Controller (HKT-7700) mod with DB15

[rcboosted]

I want to tap into the DC controller PCB to get a male DB15 connector(Neo Geo controller extension cable) out, then I can connect any simple switch based joysticks like the Neo Geo AES joystick or any switch based joystick to the dreamcast using female DB15. The stock controller would act as a "host" and any button push on the joystick would essentially be extensions for the buttons in the DC controller. I assume each button press is just grounding it, I could be wrong. I found this pin out for the PCB on this site. https://www.slagcoin.com/joystick/pcb_wiring.html and actual diagram https://www.slagcoin.com/joystick/pcb_d ... agram1.jpg

The signal for direction and buttons can all be traced to a leg on the SEGA chip. (no analog direction) But I'm unsure about the triggers. If I tap into the signal pad as seen in the diagram, any time I push the button, it would be shorted to ground. I know the triggers are analog, that chip appears to be a hall-effect sensor, would this cause any issues? Perhaps I can't tap to the signal line, and it needs to be a different leg on that chip?

Has any done anything similar or have a better idea? If this works, it can open up all sorts of joystick/joypad options.