The independent MONTHLY magazine for T/S1000.ZX81 users

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Software, hardware & books reviewe

Umax Computers Ltd. end Sinclair Research Ltd. do not sponsor nor take responsibility for this magazines content. Permission hatfWn §rai

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Timex announces a new personal printer.

Just for the record.

Now Timex brings you a printer to go with your Timex Sinclair 1000 (M or Sinclair ZX81.

The new Timex Sinclair 2040.

32 columns wide. Two lines per second. With full graphics and text capa¬ bility based on a dot matrix print mechanism.

The price: just $99.95.

The TS 2040 operates silently in two different modes:

□ Full-screen printing with single-key copy command.

□ Program-controlled printing mode allowing for custom control of the printing format.

A printer that can give you a permanent record of your computer programming at a very affordable price.

Just what you'd expect from Timex.

TIMEX COMPUTERS

For more information, circle 1 on Header Service Card.

C Timex Computer Corporation 1983

1

President

Terry Cartwright

Editor-in-chief John Sterlicchi

Managing Editor

Joseph Gladstone

Art director

Vladyana Krykorka

Clive (urns computers to cosh, page 66

Education myths exploded, page 22

Production editor

Bill Gladstone

Art assistants

Andres Hannach Don Kletke Gwen Egan

Technical advisors

Robert Fraser Igor Nowikow Tom Perrone

Editorial assistant

Becky Ashwell

Chairman Richard Hease

Timex Sinclair User is published monthly by ECC Publications Inc. in conjunction with C.W.

Co mmunic ations/I nc ,

If you would like to contribute to Timex Sinclair User, please send programs, articles or ideas for hardware projects to:

Timex Sinclair User 49 LaSalle Avenue Buffalo, N.Y. 14214 Programs should be on cassette and articles should be typed. If you wish your material returned, enclose a stamped, self-addressed envelope.

We pay $20 for each program published and $100 per 1000 words for each article used.

© Copyright 1983 Timex Sinclair User ISSN 0737-0881 Typesetting by I nternationaJ T y peset ti ng Printers

Clark Franklin Kingston Press Advertising manager

Bill York Hajar Associates (617) 444-3946

2

TIMEXPECTATIONS _ 3

Why doesn’t Timex provide more a/ier-sole support?

LETTERS _ 0

"The T/S1000 is more than a toy"

SOFTWARE _ _ _ 7

Space and adventure games and an assembler program reviewed

HARDWARE _ 12

In search of a golden memory

NEWS - _ 14

T/S10GG and ZX81 combined sales over 1,6 million; Clive Sinclair awarded; and

more

SPECIAL OFFER , _ . _ 15

Save 30% from the price of The 1983 Sinclair User Annual

COVER; THE GREAT CONNECTICUT KIT-BUILDING EXPERIMENT _ 1 6

Teacher Chris Baldwin helped 28 kids build computers from kits

EDUCATION _ __ _ _ : _ 22

Charles Durang explodes same old myths about computers in the classroom

FOCUS: CHESS SOFTWARE _ _ _ __ _ 28

Check our guide to chess programs before you make a move

HOW TO PROGRAM 30

Part two of John Gilbert s Jive-part senes

PROGRAM PRINTOUT 33

Bowhng, Alien Lure, Laser Cannon and other great new games

HINTS & TIPS _ I _ 42

Michael K. Barnett explains how to start using TfS graphics

PROJECT; EPROM BLOWER 46

Complete plans to build your own Erasable, Programmable ROM

USER GROUPS — - - 56

Is your group included in our notional listing?

STARTING OUT 61

What to do once your TISiOOO,ZX8i is home from the store

U.K- WINDOW — _ _ _ 63

Sinclair users in Britain eagerly await two new expansion systems

PROFILE: CLIVE SINCLAIR - _ 66

A glimpse of the man who made computers accessible to nearly everyone

BOOKS _ - _ 68

A kids book that will dehght beginners of alt ages; all about ROMs; and more

CONTEST 70

Win $20 for a clever, different, strange or unusual program

BULLETIN BOARD 71

New product information and upcoming events

•Inside a T/S1000 computer camp! •Sneak preview of the T/S2000!

and much more!

T/S1000,ZX81 users wait in vain for important support

services

Timex needs higher profile

WELCOME to our second issue. Your response to our first was overwhelming and really gratifying. From all of us on this side of Timex Sinclair User to all of you, “Thanks".

Our contest editor is screaming for more help to deal with all the great games that are pouring in. In case this is your first look at us, last month we started the first in our series of contests. It required that you write a 41 great* * ac¬ tion game, but use only 2K of memory. The winners will receive a contract to have their programs published and

sold nationally. Then they can rake in all those lovely royal¬ ty checks. The contest doesn't officially close until June 10, so if you haven’t entered yet, it’s still not too late. For details of our latest contest, flip to page 70. This one, we’re sure, will challenge your imagination and skill.

Still on the subject of your input, the eight pages of Pro¬ gram Printouts that appear in every issue are also supplied by you the readers. For any that we use, we pay $20. We look for interesting and different programs. Programs that we feel will be enjoyed by the readers that use them. You’ll see one of the programs this month is by an eleven-year-old and another by a fifteen-year-old. And finally on your let¬ ters to us> may I remind you that we like to share your ideas, hints and problems. So many readers asked about graphics on the T/S1000,ZX81, that our Hints and Tips column this month is devoted entirely to that aspect of programming.

Timex Sinclair User was at the West Coast Fatre in San Francisco (see the news item on page 14). While it was a great fair, we were stunned by the fact that Timex had ab¬ solutely no presence there at all: not a hospitality suite, not a booth, not a table, not even a speaker! It is our opinion that at a personal computer show which attracted 50,000 spectators (each willing to pay $15) the company that has sold more personal computers than any other in North America has a need , * . no, an obligation to be there. An obligation to support all those who chose the Timex Sinclair computer as their personal choice. It would not have had to be a large, elaborate affair, but it certainly

would have made us feel better if we could have had an identification point with Timex there.

It is important that Timex provide owners with visible support, if for no other reason than to show they consider those owners important. There is a feeling in the market place that Timex Sinclair computers are not serious machines; that they are toys; that they are not capable of do¬ ing interesting and involved work, T/S,ZX owners know this is not true. Anyone who has used the machine for a while realizes this is not true. It would not only help build a better image for the machine if Timex were at personal computer shows, but it would also make those people who own one now feel like they belong to a personal computer fraternity.

Any person who buys a T/SlOQQ is a potential purchaser of a larger machine. The Japanese have been threatening to flood the $100, $200 and $300 price ranges with a whole set of new machines. If we can judge by how the Japanese have entered markets in the past, then we can expect these new imports to arrive with great fanfare and much TV hooplah! They are sure to be serious competitors to Timex Sinclair, What better way for Timex to insure its place in the market than to maintain a high profile with current owners and keep potential owners thinking T/S? User loyalty can only

CTATIONS

be developed when users feel that both individually and as a group they are seen to be important to Timex.

it makes good sense (and dollars) for both now and the future that Timex become involved through fairs, shows and user groups with owners. Each owner is a potential se¬ cond buyer, either of a Timex Sinclair machine or another make. Each owner is a salesperson for Timex Sinclair, either positively or negatively. Each owner has spent money with Timex Sinclair and deserves after-sale support.

Timex has a good reputation! The T/S 1000 is a good machine! We’re certain that the next computers from Timex will be equally as good, Timex Sinclair User wants to support Timex Sinclair computers. So, come on Timex, help us say great things about you!

TIMEX SINCLAIR USER /une I9fl3

3

SYNTAX

Serving Timex-Sinclair Personal Computers

A PUBLICATION OF THE HARVARD GROUP

ISSN 0273*2696

SYNTAX is a monthly newsletter exclusively for ZX80/ 81/TS1000 owners. We bring you news, reviews and ap¬ plications for your computer, plus technical notes for circuit-builders. SYNTAX also provides a forum for thousands of users to share advice and problems about programs and vendors. We bring you timely updates about new hardware, software and books. And we cover ufl the Sinclair- technology computers, including the new TS1000.

At SYNTAX we emphasize practicality. You can apply our suggestions even if you aren't sure at first why they work, because we give you complete instructions. Text is clear and easy to understand. SYNTAX readers already know about:

• An automatic phone-dialer they can put together in a few hours

• Syntactic Sums™ to check input for errors

• Programs to explore computer memory

• How to build external additional RAM

• How to add an 8212 I/O chip to control external devices from their computers

And SYNTAX readers like what they get every month. Subscribers know they can depend on us.

After receiving on/y three issues of SYNTAX, I find that I anxiously await the next . . . keep up the good work!

Martin Irons Goshen, NY

Congratulations on the brass -tacks, down-to- earth approach of your newsletter. Til be look¬ ing forward to future issues ,

Otis Imboden Washington, DC

Many readers get their first issue and immediately order the back issues— more proof that they like what they see.

You can see what's special about our publication. We work hard to bring you a quality newsletter. We strive to print useful programs of above-average accuracy. As any computer magazine editor can tell you, program listing ac¬ curacy is tough to achieve, but we boost our average with every issue. We test each program to make sure it works, it fits in the designated RAM, and it runs when you follow the directions. We print program listings in screen-image format to make it easier for you (it's sure not easier for us!) to enter program accurately. We invented Syntactic Sum™ as an additional aid for you in getting error-free programs. With your subscription you also get access to thousands of other readers, and our staff experts are available by phone to answer your questions or help you solve problems with your machine.

