Colecovision controllers

[Muzer]

I bought a ColecoVision yesterday (just because one was there; I didn't buy it for any particular purpose). I've been researching a little on the controllers, and found a few things about them. Firstly, they obviously have far more buttons than pins (telephone keypad, joystick and two different fire buttons) so it needs to use some sort of encoding method.

I found a simple pinout that can probably be used if you don't want keypad support: http://www.atarimuseum.com/articles/phillyclassic/kiosks/coleco/cv14.html

I also found a circuit diagram of what the controllers look like inside:
http://www.chromesphere.com/coleco/Documents/ColecoController.jpg - however, I'm not sure if this is quite right, as I can't figure out how this would work with the previous document with the second fire button for instance.

I have gleaned from somewhere else that the console cycles one of the pins between a positive voltage and negative voltage, so the diodes then let through or don't let through the current in each case and so more keys can be detected at once. I doubt sending out negative voltages is electrically possible in the Retrode - since it's probably not, it would be best just to use that pinout on the first site and hope it works, and forget about keypad support.

[Matthias_H]

That's just about the weirdest combination of pull-up and pull-down switches I've ever seen. Won't work with Retrode, guaranteed.

[Muzer]

OK to both this and the Spectrum one - fair enough, was worth checking though!