Possible to drive "output" from the joystick port?

[Cassidy Nolen]

Got a project idea in mind...using the 2600 to control something else. How feasible is it to use the joystick ports to switch hi or low on command, or simply put out a voltage via code programming/input?

 

I may be too far away from asking the right question here, just trying to think of devices like the KidVid that the 2600 can "control".

 

Cassidy

 

[Albert]

The AtariVox is an "output" device plugged into a joystick port, so I imagine what you want to do is feasible.

 

..Al

[Rybags]

Totally feasible to use joystick lines as outputs, though you're limited to just the 4 directional pins.

In theory the IO rate could be as fast as the CPU can handle but in practice you might need to interleave such processing with video generation and game logic.

[+SpiceWare]

Head over to MiniDig and download Stella Programmer's Guide. Search on SWCHA and SWACNT for the info you need.

[+SvOlli]

I've done a proof-of-concept linkcable for the 2600 using an Arduino for buffering data. This of course includes a working in- and output using a joyport. Take a look at http://atariage.com/forums/topic/197198-atari-2600-link-cable/.