SYNTAX readers get every month:

• Latest news of Z80 hardware and software

• Programs to organize information, calculate, entertain, or instruct

• Do-it-yourself additions

• Clear explanations for beginners

To share the benefits of SYNTAX, just indicate your choices on the order coupon and return it with your choice of payment in U.S. funds. (Please note that addi¬ tional postage is required for delivery outside North America.)

We are so sure you’ll find SYNTAX useful that we promise to refund your entire subscription fee if you aren’t satisfied. An unconditional guarantee— you can’t lose.

Join the others who stretch the ZX/TS to the utmost. Act now— as soon as we receive your coupon with pay¬ ment ? your first issue will be on its way. For faster service, phone your credit card order to 617/456-3661. Don’t miss SYNTAX!

TSU583

Fill out the coupon below and mail it to: SYNTAX, SQ, RD2 Box 457, Harvard, MA 01451 L My check is enclosed. □ Please charge my □ VISA YES! Please send me:

□ The Combination (12 issues of SYNTAX and 4 issues

Make checks payable to: SYNTAX ZX80. Inc,

Diner's Club □ American Express □ Mastercard □ Carte Blanche account

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of SQ) . . . . $39

The Catch-up (SYNTAX Jan 82-Dec. 83, 4 issues of SQ,

plus 1 binder . . . $77

Exp. date _ Bank number (MC only) _ Th* Work* {SYNTAX Nov 80-Nov. 83, 4 issues of SQ.

plus 2 binders, a 50% savings) . $97

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Adless D 1 Premier ksue of SQ . . . $4.95

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Day phone ( ) _ — - Evening phone ( ) - __ These offers expire 31 Jul 83-SUBSCRIBE NOW

□ This is a renewal My subscription number is: _ _

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SYNTAX QUARTERLY

by The Harvard Group

Increase Your Computer's Utility With Our Help

You own a powerful computer, capable of sorting, analyzing, calculating, displaying and manipulating data as well as measuring and controlling. Despite its small size, your computer will help you learn, analyze your business, keep your records or your schedule, dial your phone, send messages, or talk to other computers. To control the power available to you, you'll need hard¬ ware and software to use with your machine. Although you can buy many of these products— and well tell you about them— some you must create or modify for your¬ self. SQ will provide you with the complete information to let you use your programming or tinkering time efficiently.

Our experts also bring you SYNTAX, the newsletter, for up-to-date, concise information* You need news and new product announcements quickly* And SYNTAX packs a lot of information into its brief, time-saving format*

But we recognized your need for material too long to fit in SYNTAX. Syntax Quarterly fulfills that special need. In-depth, extensive, detailed information— that's what SQ's all about* Long programs, big construction articles, and detailed directions help you use your computer to Its fullest while Learning.

SQ gives you tested, accurate information that you can depend on. We test, we build, we check everything that goes into SQ. Our staff experts work for you; it's as though your full-time staff prepared a report for you every quarter.

At SQ, we specialize in your machine— Timex-Sinclair technology. Our programs and projects work, and, because we test each one before we publish it, they work on your machine. All the information in SQ can work for you.

But, to capture these benefits — free software, free plans for hardware, free instruction— you must subscribe. Use the coupon to tell us how to help you best* Or call; we understand people in a hurry. SQ

100 LET R*=*

£00 LET B* = *

250 LET Ct = ‘«

300 print

4-00 PRINT BL6$

500 PRINT B*( TO 7>,B*

600 PRINT B$( TO ?)#B$

700 PRINT R$ Bt

800 PRINT " TO J,B*

900 PRINT " TO > - B*

1000 PRINT B*,B*

1100 PRINT R*,RS 1200 PRINT RT ?,22;C*

1300 PRINT RT 9#24jC*

1400 FOR 1=0 TO 24-8

1450 IF X>8B AND I < 128 THEN GOTO lt?00

1500 PRINT CHRS I;

1600 NEXT I

1700 PRINT RT 10 ,0J ** UE SPERK Y OUR LANGUAGE

SYNTACTIC SUH: 22174, SK ROM

UE SPERK YOUR LANGUAGE 0123

45S78GABCDEFGH IJKLNNOPORSTUUUXYZ RN DINKEY! - - - “

_ TQR ^nnrvF noi

SIN COS TRN R5N RCS RTN LN EXP . INT SQR SGN RBS PEEK USR STR$ CH R$ NOT OR RND < = > = <> THEN TO I

STEP LPRINT LLIST STOP SLOU ERST NEU SCROLL CONT DIM REH FOR GOT I O GOSUB INPUT LORD LIST LET PRUsI E NEXT POKE PRINT PLOT RUN SAVE

For more in/ormolion* circle 2 on Reader Service Cord.

617/456-3661

617/456-3661

Letters

LENDING AN EAR

I purchased the Timex Sinclair to see if a 60-year-old retired gent could learn computer programm¬ ing, 1 do have problems finding books that do more than teach one to input programs and play games. I have purchased five books on the T/S1000 and ZX81 and have yet to find an adequate explanation of PEEK and POKE. Most of the com¬ puter magazines cater to "far out” programming . . . very little is published in the form of a course to take the beginner through.

Thanks for listening.

Fred Kujawa

You are in luck, Fred.Starting in our premier issue '(May 1983), we are presenting a course in programming written by John Gilbert. Take a PEEK at it, POKE around it, and be/ore you know it, you’ll be using those /unctions with the best of them.

KEEPING THE FAITH

I would like to say that ifs about time someone believed the T/S1000 is more than a toy — I am personal¬ ly sold on it After Tve made all the additions to it (keyboard, 64K RAM pack, printer, etc.) I’d be willing to bet the T/S1000 will match any of those others!

I worked on an Apple in pro¬ gramming school, but bought the T/S1000 because 1 can bring it up to that level for less dollars. I am real¬ ly happy with it.

I just wanted to thank you for having faith in the Timex Sinclair computers, because I sure do!

David Brehm

We agree, David, and so do over a million other computer enthusiasts. Let us know what new ideas you come up with for your machine.

COMPLAINT

DEPARTMENT

I am an owner of a T/S100Q but it doesn't work. ! asked Sinclair for some information on how to fix it and all I got was a bunch of nothing.

Thank you.

Roger Odan

Roger, you are saying what a great number of people have said fsee our interview with Dan Ross, May, 1933J. We have sent your letter on to Timex. Let us know what happens.

0/0

Timex Sinclair User welcomes reader's comments, compliments, queries and complaints. Letters should be addressed to: The Editor, Timex Sinclair User, 49 La Salle Avenue, Buffalo, N.Y. 14214. Please include your full name and address when writing.

MI

VATION "WHERE ideas come to life’

16529 LAKESHORE ROAD C L E VE L A N D, Wl SCO N SI N 53015 PH. (414) 693 - 806 2

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• RAISED DEPRESSABLE KEY AREAS - FEEL MOVEMENT $9.95 •STANDARD TYPEWRITTER KEY SIZE

•EASY CUSTOMER ATTACHMENT - OVERLAYS PRESENT KEYBOARD OF THE TIMEX 1000 AND SINCLAIR ZX-81 HOME COMPUTERS

CONSULT YOUR LOCAL RETAIL STORE

For further information or mailorder via M.C. or Visa direct inquiry to InnovationCo.Dept . U

6 For more in/ormatjon, cirde 3 on Header Service Card. TIMEX SINCLAIR USER June 1963

This month we review space and adventure games and an assembler that lets you program in machine language

Push-button

Wars

Shoot Your Way T^H| Safety

Description: Combat Flight casts you as the com mander of a fighter ship, flying through moun¬ tainous terrain shooting at alien ships. Seven types of alien ships fly by. Points scored depend on the of alien you hit wit* lasers. A player lives per game.

After the game, the top five scores are displayed with the name of the player. If you score in the top five you add your name to the list.

Evaluation: This is good action game. The speed of lasers is fast and the response time of the controls '

■ - ; •

..

alien

Fhgnt mountain

must

good

graphics and fast action. This games pack is a good buy for those limited to 2K of memory. (Circle 41* on 1 ' e

language to scroll stats right to left across the1 screen. The playeT scores points by moving a base in front of the stars.

Evaluation: The major problem with Starblaster is the instructions. The infor¬ mation with the games gives the wrong controls for movement. Also, the in¬ structions do not dearly tell the player how to score points.

The other five games of this package are all of a

Description; in Galactic Invaders, sevdn alien crafts

fly randomly around the screen, and fire at your laser base. The base can withstand seven hits before it is destroyed. After all seven crafts are destroyed, seven more appear and move at a higher speed * The player scores one point for each craft shot down.

Evaluation: Although this may sound like a standard

g too high Hihtp aliejj'fe longing ships

ght is a good similar

son the

Us

Jpeed makes , ihia >a gwd game. The player is given an initial choice of speeds from 1 to 100, When i played; speed fj| was too ^ slow and lOpwas toa fast. At speed 50,. I destroyed 53 enemy crafts.

■ One annoying feature of /• this game is that the alien crafts often land on the '. ground for long periods of tirne. When this happened, J felt obliged ..to ram the craft with my laser base. Galactic Invader works in 16K and is distributed by Sams. It is a simple, fast ac¬ tion game that can be en¬ joyed by all ages. Definitely a must for the video game connoisseur. (Circle 42 on reader service card,)

Rating: 8

market. I found the game a little too repetitive in its ac¬ tion and would not want to play it often. Distributor: Melbourne House Ltd, Memory: 16K.

