Re: Applesoft? Comands to turn on and off annunciators in game port

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

Dan wrote:

>Hi, I am teaching a highschool electronics course adn found a bunch of
>apple IIe's stashed away in a closet.  I would like to interface these
>with some simple electronic components to help teach computer control.
> I understand that the game port is probably the most straightfoward
>way of doing this.  (I am trying to find a parralle card)  However, I
>cannot figure our how to activate the annunciator ports on the 16 pin
>DIP game port.  I am sorry if this has been beaten to death in this
>forum, but I do not have accese to an Apple referance manual at the
>currnet time.  Can this be done in applesoft, or do yo need to write
>it in assembler language.  If it can be done could someone give me
>sample commands, I understand it has to do with PEEK's and POKE's but
>I have been having some trouble ptting all the various bits of
>information I have found around the net togetehr to figure this out. 

Dan, there is no point in attempting what you describe without
an Apple II Reference Manual.  They are readily available for very
little money on eBay and are full of information which you will need
to accomplish what you want.

You will also need documentation on Applesoft BASIC, since
it is the native "interface" language of the Apple II, and you will
need an assembler, documentation, and a good 6502 assembly
language programming book as soon as you (or your students)
want to go beyond the timing limitations of BASIC.

The four annunciator outputs, one strobe output, and three
"pushbutton" inputs on the game connector are extremely
useful for control and interfacing projects.  Adding a parallel
interface, particularly one with a 6522 VIA, enormously
increases what can be done, but that can come later.

I applaud your efforts to start simply, but would urge you to
lay a foundation for progressing to more interesting work.
Introducing curious students to computer control is bound to
generate desire in some for more advanced projects.
(Come to think of it, _they_ may be the ones to find a copy
of the Reference Manual!  ;-)

One of the greatest benefits of using an Apple II for this kind
of project is that it is completely open to understanding--it is
not a "black box" that one cannot fathom and control.  And
the thing that "opens" the box is complete, accurate information
about it and its behavior.

-michael

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