Enhanced Joystick Port

 Xav (Mark Crutch)          
 
 STe, Jaguar or Falcon
 
 

Extended Play

If you haven't got an STe, Falcon or Jaguar, then you may as well turn
over now, as Xav begins a new series about the enhanced joystick
ports.
 

If you've made it past the opening line of this article, then I'm
guessing you're the proud owner of one of the listed machines. If
you've progressed this far under the impression that your Mega STe
counts, however, then you too may as well turn over. This series is
all about a piece of hardware that you just haven't got: the enhanced
joystick port (EJP).

For the rest of you, there are a pair of EJPs on the right hand side
of your machine, just below the keyboard - unless you own a Jaguar, in
which case they are the "joypad ports" on the front. See them? Little
15 pin affairs that you might occasionally plug a joypad into, or that
harbour a connection to your Screenblaster or BlowUp. Good. Now that
we all know what we're talking about, it's time to explain exactly why
we're talking about them.

Do these inconspicuous ports really justify a whole series of
articles? Well obviously I think so, otherwise I wouldn't have agreed
to write this series, but as most of you will have only used them, if
at all, in conjunction with Jaguar joypads, you may be surprised to
discover what you can potentially plug into them:
 

 
...and a myriad of other hardware that I haven't even touched on.

Unfortunately I can't promise to cover all of these in depth. In fact,
this series is going to revolve largely around an ongoing selection of
experiments and circuit ideas, some of which might never be coaxed
into working. Having said that, I also hope it will prompt the more
adventurous amongst you into doing some experiments of your own.

What I can promise you, however, is a selection of explanations,
circuit diagrams, and sample code which should provide a foothold into
the world of the EJP, whether you're a programmer, an electronics
enthusiast, or just a games player.

Not everyone will find all the projects of interest. Indeed, many of
them are aimed primarily at Jaguar owners, or primarily at computer
owners. This isn't to say that the projects can't be used by both
groups, but rather that the necessary software support just isn't
present in the current selection of games and applications. In an
attempt to remedy this situation, however, I intend to include sample
code wherever possible, so the programmers amongst you can actually
use the hardware I'll be describing.
 

All tooled up

So you've decided you're going to leap in with both feet over the
coming months and build at least a few of the ideas I'll be covering.
Well you'll almost certainly be requiring a selection of common tools,
so to save me repeating this list in every instalment, you should beg,
borrow or otherwise obtain the following:-
 

 
Although not essential, you'll also find that some sort of continuity
tester will be very useful for checking your connections. At a pinch,
a battery and bulb will do the trick, but if you can get your hands on
a multimeter, and preferably one that buzzes when there is continuity,
you'll find life a lot easier.

Any components that you will need, unless otherwise stated, will be
available from Maplin electronics, whose catalogue is available in
larger newsagents. Where appropriate, I'll list Maplin order codes for
any parts in brackets after their description. I won't be saying much
about boxes and enclosures, though, as the exact requirements here
will depend on your own circumstances. Similarly, drills and saws will
probably be required to suit.

The last tool you may need is a C compiler, and a little understanding
of the language. This will only be required if you want to delve into
the more esoteric aspects of the EJPs, in order to use the code I'll
be including from time to time. If all you want to do is build some
hardware to use with other people's programs, this won't be necessary.
 

Coming soon...

If this seems like a long list of tools to gather and skills to learn,
then don't panic too much - the first DIY project won't be appearing
for a few issues yet. In the meantime, however, I'll be casting a
detailed eye over the inner workings of the most common EJP
attachment: the joypad.

Finally, as I've stated, this series is intended to inspire the more
intrepid hardware hackers amongst you to get a hands-on feel for the
capabilities of the EJPs. Because of this, I'd like to hear about your
successes and failures, as well as your opinions on the content and
level of the series, so if you're online feel free to mail me as
xav@compsoc.man.ac.uk.
 

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