Rating: 7,

4444444

Fast Action

In 2K

^Inscription: In TS Destroyer, you fly in the

center of the screen, and ob- jets fly toward ypu from the left; you must dodge or shoot them. At the same time, another spaceship is flyjng up and down to your k right, taking shots at you.

fn Space Raid, you con¬ trol a gun that moves horizontally across the bot¬ tom of the screen. When a spaceship appears at the top of the screen with an alien inside, you must shoot <a ' hole through the spaceship and hit the alien in the left foot before a laser beam from the ship hits you.

Evaluation: I was very surprised by the high quali¬ fy of these two games. Pro¬ grammed in machine language, they have the speed and excitement found in larger 16K games.

The speed of movement in TS Destroyer is very im¬ pressive. Playing this game,

I was so busy trying to dodge objects from the left that I failed to see the ship at the right shoot me in the back.

The Space Raid game is very similar to invasion Force. The computer graphic of the alien stan¬ ding in the spaceship is well

TIMEX SINCLAIR USER June 1983

7

NOW ATS1000/ZX81

PUSH-BUTTON

KEYBOARD

FOR UNDER $20.00

At last there’s a really cheap but efficient way of ironing out theTS1000/ZX81’s only real bug: its keyboard. The Filesixty Buttonset offers

■ A full -travel calculator- type moving keyboard for only $19.50.

■ Installed in seconds. The peel off adhesive backing means you just register into position and press.

■ No messy labels, dismantling or soldering.

■ 3 groups of colour keys to pick out shift, numerals and newline.

■ Precision moulded in ABS to match your TS1000/ZX81, with contrasting legends for maximum legibility.

Orders to Filesixty Ltd., 25 Chippenham Mews, London W9 2AN, England .Tel: 01-289 3059. Telex: 268 048 EXTLDN G 4087.

I _ /

fonoQ •

1. Make sure the original key boar d is clean and check that all the keys function.

2 The Buttonset is held in place by sett adhesive pads.

3. So all you do is remove the protective backing.

Ion □□□□□□□□ r r : □ □ TT:: □ nTT

□ □ □□ i □ □ □ □

4 And place it centrally on your IS 1000 ZX81

Cheques/money orders made payable to Filesixty Ltd “I

Please send me _ _ _ (qty.) Buttonset(s) j

I at $19.50 each (inclusive of postage & packaging).

Total $ _ BLOCK CAPITALS '

Address

| OLCHC _ _ _ _ _ _ _ C|

|_zn _ FILESjXI_Yj

For more Information, circle 3 on Reader Service Card*

done. The descending laser beam from the ship is challenging to avoid.

Neither of these games prints a score* Usually I like to see a score after I’ve been shot, hut in these games, it didn’t matter. For 2K game players, this tape is a must. The distributor is Softsync, (Circle 43 on reader service card*)

Rating: 9

*******

A-maze-ing 3-D overview

Description: Labyrinth is a game sold by Mindware that creates a maze which the player must go through* At the start of the game, the player must choose the width and height of the maze. Before entering the maze, the player is given the option of seeing it first This gives the player plenty of time to plan a route through the maze.

The player is shown an image representing his view of the maze showing door¬ ways and corridors in three dimensions. Movement through the maze is done by four direction keys. At any point the player can give up and see a full view of the maze. The computer will show the path that was taken by the player

Evaluation: Labyrinth is an interesting game because the player sees such a small portion of the maze. The three- dimensional graphics showing the passageways are adequately handled with the T/S1OO0,ZX81 graphics* The game is quite difficult the first couple of times. With practice, however, the passageways are easier to recognize and movement through the maze is much simpler. This is an interesting game but not a classic! (Circle 44 on reader service card)*

Rating: 7,

More Missile Madness

Description: A missile launcher moves up and down on the left side of the screen in the program call¬ ed Missile Launcher* You fire missiles at ammunition dumps on the right side of

the screen. The player gets 25 shots and scores points for hitting the ammunition. Bonus points are scored for destroying an entire am¬ munition dump.

Evaluation: Shooting at targets is a popular concept in games but, to be most ef¬ fective, any such game re¬ quires an opposition that

Assembler offers

Description: Machine language programming is very slow and tedious without using an assembler program. International Publishing and Software sells ZX Assembler, a pro¬ gram that allows you to enter and edit machine language using mnemonics.

ZX Assembler occupies 7K and is located at the top of memory. It stores the machine language in a REM statement at the start of the Basic program and the assembly language in a second REM statement. An easy-to-follow 26-page manual comes with the pro¬ gram, describing its use in detail.

Editing functions allow you to insert and delete characters and lines. Numbers can be entered in decimal or hexadecimal. Mnemonics can be entered very quickly because the in¬ put response time is fast.

The program also con¬ tains a monitor which has many useful functions. From the monitor, one can run a machine code routine for testing, inspect and modify registers, search for numbers, and display the HEX contents of memory.

Evaluation: Its high speed makes machine language very attractive to serious programmers. Ex¬ ecution speed of instruc¬ tions is far superior to Basic instructions. Programming in machine language is much more difficult than Basic but programs such as ZX Assembler offer the pro¬ grammer valuable aid.

Without an assembler, programmers must POKE into memory the decimal code for each instruction. Editing in this manner becomes very difficult. ZX Assembler contains all the functions necessary for easy machine language programming.

The major drawback with ZX Assembler is its location in memory. It uses 7K of memory, limiting the size of the basic program. Because it is not relocatable, its position limits programmers with greater memory to 16K.

ZX Assembler is a very useful tool for beginners or professionals. A beginner with a good book on Z80 machine language will find this program easy to use. (Circle 45 on reader service card.) Rating: 8

TIMEX SINCLAIR USER June 1903

shoots back. Missile Laun¬ cher, programmed entirely in Basic, is too simple and slow.

The player controls only the firing of missiles. This requires the player to judge when the row of the missile launcher equals the row of an ammunition dump. This 16K game, distributed by Intercomputer, did not hold the interest of this reviewer for very long, so I played it only a couple of times. (Cir¬ cle 46 on reader service card.)

Rating: 5

*******

Defend your planet

Description: You are in charge of a missile launcher and must save Earth from invading spaceships. With 15 rockets, you must choose a velocity to shoot down the invaders. The direction of each rocket is determined by the velocity you choose for it.

If that sounds like an ex¬ citing game, then you would probably like Galac¬ tic Invasion, sold by Inter¬ national Computers Ltd, This is one in a set of six 16K programs on one tape. Also on the tape are three action games, a solitaire game and a drawing pro¬ gram.

Evaluation: This form of Galactic Invasion is very simple in graphics and design. The alien invaders are represented by 35 plot¬ ted points, and a message at the top tells you how many spaceships are left. This game may be adequate for children but most adults will find it slow.

The five programs with Galactic Invasion are also slow and simple. This tape is not recommended to those who like action. (Cir¬ cle 47 on reader service card.)

Rating: 5 0/0

9

NOW YOU CAN HAVE ALL THE ANSWERS

With the most complete Sinclair software library available.

30 PROGRAMS FOR THE SINCLAIR

ZX81

a°o*

Tt<£

Ofi

TH(

? Ur

TiMb

**6

*T'

’OQo

‘yoe

Th

Its friendly style i$ poiniess reading analogies help make this longuag This introduction is a must/' Now o

only $14.95

NOT ONLY 30 PROGRAM

is a collection of programs for tl ZXBVTSIOOa Not only Battle;

Blackjack, Wall Breaker, Mi IK Draughts, but also each programming hints, spate PEEK and POKE exploi ZX Computing said "Tl tan be crammed into Si Now available for only f

THE COMPLETE TIME]

ZX81 ROM Oisassembl

D r. Logan a n d Dr. F ran lc O' Haro all routines in the ROM ond comment on _ _ _

This book is a must for the experienced programmer L Qrdinateur Individual (the leading French personal computing magazine) said- 'Dr. Ian lagan has disassembled the 8K monitor program at the 2X81 / TS1000- For those who want to write programs in machine language, it Is PART A which is the more interesting, because it contains the majority of BASIC commands, while Part B is far more technical, comprising essentially of the ZX81 /TSJQQtfs {looting point calculator, In conjunction with Understanding Tour ZX8J ROM this book allows anyone well

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MACHINE LANGUAGE PROGRAMMING MADE SIMPLE

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In search of a golden memory

THE MOST important hardware device you can add to your computer is a memory unit. In this article we analyse three memory units for design, flexibility, durability and cost: the Memopak 16K, the Sinclair !6K RAM and the Panda 10K.

These connect to the T/ SI 000 via the expansion port at the rear of the com¬ puter. The design of the unit is very important because it must fit tightly to the computer* If the fit is loose, programs may be lost easily by any movement* This can be very annoying when you are trying to change the tape recorder leads to save a program. We have lost many programs this way*

From the pictures, you can see that the Memopak unit stretches right across the length of the computer* The unit comes with velcro tabs to help make the con* nection firmer* We have also used tape and elastic bands for the same purpose*

The Sinclair RAM is a smaller unit* It does not fit to the back of the computer as well as the Memopak. We have had great difficul¬ ty inventing ways to pre¬ vent this unit from wob¬ bling*

The Panda RAM is built similarly to the Sinclair RAM but its fit on the ex* pension bus is much tighter* We used this unit extensively for two weeks and found no problem with its design.

For design, we feel the best unit is the Memopak* Its structure is best suited

Reviewer Bob Fraser tests three 16K units and finds each falls short of perfection

0

When the lights go out . . .

