1 reply to this topic

[rkenneha]

I have been planning to build an atari joystick to parallel port adapter, but I see lots of conflicting information out there:

1) The "Linux joystick parport drivers manual" says to use the data lines to power the joystick, and to connect the joystick ground to the parallel port ground.
The problem is, an Atari 2600 joystick does not USE the power line...only the ground line and 5 switch lines.
Therefore, it would seem that connecting it this way would do nothing but pull a parallel port status line low when the joystick is moved.
What makes it go high?

It would seem that you would want to connect the data lines (used to provide power) to the GROUND line of the joystick, so that it would provide a high signal to the status lines when a joystick is pressed, or no signal at all when not pressed.

2) This circuit below uses pull-up resistors:


My question here is...would this circuit make a status line go low when the joystick is moved, and high when not moved, correct?
Also, are pull-up resistors overkill on computers made in the last 10 years?

Thanks for all your help!

[GroovyBee]

rkenneha, on Sat Jan 7, 2012 9:48 PM, said:

My question here is...would this circuit make a status line go low when the joystick is moved, and high when not moved, correct?

Correct!

Quote

Also, are pull-up resistors overkill on computers made in the last 10 years?

Since the 2600 joystick just contains switches the pull-ups are needed (other sticks may be more complex). The PC parallel port may have internal pull-ups but they will most likely be very weak.