Re: Apple II's paddle 3 button

[mjmahon@aol.com (Michael J. Mahon)]

Dave Althoff Jr wrote:

>Stefano Priore (stefano.priore@inwind.it) wrote:
>: Michael J. Mahon <mjmahon@aol.com> wrote:
>: > Stefano Priore asked:
>
>: >>To which memory location is paddle 3's button mapped? Some sources seem
>: >>to imply that it's mapped to $c064, but according to others this switch
>: >>reads joystick #1's X axis...
>
>: > There is no "official" relationship between Paddle 3 ("GC3") and a
>: > particular pushbutton, since there are 4 paddle inputs and only
>: > 3 pushbutton inputs.
>
>: > The third pushbutton input, usually referred to as PB2 but called
>: > "pb3" on p.79 of the Reference Manual, is read at location $C063.
>
>: OK, now I see what confused me. But does this mean that Apple II's
>: hardware can't read the status of the fourth pushbutton (PB3)?
>
>There is no fourth pushbutton.  There is no pin for it on the paddle port.
>
>(speaking only of Apple ][-Apple //e.  Not so sure about the IIgs...)

That's correct--the IIgs is the only Apple II that implements PB3, and
it does it by re-purposing the cassette input flag.  PB3 is wired to
pin 9 on the IIgs internal 16-pin game port.

-michael

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