THE Cramic*01 is a low- power, battery*backup RAM, It uses up-to-date technology such as lithium batteries to maintain your RAM's contents even when the power is disconnected. It is ideal for keeping large, often used programs, machine code routines or

programs you are working on without the bother of having to load them from cassette each time. This unit can be used in c on j unc¬ tion with another RAM pack and either one can be selected for use by a switch on the C ramie-81. If you happen to wander off For ten years and then return to your machine, chances are the Cramic-81 will still be working and remember where you left off.

For more information, circle reader service number 51 .

for the T/S100Q* We tike its appearance best, although the polar bear on the Panda is a nice touch* The second category we have defined is flexibility. A memory unit must allow ex¬ ternal devices such as printers easy access to the expansion bus. All three memory units allow this but the Memopak has a slight advantage because it also has an edge connector behind it, allowing a printer to be attached in front or

behind it.

The third category rating memory units is durability. How long will it work? We have used many Sinclair and Memopak memory units and can rate them fairly. The Panda has been only tested for a two week period, so its durabili¬ ty is still questionable*

When we first began us¬ ing Sinclair computers, we

used the •- — * *•*'

Sinclair RAM.

After much use, they began getting warm easily and fre¬ quently lost programs. We tried many types of memory units, finding most of them to be unreliable, until we found the Memopak.

The Memopak lasts much longer than the Sinclair RAM* For people with larger memory needs, Memotech also sells 32K and 64K Memopaks* They are of equal quality.

The table shows our rating of the memory units discussed here. We have not rated the Panda for durability after only two weeks of testing, but we will say it hasn't yet caused a single problem. (Stonechip Electronics, a British firm, is currently looking for an American distributor for ZX- Panda, which sells for about £20 in Britain.)

e/e

12

1

TIMEX SINCLAIR USER

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Use your phone to connect your "LITTLE" computer to the "LARGEST" computer networks in the world. With BYTE- BACK's MD-1 MODEM connected ell you do is dial a phone number (usually local), press a few keys and watch the data appear on your TV screen. (Software is included) This

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* A comprehensive manual is included that has complete application details,

* More than one BB-1 can he used at a time.

$139.9S ASSEMBLED & TESTED

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With

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The 0-8K area is available. You can execute a copy routine (provided) to copy the TIM EX ROM into the 0-8K area of RAM then flip a switch and you have your operating system in RAM. You can modify it and create your own customized operating system. Full details, examples & programs included.

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M

Clive sells 1.6 computers . . .

. . . and snags award

Sinclair Research has claimed to be the first com¬ pany to sell more than one million home computers.

Since it began selling the 2X80 three years ago it has sold 130,000 ZX8Gs, 750,000 ZX81s and 200,000 Spec- trums, an upgraded version of which is to appear soon in North America as the rr/S2000. And these figures

CLfVE SINCLAIR: neither young nor □ businessman

No Faire for Timex

Fifty thousand people agreed that the 8th West Coast Computer Faire, held in San Francisco From March 18 to March 20, was fantastic. It boasted 500 dif¬ ferent exhibitors ranging from the small single-booth entrepreneur selling tapes and books to the “big guns11 like Apple, Commodore and I.B.M. No, we didn't forget to mention Timex, they just didn't bother showing up. We don't know why they weren't there, but a lot of Timex Sinclair owners were awfully disap¬ pointed with Timex's ap¬ parent lack of interest and support.

On a brighter note, Jim Warren, known as the Faire Chair, was delighted with the great turnout. You would be too, I'm sure, with 50,000 in attendance at $15 a head, which, to be fair* did let you in for all three days.

For those looking to learn, there were seminars, lectures, workshops and in¬ terest groups. The business person could shell out an

extra $125 to hear Arnold Roberts talk for five hours on “How to Select a Business Computer.1' Others, for free, listened to, worked at, and struggled through such sessions as “Venture Financing for New High Tech Com¬ panies", “LOGO & Kids", “Word Processing", and “The Esoterics of Computer Games." For those yearning for fun, there were video games in abundance . . , and all free.

Next year they'll do it all over again. Same place, same time, but hopefully better weather. The 9th West Coast Computer Faire, which takes place March 23 to 25, 1984, is still looking for speakers. If you have a talk you know people are waiting to hear, call or write:

Computer Faire 345 Swett Road Woodside CA 94062 (415) 851-7077 The deadline is November 30th, 1983. We'll see you at the Faire!

— Joseph Gladstone

do not include the 600,000 T/SlOOOs sold since it was launched in July last year. The claim to be the first past the million mark is disputed by Commodore, which claimed it had reach¬ ed that point Last year.

Clive Sinclair, chief ex¬ ecutive and chairman, said he is very pleased with the figures. “They are a magnificent achievement for all concerned. With the 2X81 entering its third year of production the figures demonstrate beyond doubt the long-term viability of the computer as a long-term consumer product ”

More than 200,000 Sinclair or Sinclair-based computers are now sold every month throughout the world.

The British newspaper The Guardian has named Clive Sinclair as the Young Businessman of the Year. The award is made annual¬ ly to people in Britain who have shown particular abili¬ ty in business.

Past winners have in¬ cluded Sir Michael Ed¬ wards, the man responsible for improving the ailing for¬ tunes of Britain's state- owned carmaker BL,

The award has caused some amusement as Clive claims to be neither young nor a businessman. At 42, he is more than twice the age of many of the young entrepreneurs now reputed to be making vast sums from the rapid growth of the home computing market in Britain.

• See our pro/ile of Clive Sinclair beginning on page 62.

U.K. Hoax Exposed

Last April, the British counterpart to this magazine, Sinclair User, ran a program entitled “Machine Code Converter"

^4%

14

that was amazingly economical — only 27 lines long. “Now a brilliant piece of programming enables the Basic programmer to con¬ vert his listing automatical¬ ly into machine code by LOADing from a tape or by entering the program line by line from the keyboard,'1 claimed the instructions alongside the program. But readers discovered dif¬ ferently when they tried if and found an unexpected message printed on their screens: APRIL FOOLS!

“We got great feedback on this,’’ says Editor Nigel Clark. “Most of our readers just loved it. But one man was so disgusted he cancell¬ ed his subscription."

Oh well, seems some peo¬ ple can't take a joke, 0/S

TIMEX SINCLAIR USER

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Sinclair Programs and Sinclair Projects!

TIMEX SINCLAIR COMPUTERS — originated in the U.K. three years ago where there are now over one million users. Sinclair User Annual gives you the cream of their programs, projects and ideas!

T/S1000.ZX81 — get more fun, more knowledge, more programs, practical projects, hints and tips from other enthusiasts. Take advantage of their experience to get more from your computer.

YOU GET — 116 pages including exciting software and hardware reviews, graphics ideas, 19 pages of program printouts, a Spectrum (T/S2000) preview, technical information, programming help and much more! -

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The Great Connecticut Kit-Building Experiment

“The children worked with an intensity and excitement I have rarely seen in my years of teaching”

TIMEX SINCLAIR USER June 1983

For New Haven teacher Chris Baldwin and 28 kids who enrolled in his 10-week ZX81 workshop, it was a resounding success

IT USED TO BE THOUGHT, and still is in some school systems, that programming instruction and hands-on computer time belong in the high schools. It is now finding its way into the grade schools, more often as a result of student and parent pressures than of the vision of school boards. I’ve seen typical nine and ten-year-olds program in BASIC, and six and seven-year-olds in Logo. Kids with this learning opportunity have a tremendous, perhaps decisive, ad¬ vantage — but only a few have this opportunity! Until schools recognize their responsibility and

provide every child with daily ac¬ cess to a computer, this sad waste will continue.

That’s a strong statement, but the more I work with children and computers, the more I see what the experience can mean to a child’s self-image. I know a child has made an important breakthrough in how she sees herself and her world

“The more I work with children and computers, the more I see what the experience can mean to a child’s self-image”

when she stops asking 4How do I do X?’ and begins saying, ‘I wonder if this will do X?' She returns to a natural approach of playfulness and discovery about her world in a school setting in which many pressures work to dull that ap¬ proach.

One point I continue to make to policy-makers {with limited success to date) is to ask them to carefully consider which expenditure of $2,200 best serves a school's needs: one Apple II with a monitor, printer and disk drive, or eight T/SlOOOs, televisions, cassette recorders, printers and 16K memories? Through my work with kids and computers, I became con¬ vinced of the importance of giving all children free access to com¬ puters.

¥ N THE spring of 1982, I placed an A ad in the school newspaper of¬ fering to help kids build ZX81 kits. Parents were to pay $150 for a kit, all supplies, and my time: a reasonable charge as the complete ZX81 alone was then selling for that price. I expected half a dozen replies: within Four days I had 28, mostly from 10 and 11-year-old boys. In this age group it is hard to attract girls to what they already see as a male realm.

There was no screening of kids for this workshop. They

TIMEX SINCLAIR USER June 1983

Chris Ra/dmn (above) and kids; no problem was an solvable,

represented a valid cross-section of abilities and experience in kit- building and computers. The com¬ mon thread was excitement and in¬ terest about computers. Most did not know how to solder; most did not know what soldering was. Could youngsters master this delicate art?

As the starting date approached, my wife's worries that I had bitten

off more than I (or the kids) could chew raised doubts in my mind — doubts about working with so large a group on a project requiring pa¬ tience, certain fine motor skills, and care in following directions. When I saw a review in a popular computing magazine that asserted that building the 21X81 kit was a

More than half the computers worked when they were first plugged in

project to be undertaken only by adults, my concern grew.

