PC Joystinck with more than 4 buttons

[Daniele - Skrauso]

HI all,
I'm reversing the circuit of a 8-button pc joypad. I read on the web that
the native joystick interface on audiocards supports 4 buttons and 4
potentiometers directly connected to the port. Now.. does anyone know how it
is possible to implement 8 buttons? On my actual circuit there are some nand
gates (used to get the turbo funcions on some buttons) and some 3-pins smd
components I suppose are transistors. The joypad is contolled by a generic
8-buttons driver under windows. Is there a sort of time-multiplexed access
for 8 buttons recognzed by the driver?


Thanx

Daniele

 

[Si Ballenger]

HI all,
I'm reversing the circuit of a 8-button pc joypad. I read on the web that
the native joystick interface on audiocards supports 4 buttons and 4
potentiometers directly connected to the port. Now.. does anyone know how it
is possible to implement 8 buttons? On my actual circuit there are some nand
gates (used to get the turbo funcions on some buttons) and some 3-pins smd
components I suppose are transistors. The joypad is contolled by a generic
8-buttons driver under windows. Is there a sort of time-multiplexed access
for 8 buttons recognzed by the driver?

Go to ebay and search for usb gameport to see a 4 port setup.
These have been used for digital input to a pc. Should be able to
get 16 buttons from this gizmo.