UP), just a personal preference.
Also added a switch, as some games on the Amiga expects button 2 to be inverted, e.g Alladin (but most games actually works as on the c64)

I added some caps too, fire button acted as autofire (not a desired feature for games like r-type , and movement left/right was somewhat jerky without them (because of how the select signal works on the sega)
I changed the frequency of the select signal as well, as the previous version wouldnt recognize 6 button joypad/stick without the mode butten held down during power on.

I also compressed it a bit (a lot?) and got rid of some logic ic, now only 3 logic ics and the 555 timer.

I made a stripboard prototype, and have tested a handful of games so far.

Banshee, R-type 1 and 2, Turrican series, Flashback, Alladin, Ruff n tumble to mention a few, takes advantage of button 2 on the Amiga
On the c64 I only tested Myth, I think there a a few more games that use button 2 (Paradroid remake?), but not tested, if anyone knows any please tell me.

I will try to etch a home-made pcb next probably. Maybe redesign it using smd components to make a smaller pcb.




- - - Updated - - -

A video playing Myth on c64. This is before I changed the mappings, so I change weapons with C and jump with A.
[video]https://www.dropbox.com/s/aog4gtj0u75o6c5/Sega-C64.mov?dl=0[/video]

 

[mamejay]

Any news on this one yet? Really want a little project to work on.

 

[nivalis]

I have very little time to tinker nowadays, but the prototype is working quite well I have plans to layout a pcb in eagle and try to etch at home, but as said, I have very little spare time to play now. I appreciate your interest, and wish i had the time to work on making a pcb layout, but it will have to wait for now.