First Steps

by Mark Hutchinson


Issue 23

Sep/Oct 86

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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.


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.


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!).


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!


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.


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

AtariLister - requires Java

AtariLister - requires Java