By the third two-hour session, all our doubts had vanished. The children worked with an intensity and excitement I have rarely seen in my years of teaching. Sure they made mistakes along the way, but all were caught and corrected. No problem was unsolvable. An in¬ complete kit necessitated a letter to Sinclair; a few lost pieces necessitated several trips to Radio Shack; a few solder burns necessitated we keep first-aid sup¬ plies handy, I threw my back out and conducted several sessions flat atop a table.

I anticipated the children would finish in six or seven sessions and spend the rest of the time using their computers; week by week, an¬ ticipation and worry grew over whether the computers would work.

They were completed between the eighth and tenth sessions. When we plugged them in for the first time, more than half worked right away; after faults were discovered and repaired (the most common were shorts in the sockets and under the keyboard connec¬ tors) most of the others also became functional. Only one had multiple problems, including a cold solder, which took longer to track down. In the months since, there has been only one failure we have not been able to correct ourselves.

You see stories in the local press headed, “Whiz kid builds own com-

17

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puter,” but it somehow seems too frequent an occurrence to justify calling anyone a whiz. I believe that just about any 10-year-old could do it if given the opportunity and minimal guidance.

Last September, I started the New Haven Sinclair Study Group to provide continuing stimulation for kids using Sinclair computers. We meet on alternate Tuesday nights through the school year. Half

“Can 11-year-olds master the delicate art of soldering?”

of each meeting is given to a discus¬ sion demonstration or lesson, and the other half to sharing work, com¬ paring problems and exchanging ideas.

T LIKE TO TELL KIDS that the Sinclair case is black only to those who will not look at it; to anyone who uses the computer, the case is really transparent and Clive Sinclair meant for everyone to see inside it and understand it and put it to work in new and better ways* I hope the kits become available again and that the T/S2000 finds a place in our schools. That way; we can live up to Clive Sinclair's philosophy of bringing computer power to all the people. Computers are very powerful tools, and we need to see ourselves in a position of mastery, not intimidation.

— As told to Boss Williams

Comments from the Kids

TATE asked the members of the New Haven Sinclair Study Group to tell us * ■ about the ZX81 and their experiences building it, Some of their comments:

I can remember the first day of the computer club how scared I was. It seems silly to think of it now but I was really scared, I thought I would get burn¬ ed or something. It looked so confusing I mean when I opened the box the parts were kept in for the first time all I saw were tons of little odds and ends. These odds and ends are now my ZX81.” _ Avery Grauer oge j ,

I can barely remember trying my first solder. I was so nervous 1 could barely hold the soldering iron* After I had completed my first solder, I thought, well, I ve only got 299 solders to go! And believe me those 299 solders were not easy!"

— Kent Zimmer maun, age 2 1

“I kept messing up by filling holes with solder and putting diodes in the wrong holes. After I finished, it did not work, but with some adjusting it worked ^ine' — Jennifer House, age 1 1

"It was fun building it"

— Andy Cohen, age 9

"It is so small, light-weight and compact it’s hard to believe it is a computer."

— Wyeth Friday , age 1 1

The ZX81 is a very good first computer. There are a lot of things you can do with just IK that you wouldn't dream of doing when you first get it home."

Michael SJavinsky, age 1 1

TIMEX SINCLAIR USER June 1983

19

GlSDSTOftf- BlECTROfUCS GtSOSTOflE -ElBCTROfltCS GtaDSTOH^ BtECTROfltCS GiaifSTOHl BtECTROfHCS GlBOSTOflf EtECTROMCS GiaOSTOFtE BtBClROttlCS GlROSTOnB- BtECTROOtCS

The Complete ZX81 and TS1000 Library!

BOOKS

The Complete ZX81 Basic Course

Basic Course Cassettes (2) . . B7D $29,95

Getting Acquai nied with you r 2X8 1 C 70 $8 .95

ZX81 Pocket Book . .. . . . P70 $10,95

Making the Most Of Your ZXSi . . P71 $10.95

Computer for Kids, ZX81 Edison . . C71 $4.95

Explorers Guide to the ZX81 . . T7Q $1 2.95

ZX81 Companion . . . G72SB.95

49 Exploding Games for the ZX81 ........... P72 $10.95

Not Only 30 Programs for ZX81 IK . B72 $9.95

Machi ne Language Made S i mple . B73 $1 4,95

Mastering Machine Code on your ZX81 ... P73 $1 2,95 ZXB1 Rom Disassembly: Part A Both for

ZX01 Rom Disassembly: PartB . ..»»« — $19.95

Understanding your ZX81 ROM „„„„ . 076 $14,95

NEW RAM PACK STORES 16K EVEN WITH POWER SWITCHED OFF

CRAM 1C -61 is a 16K RAM pack using CMOS technology for per mane n l data retention. Data can be stored almost indefinitely and loaded almost instantly with virtually zero chance of erro.

CRAMIC-81 module uses chips made in a special CMOS technology which require only a tiny amount of power lo retain data when not actually in operation. A slat e-oMbe art, long life (10 years) lithium battery sup¬ plies this power in the standby mode. In the active mode, power is taken from the ZXSi. Used on its own it behaves like an ordinary Hampack EXCEPT that it can be powered down and removed Program and data lit It is permanently stored when this is done.

An ordinary Rampack can also be connected simultaneously. The two RAM units then occupy the same memory area but either can be selected Two separate programs can actoafy run alternately.

CRAMiC-Bi comes in an elegantly molded lie-fiat case with a cabled connector. ^ _ _ „

C12 $179.95

Cassette Software

ZX FORTH

A complete implementation of the FORTH language for the ZX81 and T STOOD computer

FORTH s most distinctive feature ■$ its flexibility The basic unit IS Ihe word — me programmer uses exist ing words to define his own which ear then be used in fur (her definitions FORTH i$ a complied language so pro¬ grams run very fast (typically five limes faster man BASIC!

ZX FORTH is supplied on cassette and is accompanied by extensive documentation 06 page Users Manual

8 pa ge E di I or M an ual ^43 *2® 95

ZX BUG

Machine Code Monitor and Disassembler

ZXBUG is a powerful tool ror machine language pro¬ gramming. It is 4K iong and uses memory from 71 EO to the top memory. ZX BUG works in hexadecimal (base 16), not decimal, so all addresses are a max¬ imum of 4 Hex bits long. Provides a total of 28 com-

mMdr Z41 $14.95

ZX ASSEMBLER

This Machine Code program occupies 7K of memory and locates it sell at the top of memory The program is a full Ed it ort Assembler and Monitor Labels may be used instead of any string. The features include Line Inser¬ tions Delete. Insert Characters, Auto Repeat on ail keys The monitor has facilities to inspect memory, registers and run machine code programs.

Z40 $1 4,95

TOOLKIT

9 Powerful New Functions!

RENUMBER This routine renumbers a program in any step and from any line up to 9999 DELETE This command deletes a group of lines in a pro¬ gram

MEMORY Prints how much spare memory is available DUMP Displays current values of string and numerical values except arrays

FilMD Will find any string ol up to 255 characters and list each line containing lhat string

REPLACE Replaces any string of up lo 255 characters by any other siring

SAVE Transfers program m computer to below RAM TOP

APPEND Allows two programs io be joined REMKILL Removes all REM statements from a program, otherwise leaving it unchanged, preserving memory

Z42 $14.95

Z- AID 1.0

Includes I he following routines

VERIFY confirms whether a program has been recorded properly on lape The program m memory is unallected. and a luriher ' save can t>e made if necessary Mioad/Msave enables a speed red block of memory to be Saved VPTR can be used within a BASIC program to eliminate many tedious POKES and PEEKS in hnding the addresses where variable values are slored CHAIN allows the second part of a BASIC program lobe loaded and lacked onto the end of the first part 2 AID 1 0 is convenient to use. being loaded from tape, and residing at the top Of 16K memory The user ac cesses Ihe various routines wilh USR calls while loading, running, editing and saving BASIC programs

wwmfiy Z98 $14.95

CRAMIC-81

16K

CMOS RAM

KEYBOARD

with metal case K71

A lull sized professional keyboard for the ZX81 Features 47 keys and a full-sized space bar Connects to the 2X8 1 with no soldering required, via ■ plug-in flexible connec¬ tor. You can purchase the keyboard only, or the optional metal case that holds both keyboard and ZXSi, Expan sion devices ji.e RAM packs, etc) connect to the ZX8t edge -conned or which extends from the rear of the cabinet.

■ American made * Keycap legends will NOT wear out • keys with life rated at 20 MILLION cycles

Keyboard K70 $79.95

Metal case tor keyboard

and ZXSI E70 $25.00

Giaosrons

64K RAM

Expands the capacity of the T/S 1 000 or ZX81 to its maximum User transparent. G64

Special $129.95

Z61 $19.95

♦ Allows you to LOAD and SAVE ZX81 programs up to 6 TIMES FASTER!

♦ Easy-to-use in your own programs

♦ User-transparent when incorporated into programs.

♦ Verifies proper loading.

♦ Catalogue feature lists program names and memory usage

♦ LOADER occupies less than 500 bytes (YzK) of RAM

♦ Consists of 2 separate programs — KEYBOARD MONITOR and FAST LOADER.

♦ Supplied on cassette with extensive documentation.

TINY LOGO *

Teach your children programming skills through a computer graphics language. It's easy and fun to use! Included with your program is a comprehen¬ sive guide. (Tiny Logo is a subset of the popular MIT Logo) $19.95

New! Write for your’s Today!

