undeadmechanic

I actually started a hardware build to do just this. I was able to get 100% functionality on 3 btn controllers. I could read A, B, C, and start. http://atariage.com/forums/topic/259881-sega-genesis-3-and-6-button-controller-project/ I never did finish the 6btn version, though. Life stuff. I'll get back to it one day. :/

Ugh. They won't ship to the US. :/

Where did you find that header? I haven't run across one yet. All I have found is males... :/

And here it is. The back side of the proto board is coated with plastidip to prevent shorts and to stiffen up and secure the wiring a bit. As I said earlier, I used an old 40 wire IDE cable that did not have pin 20 blocked off. I decided to go this route because I had no luck locating a female 90 degree 40 pin header. I figured even if I did find one, I was probably going to run into the same problem you did with clearance issues. It's not the best looking setup, but it works, and the cover goes on.

Sure, but it's probably not as elegant as you think... I'll take a pic of it in the drive in a bit.

Uh, maybe? I mean, it's not really complicated. Print out the schematics of the Indus, specifically the J3 connector pins, and the pinout diagrams of the 628128 and 74LS155 ICs and get started soldering wires. I used sockets for the ICs and a double row bulk header that you snap off to desired length. Just remember that everything is reversed since you're soldering on the back side of the prototype board. I can probably supply you with more detailed instructions when I get home from work tomorrow.

Well, I'm no engineer... I have built a few projects of my own design, and can read the schematics, I have just never noticed this before. I just finished building my own Sramcharger last night, tested and working. I built it on a prototype board with a 40 pin header and an old, OLD(!) 40 wire IDE cable that didn't have pin 20 plugged off. After assembly, I dunked it in plastidip, let it cure, and tucked it into the rear of the drive. I bought enough parts to build two for less than 20 bucks. If you're handy with a soldering iron, you can do the same.

I was just curious why they weren't shown. I was leaning towards an oversight, but I am unfamiliar with Eagle editor. Thanks.

Er, I meant to say that Vss and Vcc on the 74155 do not show to be connected to anything.

Trub, on your page, the 628128 version of the SRAMCharger shows Vcc and Vss not connected to anything. Is this correct?

Not quite, lol. I have some ideas regarding that. While I was playing around with it last night, I discovered that I'm still facing the same problem as before... my select pulses perfectly match the output of a real Genesis, but original 6btns refuse to respond. I have a cheap YOBO knockoff that works perfectly for some reason. This requires more investigation. So close...

Just had my eureka moment with the oscilloscope! I finally found my second lead for it and was able to monitor the select line and the UP/Z line at the same time to see exactly what was happening. This is with nothing pressed. One long low pulse gets the state of the A and Start buttons, followed by two quick low pulses. On the third low pulse, the UP line goes low as the controller acknowledges the "secret knock". Then, the select line is set high. Since nothing is pressed, the UP line goes high the instant the select line goes high. Now, this is with Z pressed. Same thing as before, but on the third low pulse, the UP line stays low when the select line goes high. It stays low until the select line is pulled low one last time to return the controller to it's normal state. THAT is the instant the controller reports the state of X/Y/Z/M! Now to bang it out.

Here is the basic diagram for 3 button controllers. The only things in this circuit are a 74LS32 OR gate, 4 diodes, and a male and female DB9 jack. This will also work with a 6 btn, but it will only be able to read it as a 3 btn. Feel free to laugh at my diagram, this is my first attempt at drawing out a circuit. I laid this out in a mental image when I built the first one. I've got to draw out the V2 interface, but I'm not done with the driver yet, so no hurry. Also, please remember that I am a mechanic with LOADS of experience with electronics (and releasing magic smoke), but I am most definitely not an engineer. I've just been tinkering with Ataris since I was about 6 years old.

Ok, here is the first version that is 100% functional with 3 btn controllers. It does not have any functions in it for 6 btn though. That's still to come. This ATR has MyDOS, the Mac/65 Source and binary, and "BTNREAD.BAS". The BASIC program just displays the button values for testing purposes. Now I've got to draw up the circuit diagrams to share. I'm getting there, guys! Genesis Controller.atr Genesis Controller Driver Source.txt

My mom made a surprise visit tonight, so didn't get very much done. I restored full 3btn function to my driver and realized that I'm an idiot in the process. No point in using PADDL4 as a register for the start button when I can use PADDL1, since it's on the same damn joystick port... :/ Cleaned up the code a bit & temporarily removed 6btn polling from the PWM output driver until I polish the 3btn function to perfection. Sadly, my AspeQt machine seems to have died this evening. Was going to post the current code until that happened. Also, I acquired an MIO and SCSI2SD since the last time I was messing with this and I absolutely love it. Soooooo much faster.