Rough Idea for multi button gamepads

[+jedimatt42]

My continuity tester won't operate a diode. But the resistence (non-beeping) mode will. However I have to be careful not to bridge the diode with my fleshy conductive self or it will read misleading results.

 

I designed the pcboard you show from the top diagram. I never thought much about it. I just trusted it.

 

OUT and IN in the middle diagram are subjective.. more or less from a programming point of view, than an electrical current point of view.

 

When I look at this diagram: ( from: http://www.unige.ch/medecine/nouspikel/ti99/keyboard.htm)

 

 

The way I read this, the connections to the 9901 for up/down/left/right and fire are all held at +5v will pull-ups. The diode in the joystick allows the current from those pull-ups to sink to LOW at the 9901 input pins when you complete the switch AND the player is selected ( the 1Y2 or 1Y3 on the 74LS156 go LOW when the respective joystick is scanned )

 

-M@

 

 

[Sinphaltimus]

So here are the final few photos.

 

The rats nest was the first joypad I tried to mod that I goofed on - will fix at another time.

The cleaner JoyPad attempt #2 is at the bottom.

 

 

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