FREE

ZX81/TS1000 CATALOG

GLaDSTOnE-%€i

Mail order to 1585 Kenmore Ave. "

In N.Y. (716) 874-5510 Toll free (800) 833-8400

LECTROniOS

Buffalo N.Y. 14217 Checks or money orders. No CODs. Add shipping

TIMEX SINCLAIR USER

Have tun withZXBL AIS WOO Computing

TS1000-ZX81 OWNERS WIN $20,000

i fjTtn IVf HP4Wf ATMNkjR.

Z48 $19.95

KRAKIT™ consists of 1 2 clues on a ready- to-run ZX81 or TS 1000 cassette laps {16k RAM). The answer to each clue is the name at a country, a city or lown. and a number. If you are the first qualified entrant to solve alt 12 clues and declared the winner, you receive two tickets to the city of the secret KRAK1T™ vaUlt |Dca, tion When you arrive al that location, a cheque for a minimum amount of $20,000 00 (U S.) will be presented to you. The amount of the prize money is augmented weekly

Packl

Coniains 2 tapes with an instruction/applications manual with the following programs;

BREAK EVEN ANALYSIS; Enter expense items by name Enter revenue items by name. Enter fixed costs and variable costs Calculate break even point and plot expense and revenue curves. Backward calcula¬ tion by setting breakeven point quantity, expense or revenue.

CASH FLOW ANALYSIS; Enter income and expense Hems Caicuiate net income. Calculate discounted cash flow — PV and NPV Plot NPV for various in* terest rales

PAYBACK ANALYSIS: Enter expense and revenue items. Calculate years to payback.

tNTERNAL RATE OF RETURN; Enter expense and revenue Hems. Display net cash flow. Calculate IRR DEPRECIATION ANALYSIS: Enter depreciable amount. Select depreciation method and enter parameters. Calculate depreciation by any currently allowed method.

Z49 $29.95

Path U

PROJECT SCHEDULER: Record project est. hours, hours to date, remaining hours. Record billing rate, employees involved. Display amount billed, current billing, estimated billing remain¬ ing.

PROPOSAL SHEET: Record work items and hours. Record hourly billing rates. Display over¬ heads, material cost and labor totals.

250 S 14.95

CANADA: PRICES MAY VARY TIMEX SINCLAIR USER

DAMES

Pilot your space craft through a last moving, com¬ plex space maze Watch out tor miseries being fired from ail directions You can shoot back or evade them. Written in machine code for fast paced excitement.

Z90 $14,95

Blackjack al its best Black jack as it played in the casinos of Nevada. Up to five players can play against a dealer with a fifty- two card deck. Split pairs, double down, and even buy in¬ surance. The deck is reshuf¬ fled only when needed — allows for a continuous game Your winnings and losings are displayed after

“chh»na Z88 S9.95

Now choose from many great games!

ZX CHESS

Full graphic display of chess board. Six levels of play, two of which play within competitive time limits You choose black or white Plays all legal moves including castling and en passant You can save games in pro gress on cassette. Displays moves of game on screen, or output yo printer, for analysis Board can be set up in any position, you can even change sides mid-game. Clear entire board with one command; for end game analysis. Written totally in machine code. ZX CHESS (Enhanced) is a superb game tor the advanced chess

pla''*' Z85 $14.95

ZX CHESS

The strongest chess game available on ZX£i ZXCHES5 n has not ben beaten All the features ot ZX CHESS (Enhanced), plus much more Has a book of 32 opening moves Can play at ? leveis. four Of which play within competition time limits A move is suggested by the

Z86 $24.95

Here is your chance to beat the one-arm bandits . Slots lets you choose 5$. iQ$, 25$. 50$ and even $1.00 machine. Each machine has six sets of different graphics and pay according to the number ot coins you played Excellent, striking graphics, and lots of fun and excit-

™"' Z89S9.95

ZX Galax ia is an adaptation to the ZX8T of Ihe popular arcade game of the same name. You are being attacked by hostile Galaxians. and it s your mission to prevent them from attacking Earth

Z72S14.95

ZXB1 if requested

IK ZX CHESS

A good introduction to chess lor IK ZXfliH'StOOO owners Even within this limited memory space, a full graphic representation of the chess board is included Single level of play Does not accept castling or en- passant moves 2B7 $9,95

2K Chess H7S 1000)

(for unexpended T/S 1000) improved Chess game for an unexpanded TfS 1000 Setter graphics and a vastly superior range of moves ^55 $14 95

Your ZX&1 becomes the com¬ mand console as a diver descends Id the sunken sub¬ marine Nauiius to rescue as many of ihe stranded crew as possible Its a race against time as your oxygen supply must be replenished It s also a constant battle against marauding sharks which you can atlempt to blast with your laser ZBG $9.95

GALAXY INVAD

Z91 $14.95

An excellent version of the classic space game. Protect your seven lives against fleets of hostile invaders, who swoop down and aiiack quickly. T version is an ex¬ cellent demonstration of the capabilities of the ZX61 or TStOQG to entertain and ex¬ cite for hours.

I

S

ivr riuurs.

GLaOSTOnE-fELECTROniCS

In N.Y. Call (716) 874-5510 Toll Free (800) 833-8400

r — “ ~ — — —

CHARGE TO:

(□VISA □MASTERCARD

■ account number

I I I

| Datr?

I

Ejjhor gate.

Signature

riease rusn me	Quantity	Price	Tola)	1
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				"1
				1
				1

| NAMF _ _ _ _ _ _

| ADDRESS _ _ _ _

| CITY: _ _ STATE: , _ ZIP _

■ To: Gladstone Electronics, 1585 Kenmore Ave., Buffalo N.Y, 14217

New York Res add sales lax

C

SHIPPING

TOTAL'

Call or writs for free TS1000 $ ZX81 catalog

I

I

I

i

SY283

For wore information, circle 8 on Reader Service Card.

^^^^^^^—^^-G8^—Gt3DSTon£^£i*cTRomcs^—OiaD8Tonc- -c LfCTHontca GiaosTone- ^Lfcruomcs oiaosron^ tLECTRomcs at a os Ton e- ^tecTuomcs at a os to n ^iccmanics

Computers as teachers: do they work?

Computers are in our schools now, and students are using them every day. Are they dehumanizing? Do they teach anything? Will teachers reject them? Charles Durang, science and computer editor for Reston Publishing, explores some old computer myths

CAN you remember, not too long ago, when no one thought computers would get into the education business within our lifetimes? We heard most of the following:

“We won't use computers in our

schools because they are too expen¬ sive.”

“Computer-aided instruction is dehumanizing — it’s mass- production, lockstep, standardized education.”

“The computer can be a very

useful tool, but the teachers and ad¬ ministrators are too conservative. They may also be afraid of being replaced by the machines. It will be a long time before computers are accepted in the schools.”

“IPs another form of program¬ med instruction, and look what a bust that was,”

Well, it's time to take another look: each of those statements bears a little examination in the light of what's been going on during the last year or two.

Prices of all computers have been dropping rapidly, and with the ad¬ vent of the under-$100 Timex/Sinclair 1000 [nee Sinclair ZX81], there is no school district — and few families — too poor to jump on the computer bandwagon. One company is producing a

22

TIMEX SINCLAIR USER June 1983

BdteCcChotL*

L

package including computers, monitors, cassette storage units, software and perhaps printers — at

“Computers are too expensive”

a price for ten systems that com¬ pares to the price of one Apple- based system !

Today, the computer is proving, when employed for simple drill- and-practice exercises, to be more individualized, more self-paced, more forgiving and less judgmental than any teacher and classroom en¬ vironment can be. Computer-aided curricula are able to be more truly “competency-based” than anything that has gone before.

For inductive kinds of learning (although this kind of thing is clear¬ ly in its infancy as far as currently- available software goes), a com¬ puter program can support and manipulate a large data base for student exploration and discovery of facts and relationships — at the student’s pace, at the student’s direction, using the student’s

“Computer-aided instruction is lockstep education”

methods. We can learn how to learn even as we learn facts!

The misconception that lay beneath a lot of the anti-computer rhetoric was this: on the one hand you have a teacher, a living, feeling human being who will be sensitive to all the students in class and ad¬ just the environment to help them; on the other hand is the machine, inflexibly programmed to proceed at its own pace.

The reality is that the teacher cannot address every student’s needs simultaneously — in fact, the classroom environment mandates lockstep methods — while behind the computer is another thinking, feeling human being who wrote the program the student is using. The student is not learning from the computer, but from the program —

TIMEX SINCLAIR USER June 1 983

ultimately, from the teacher who created the program. By repeating tirelessly at the student’s option, moving ahead rapidly in response to student progress, and trying alternative approaches to the same concept when indicated, the com¬ puter provides the true self-paced and individualized environment. And the uncertain student will find his confidence growing in response to the program’s encouragement, rather than shrinking because of classmates’ derision or a teacher’s ill-concealed dismay.

Teachers are rapidly overcoming their legendary (and, it appears,

“The educators are too conservative”

largely fictitious) “computer anxie¬ ty” and recognizing the potential of this new medium. They are actively seeking to put the machines in the classroom; principals and superin tendants are putting them in the budget.

A recent survey by Market Data Retrieval shows that 24,642 school districts in the U,S, now use com¬ puters for instructional purposes, including 10,499 of the nation’s 52,000 elementary schools (an in¬ crease, at the elementary level, of 80 per cent over last year).

There is the recognition, on the part of parents as well as teachers, that today’s students will have to understand and be able to deal with computers to survive in tomorrow’s world.

There is also — though it is a secondary consideration — the fact that the computer’s basic data pro¬ cessing capability for record¬ keeping makes it easy to administer each student’s program in a way tailored to the individual.

