I would firstly like to thank all the people who
contacted me about the ANALOG issues, especially Chris Kemp. I have
not forgotten the pinball, Matthew. I will try to send you some
files soon.
ATARI WRITER
A few months back my old 400 decided to lie down
and die. I promptly bought an 800XL and continued pounding keys. For
some reason the ATARIWRITER cartridge I won from PAGE 6 (thank you
readers!) would not work with the XL. The first few lines printed
out, but after that would come line feeds corresponding to the page
feed. I was able to borrow another XL, but the same thing occurred.
This was most disconcerting and I can only guess at the cartridge
being an original and using I/O port B which is used by something
else on the XL.
Recently I have been able to lay my hands on
ATARIWRITER PLUS. All the printer problems seem to have disappeared.
I mention this problem because I am sure that many will have changed
to the XL during the clearance sale. If so, make sure you see the
printer working first before you buy the cartridge!
I have had a go at the 1029 printer and, for the
money, I found it very good. I consider it a printer crying out for
programs. By the time you read this, if I can borrow it again, I
shall have tried out PRINT SHOP with it. I also obtained a screen
dump program but have not had the time to try it out. If you are
interested please contact me.
JOYSTICK ROUTINES
This month I have included a simple program to
show a joystick in action, some of you may recognise it. The program
will display the positions of the joystick and the numbers returned
from the memory location of STICK(0) - location 632. To keep it
simple, I have used conditional statements (IF/THEN) to coincide
with the values returned. As you can see, although it is easy to
read the program, it takes up a lot of lines. In issue 10 I gave a
listing that would reduce most of the lines using Boolean algebra.
Have a look over that listing again, it was used to good effect by
Cliff Winship in issue 22. This time we will have a look at how to
do this using a simple array to store the X and Y offset - what has
to be added to X or Y for the next position.
As the joystick returns a value of up to 15, I
have set up an array of 30 (15 for the X offset and 15 for the Y
offset). The offset values are read into the array. When the program
gets a value (P) from the joystick it looks at the corresponding
point (P) in the array for the X offset and for the Y offset (P+
15). These are then added to the current value of X and Y and a new
position is plotted. The program then goes back to the beginning.
I have used a TRAP to avoid programming for wrap
around (making the dot disappear at one side and appear at the
other). When an error occurs, the TRAP sends the program to line
1000. Here the TRAP is cleared and the program is sent back to the
original X and Y positions. Note that the TRAP has to be reset. I
remembered Steve Wayne's letter and loaded the listing with REM's
(they can all be left out!).
COMING UP
In a future column I want to look at all those tid-bits
the experienced users know about but never pass on to beginners,
e.g. CONTROL-1. However, I will need some help from the 'old-time'
readers of this magazine. Knowing these things is one thing,
remembering them when writing this column is another! I want you to
send me as many as YOU can remember. You may think that you are
helping me, but you are really helping all those people who just
bought a new ATARI - remember the day when that was YOU? If I do not
receive any then I will write about something else!
A SOUND SAMPLER
To Jim Darnill who is looking for a sound sampler,
try 2-BIT SYSTEMS. Their demo's are great. Hopefully PAGE 6 will
have a review of this program in this or the next edition.
HELP! EXPERIENCED USERS
Shortly I shall he compiling as many ATARI tips as
possible. For this I shall need your help. If you know such things
as using CONTROL-1 or switching on the cassette motor to listen to
tapes then please send the details to me as soon as possible. four
input to me will help all those new readers learn about things that
we take for granted and because they are taken for granted, they are
hard to list, which is why I need your help.
Write to Mark at BAUG Software, P.O. Box 10,
Belfast, BT10 0TB
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