Are you talking about pad ? Intellivision Pad or what ? ^^

[scalpel]

Here, you can see a nice pictures about pad's history

 

Scalpel

[Rev]

What a nice mess of a diagram!

[Oscar G.]

Great diagram... Thank you for sharing it. Very informative although some entries could be discussed. I don't see the Atari 2600 Trackball... was there one? I kind of remember some publicity about it included in the Centipede game.... Thanks again and cheers!

[pimpmaul69]

Great diagram... Thank you for sharing it. Very informative although some entries could be discussed. I don't see the Atari 2600 Trackball... was there one? I kind of remember some publicity about it included in the Centipede game.... Thanks again and cheers!

they were faux trackballs. not really a trackball. but yeah atari released several of them

[JohnPCAE]

I took mine apart once and the guts looked like a scaled-up ball mouse. I always wondered how they squared that with the joystick inputs.

[+DZ-Jay]

I took mine apart once and the guts looked like a scaled-up ball mouse. I always wondered how they squared that with the joystick inputs.

 

Track balls are exactly upside-down mice. The inputs are directly correlated to a 4 way joystick in that both only have 2 signals, for the x and y axes.

 

When the mouse (or trackball moves) all its doing is rolling one of two wheels: one for the x axis and the other for the y axis. Diagonal is just both wheels moving, activating both signals.

 

dZ.