Most important, of course, is the fact that educators realize the potential of all we said above, and that the microcomputer as “teacher’s aide” can provide both

“The computer is , . . more forgiving and less judgmental than any ■ teacher ...”

remedial and advanced self-study — at ever-declining cost — to sup¬ plement the teacher’s own efforts.

“Programmed instruction was a bust”

There is little doubt of the truth of that statement, and there certain¬ ly is a relationship between pro¬ grammed and computer- programmed instruction. There is even the chance that computer- aided learning will indeed suffer the fate of its predecessor. But the differences are encouraging:

1. The climate today is more receptive to a new approach.

2. The computer is innately more powerful, and more in¬ teresting to the students, as a tool.

3. The potential economic rewards are such as to attract the best people (educators as well as programmers) to the software ef¬ fort.

There is a lot of educational soft¬ ware out there already, but much more is needed. It is likely that, this time, the good will drive out the bad, rather than the other way around.

Perhaps the most exciting facet of the computer-assisted learning movement is the extent to which computers are being used at home for education of all sorts, and for every member of the family!

Parents are eagerly rushing to purchase personal computers to help their children learn at home —

Computer-aided learning at home

either because there are computers in the local schools, or because there are not! The resulting pressure from the home front is likely not only to speed the in¬ troduction of computers into schools, but also to improve the quality of education in general.

Such programs as Reston’s Self- Teaching Software for the ZX81- TS100Q: Mathematics I-VI are like¬ ly to be found much more exten¬ sively in homes initially, and find

23

TS1000-ZX81 OWNERS WIN $20,000

ENTER THE ULTIMATE ADVENTURE

SOLVE 12 CLUES LIKE THIS!

Where it ait began Where the torch was first fit Where muscfes and sinews strain, Where our heros win acclaim. Where the symbols hold the key.

KRAKIT ” consists ol 12 clues on a ready to-run ZXSi or TSiGOO cassette tape (t&k RAM) The answer to each clue is the name ot a country, a City Of town, and a number. If you are the first qualified entrant to solve aH 12 clues and declared the winner, you receive two tickets to the City Of the secret KRAKIT" vault location. When you arrive at that location, a check tor a minimum amount of $20,000.00 |U.S .) will be presented to you. The amount of the prize money is augmented weekly.

TS1000-ZX81

For more information, circle 17 on reader service card.

Mail to:

INTERNATIONAL PUBLISHING A SOFTWARE INC. P.O. BOX 1054, BUFFALO. N,Y, 14216

Please print:

Please send	_ copies of KRAKIT "
at $19.95 pkJS $1.50 shipping.
Total	enclosed is EH check EH money order	Name
Charge to	EH Visa EH Mastercard	Address
Number		City
Expiry _ _ _	Signature . ...	Zip

. State _

Allow 2 weeks for personal checks.

TIMEX^lN?LX!^Tj5yR june W

SdltCcrflOtL,

their way into the schools somewhat more gradually.

Also, because learning is not just for kids, many adults without children are buying home com¬ puters specifically to learn new skills or topics. People who cannot afford the time or money to take courses, or who are embarrassed for one reason or another about be¬ ing seen in a class, are embarking on their own programs of in¬ dividualized learning.

You can certainly anticipate the first suggestion from this corner: go get a computer if you don’t have -one! The Timex/Sinclair 1000 is a good starting place. While it is not a competitor to Atari for games, or to IBM for business applications, it is a superb learning tool — and a sophisticated machine that the pro¬ grammer will not outgrow as he progresses from novice to expert. Second, be conscious of the com¬ puter as an educational aid at home. Look for appropriate soft¬ ware for learning, not only for the children but also for the adults in the family. Remember this: your home computer is not only good for learning about various topics . , . and not only for learning about computers because they will be all around us for the foreseeable future . . - but also for learning about thinking and problem solving. Someone has said, and many have repeated it, that the computer will always do exactly what you tell it to do, which is not necessarily the

What can I do now?

same as what you want it to do. Learning to program a computer, even at a very rudimentary level, teaches clear thinking and problem-solving analysis in a way that the freshman Logic course always aspired to do.

Don't worry if, when you bring home your computer, your children only want to “play games/' First, they will learn from the games. Se¬ cond, they will next want to make up their own games — they will learn to program. And, perhaps

later rather than sooner, but almost inevitably, they will put that pro¬ gramming knowledge to work in other areas.

Educators, students, parents,

learners: you cannot go wrong by owning a computer today. You may not learn what you thought you were going to learn. But learn you will!

How educational are the ‘educational” programs?

we looked at five different educa¬ tional programs available for the T/S IOOO,ZX81.

MINDWARE'S Multiple Choice program begins with clear screen information and instructions, and guides the student very well through each stage. Basically, this program is a set of questions rang¬ ing from, "What is the capital of New York state?" to "What is the square root of 2?”

What the test does, it does okay. It does not meet our simple re¬ quirements, though, to really classify as an educational program. It does not hone in on specific lear¬ ning objectives. It does not teach anything. It does give a general in¬ formation test.

The more important part of this program is its ability to let you (stu¬ dent, parent, or teacher) create your own test. You put the pro¬ blems and answers into the pro¬ gram. Multiple Choice leads you clearly and easily through that pro¬ cess. In this mode, the program ac¬ cepts questions and answers of up to 32 characters each. After you have created your test, you can save it for later use. Thus you (teacher, student or parent) can create a file of tests on different subjects and of varying difficulty.

Another program that lets you create, save and re-use your own tests is called Flashcard. A flashcard is a device used in many classrooms. It has a problem or question on one side and a solution or answer on the other. On the T/S1000.ZX81 version, you put pro¬ blems on as many as 100 cards, and answers which are then mixed by

Joseph Gladstone Former educator evaluates some teaching software

KIDS DO LEARN from using computer games. This does not make those games educa¬ tional programs. To be educational, a program must teach something that somebody planned to teach. In the jargon of the schools, that is called a learning objective.

Further, to be educational, a pro¬ gram must show somehow that the kid has learned that objective. In a game, that's easy. You can see how well the player does . . . how many aliens were stopped or how many dots, dashes or stars eaten.

Games also have, built-in, the thing teachers call “motivation.” That is, kids want to do it.

Putting these elements together, we see that an educational program should have a specific goal, should motivate the child to do the work well, and have a testing system built into it. With all this in mind,

25

TIMEX 1000 COMPUTER * OWNERS *

IF YOU OWN A 16K RAM MODULE THEN YOU NEED A “CRASH GUARD” TO HELP SOLVE YOUR WOBBLE AND CRASH PROBLEMS

* NO DANGER BUMPING THE MODULE

* PROVIDES A SOLID WORK BASE

* MADE OF HEAVY GUAGE ACRYLIC

VISA OR MASTER CARD ACCEPTED

EXPENSE CUTTERS PRODUCTS, INC. P.O. BOX 9543 RAYTOWN, MO 64133 (816) 353-1690

10 DAY TRIAL PERIOD SATISFACTION GUARANTEED"

For more information, circle 10 on reader service card.

I . Peel of the touch sensitive key pad.

1 Plug in Klik* Keyboard {no soldering) and place in position.

3. Apply self adhesive two-colour legends to the keys.

This full 40 key keyboard has a positive dick feel as the keys are depressed but as it replaces the original touch pad it becomes a

1 80a Bedford Road, Kemptton, Bedford MK42 8BL ENGLAND

For more information, circle 1 1 on reader service card.

✓

SATISFACTION GUARANTEED OR YOUR MONEY BACK

TS-ART

TS ART helps you create graphics on the screen with a pencil, an eraser, about 120 brushes, a video inverser and a ‘flicker’ . You can easily move these tools in 6 directions or along lines or circles which are drawn, erased, painted with a brush, video inversed or "flickered'1. You can set a different background to any quarter of the screen. You can define new graphic commands — for example one that "does" a square. Then by pressing only one key you can make any of the tools do a square anywhere on the screen; so a square can be drawn, erased, painted, and so on. And the square can be rotated and it can be compressed or ex- panded to any size. And it can be used as a building block for other commands you define. And you can save or print the artwork. And , , .

TS-ART is very easy to learn and use, so 4 year old kids master its basic commands in minutes. Yet it is powerful and sophisticated to satisfy the most creative user.

TS-ART is fun; is a screen editor that can mix text with graphics; is a smart educational device (ages 4 to 99) that indirectly teaches {LOGO style) concepts in arith¬ metic, geometry and computer science by making ab¬ stract ideas visible and concrete

All this power (and more) for only $1 2.95 (add $1 .50 for s & h in U.S. or $2.50 outside U,S+). 16K RAM.

Win $50 if we use your artwork in our ads,

KSOFT, 845 Wellner Rd., Naperville, IL 60540.

Nam« - - - - - - - - - - - - - - - - - -

Address - - _ - - - - - - - - —

Qt y/St ate/Zip - - - - -

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Card Number _ _ _ _ _ _ _ _ _ — - Exp -

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Phone Orders (312) 96M250

For more information, circle 12 on reader service card.

TIMEX 1000. O-fll [80)

□ 8 Port 10

Interfaces up to eight one- byte ports Accepts 16K RAM

10 $89

□ JIDDA

2-channels A/D. 2-0 /A Computer sensing and control ot ( analog ) electrical devices (0-SV)

adda sea

□ Beeper [Clock Switch |

Programmable frequency tone generator, clock (milliseconds to years) . .

bcs m

Each board comes with educational docu¬ mentation, applications.

and applications programs _ - - — — .

(IK RAM). $5 handling VTIflCf Q

charge on all orders.

