http://img206.imageshack.us/img206/9083/dsc02845jpgwebak8.th.jpg
http://img525.imageshack.us/img525/4899/dsc02844jpgwebbw8.th.jpg
Yup, that’s it. I figured I should go find out for myself. This is the Gamestop rebranded MadCatz Microcon for Xbox360. D-pad, main 4 play buttons, guide button, start, back, and bumper buttons all use a common ground (the common line is the true electrical ground. I checked each point to make sure it was connected to the USB shield on the end.). Link to the product on the website is the same one I gave in the post above (the product ID# on the UPC sticker matches the product ID used on the website) but the price is $30, not $20.
The triggers both use electrical ground as one of the legs of the trigger potentiometers; we should be able to use a resistor or two and use just like a digital button.
This is very good news. That means that dual pcb support and piggybacking with a UPCB is child play. (well, its as difficult as it always was with any PCB, but since we dont have to deal with the matrix setup, its a shit ton easier than it was a little bit ago.)
The PCB has a ‘Rev. B’ on the silkscreen, so there is the possibility of an earlier revision that didn’t use common ground. So dont be pissed at me if you get one that is different. All I can say with certainty is the one I got uses common grounds.
Update: Well, the assembly and soldering on the pad looks a bit shoddy, but this thing is perfect for hacking. The triggers are active low, so even they can be used with a common ground setup. You have to be carefull desoldering the potentiometers the triggers; I ripped a pad off, and of course it was the important middle pad. I found a test point on the other side connected to it, but still it would have been nicer to have the pad where it was. You can leave the pot’s right where they are, and just connect the middle pin to your button. Or if you’re hardcore, you can remove the pot, and connect the high voltage leg of the pot to the middle pin with a 4.7k resistor. Connect the middle line to your button, and you’re golden.
The voltage going to the pot is like 3.8ish volts connected to my PC. I still need to test if everything works ok with 5v logic so it will piggyback a UPCB easy, but it should.