Subject: C-64 to A2 Koala Pad Converter? (was Re: Koala Pad)
From: Rubywand <[email-masked]>
Date: Thu, 28 Aug 1997 12:30:51 +0000
Newsgroups: comp.sys.apple2

Ray writes ...

> ....  This Koala Pad has a 9 pin male connector the same
> as the male joystick port on my apple IIe.  I thought I may be able to
> get a gender changer and connect there but it doesn't sound that way.
> Is there a practical way to use this with any AppleII product?
>                                         Ray

     It appears that there is some confusion about male/female. The 
standard Apple II 9-pin Game/Joystick port has a female connector or 
socket. Standard Apple II joysticks with 9-pin DIN plugs have male 
connectors.

     Since the standard Commodore-64 9-pin DIN port is male, it looks 
like your Koala Pad (with a female plug) is intended to work on a C-64, 
VIC-20, etc. machine.

     As to whether or not the C-64 Koala Pad can be used on an Apple 
II, it looks like, probably, it can, if you can find or build an 
adaptor. This is, really, a guess. It is based upon the capabilities of 
the C-64 Game port, time constant capacitor values used in the C-64, 
and the probability that Koala Pad's makers would not wish to make 
major design changes between Apple and C-64 models.

     Although C-64 joysticks are of the simple "switcher" type which 
connect to Game port switch inputs, the C-64 Game port also includes X 
and Y analog "paddle" inputs. These are at pin 9 (X) and pin 5 (Y). The 
C-64 manual does not ever seem to specify an optimal max R value for 
the pots connected to these inputs; but, the capacitor part of the 
expected R/C circuit is 1000 pF in each case and the caps go to ground.

     In short, the C-64 "paddle" inputs look very much like the Apple 
II joystick inputs. A _try_ at an adaptor would look something like the 
following ...

To C-64 Koala Pad    To Apple II Game Port
 (9-pin male DIN)      (9-pin male DIN)

        1 ?  
        2 ?   2nd Button -> 1
        3 ?
        4 ?
        5 <-  PDL1 (Y)   -> 8
        6 <- main button -> 7
        7 <-  +5V line   -> 2  
        8 <-    GND      -> 3
        9 <-  PDL0 (X)   -> 5

     The above assumes that the C-64 Koala Pad will use C-64's "Fire 
Button" input for its main button. The second button would, then, 
connect to one of the four joystick switch inputs. (Actually, since all 
of the switch inputs, including the Fire Button, are just inputs to a 
port IC, any two may be the ones used to handle Koala Pad's buttons.)

     It should be possible to detect the button lines on the Koala Pad 
connector using an Ohm meter (on R x 100 range) with one lead connected 
to the GND pin (pin 8) and using the other lead to check pins 1, 2, 3, 
4, and 6. A button lead similar to one on an Apple II should show up as 
a 500-700 Ohm resistance.

     Again, we are dealing with guesses. If you decide to try making a 
converter, be sure to post what you discover. Good luck!

Rubywand