ORDER TOLL FREE:

BOO- 227 1617

operator 641 (CA, 800-772-3545 operator 641)

Box 1140

2000 Center Street Berkeley. CA 94704

developments

For more information, circle 13 on reader service card.

TIMEX SINCLAIR USER June 1983

26

fJRattn<j tAe frfuca/icno/ f/bfAmtie

	Graphic!	Ed. Value	Fun to Im	Work Book	Help tn School W'ork	Program	Mo nay Value	In«t ruc¬ tion!	Clrcla Reader Sarvlca Card No.
ATOR, THE
ABC GATOR (Timex)	S	9	8	No	9	9	Excellent	Good	52
COMPUTER TUTOR (Softsync)	8	6	8	No	6	7	Fair	Good	53
FLASHCARD (International Publishing)	7	7	6	No	7	7	Good	Good	54
MATH SERIES (Reston )	8	9	a	Yes	9	9	Excellent	Good	55
MULTIPLE CHOICE (Mindware)	7	7	8	No	7	7	Good	Good	56

the computer and presented to the learner in one of two ways: ran¬ domly with repeats for a set number of cards; or randomly with no repeats, but using all the cards. At the end of either test, your score is presented.

Both Flashcard and Multiple Choice let you put what you want into a good drill, review or test of that information. Neither one teaches, but either could form the basis of good trivia games.

Softsync has a series called Com¬ puter Tutor, We looked at two in the series, Math Raiders and Alpha/Vowel Tutor. I would have felt better if the word “tutor" had not been used; it is defined in the dictionary as “teacher,” but these programs do not teach. They do tell you if you are right or wrong and they do give you the right answers, but is that really teaching? We don’t think so!

In Math Raiders, the game con¬ cept has been well used to motivate the child. The student uses his math skills to ward off the landing of an alien form. Each weapon (addition,

subtraction, multiplication, and division) has two levels of difficul¬ ty. For fun, these programs rate high. For educational content, they rate low. They include too many different types of problems with too wide a skill range. They lack a logical progression in problem presentation.

Timex’s education program A tor, the ABC Gator, is extremely well done. It has eye-catching, high- interest graphics, great pacing and sound . , » that’s right, sound in a T/S100Q,ZX81 program. You or the child synchronize the tape through a simple but very effective count¬ down. The child hears original music and great instructions while working the computer. This com¬ bination of computer and tape recorder produces a fine educa¬ tional package.

The one fly-in-the-ointment in this package is the language used on the screen. A child learning the ABC s certainly cannot read the in¬ structions, A notice should be printed on the instruction sheet that an adult or a reader will be

needed to help the child use this program effectively,

Reston Publishing is the first to launch a full-fledged educational math program for the T/SlQ0G,ZX81, It breaks the math lessons into six sets, one for each grade from one to six. In each set there are 32 separate lessons; each introduces a problem, shows how to solve it, then drills and tests the student. They are total lessons bas¬ ed on sound classroom techniques. More important, there is a workbook for each set. After the student does a computer lesson, he or she completes a pencil and paper test of the skill in the workbook. The main drawback to the Reston program is the price. Each set (two cassette tapes, 32 lessons, a 64-page workbook and a vinyl binder storage case) costs $29,95.

ALL IN ALL, we were really disap¬ pointed with the programs that pur¬ port to be educational. For the T/SlOQG,ZX81 we recommend only the Timex and Reston materials.

TIMEX SINCLAIR USER June 1983

27

Check our handy chess guide

VWVW/WWWWWWWWWWWWVWWWWWWVWVWWWWWVWWWWWWWWWWWWVWWl

In a stalemate over which chess program to buy? Check here before you make your move and you won’t get rooked!

: You H notice 4^hcmA that Timefiare alone of lie j£Kgames forbids you to resign and that Super- ■ chess alone plays against itself drcouyh£\ ‘(bame Analysis * by the wayy allows you * to set up the board for specific prob - ' lens icahemdc Excuse me, m a little hoarse Achofeik It's all these cold knights.,. ^

PLAYING FEATURES

TO HELP you bring order to the wide array of software available For the T/SlOOQ.ZXai, our writers will look at specific types of programs in each issue. This month we look at six different chess games.

We set up an office tournament which pitted machine against machine, software program against software program, and people against them all. We found that each of these games is a worthwhile purchase; and that, frankly, our game has to improve a bit before we dare rechallenge any of the 16K games. All six use standard algebraic chess notation, but it doesn’t matter if you are unfamiliar with this system: only the Timex Sinclair program does not display the notation. 0^0

	recommends allows you moves to resign	levels of play	game analysis	plays itself	Castles	En passant
Time ware Chess	on levels 2 to 6	NO	6	YES	NO	YES	YES
Chessmaster	on levels 2 to 7	YES	7	YES	NO	YES	YES
Superchess	YES	YES	10	YES	YES	YES	YES
IK Chess	NO	NO	1	NO	NO	NO	NO
2K Chess	NO	NO	1	NO	YES	YES	YES
Timex Sinclair Chess	NO	YES	6	YES	NO	YES	YES

28

TIMEX SINCLAIR USER June 1983

GAME FEATURES

	saves a game	can change sides	can change levels	prints game	screen display rating	memory needed
Timeware Chess	YES	YES	YES	YES	7	16 K
Chessmaster	YES	YES	YES	YES	8	16 K
Superchess	NO	YES	YES	YES	9	16 K
IK Chess	NO	NO	NO	NO	7	1 K
2K Chess	NO	NO	NO	NO	7	2 K
Timex Sinclair Chess	NO	NO	NO	NO	6	16 K

you know that TimeWare and Chess r Master a How you to save un-\ finished games for later Jjhst $uperthess always shows past, mores, the others only upon t Mrnt?m ‘Screen display' t measures the clarity ana '.usefulness of the displays. ' . , .^,}&ax*leofitoio?,

' How shout that f ‘Packaging** measure the *u$tr~ friendlihMo « each package on a scale ofltolO too! Care to . join me in a coup againstj ' theKing? >

OVERALL FEATURES

clarity enjoyability

play

speed of response

i	instructions	of game	packaging	(average)
Timeware Chess	7	9	9	8
Chessmaster	7	9	9	9
Superchess	9	9	7	8
IK Chess	7	6	9	8
2K Chess	7	8	9	8
Timex Sinclair Chess	8	7	9	8

game

skill

W^WWWWMWMWW^^^VWVVVVVVWWVft

r TIMEX SINCLAIR USER RATING (1-10) editor's circle reader

Timeware Chess	7	8	8	57
Chessmaster	9	9	9	58
Superchess	8	9	9	59
IK Chess	5	5	7	60
2K Chess	6	6	7	61
Timex Sinclair Chess	8	8	7	62

’< You'll notice that' Che$sJfa$ter\ ' gets the best \ rating and — If hat are \tho$e two up [ there plotting, against Jme *

.now l,

TIMEX SINCLAIR USER June 1983

-ttvu k proffr&w

r

m

£

Go with the flow and no illogical jumps

IPO	DIM	EH	<10 0, 3 <1 )
300	IF	A*-	"1“ THEN	GOSUB	2 0 0	0
10 0	IF	At*	"2" THEN	GO SUB	300	c
500	IF	At*	" 3 " THEN	COSUB	ICO	0
60 0	IF	At-	"1" THEN	GOSUB	50 0	c
7C0	IF	At"	"5" JHLn	GOSUB	60 0	0
800	CLC
900	GOTO 2	00
100 0	CLS
10 20	PRINT	TAB 12, '	MENU	1 1
1030	PRINT	AT 5,7;" 1	SEARCH	I'
	"2	DJ	SPLAY FILE " t	AT 9	y
	AT	11,	7 * "1 SAV	E FIL	E-
	II ir	CR	EAT E FILE
1035	PRI	NT	AT 18,5;"	ERIE	OP	-r l
1 0 1 0	IMP	UT	A t
1 05 C	IF	At*	11 " THEN G	□TO 1	(J 1 0
106 0	RETURN

LE ;"3 " | AT

’■;ai 7,7;

LOAD I'lLE 13,7

“Jf *

t

I UN <1"5>

Listing 1

John Gilbert continues his course

Last month i explained how to draw a flowchart of a pro¬ gram by splitting it into parts. Each part corresponds to an operation performed either by the user or the computer program. This month we take that a step further and examine a way of breaking a program code into easily- understood areas.

There are three main operations performed in a program — input, processing by the computer, and output. Each of those operations has a distinct box in a flowchart and each has a distinct part in a program. If a beginner is to use the program the input section will be the longest, because of error- trapping techniques and instruc¬ tions. The processing part of the program will be the longest if a technical person, such as a scientist who knows about computers, uses it.

Now to deal with methods of prompting a user to enter informa¬ tion into the computer and the best ways in which the computer can handle that information. With pro¬ grams such as the database, which is to be constructed in this series, the screen display is very impor¬ tant. The computer uses the screen to display information to a user.

Many people who use programs such as database or word pro¬ cessors will know nothing about how a computer works or what it expects as input. The more infor¬ mation given to the user by a pro¬ gram the better. That does not mean clogging the screen with vast quantities of text. Instructions on the screen should be easy to read and well-spaced. The clear screen command should be used as often

30

as possible to break-down informa¬ tion into easily-read pieces but at the same time the jump between one screen of instructions and another should be almost transparent to the user.

The text must flow naturally and there should be no illogical jumps in the instructions. That is a matter of experience but the database has been designed with clarity of in¬ structions and prompts for inputs in mind.

The most important instructions should stand out from the rest. That can be done by liberal use of the GRAPHICS mode.

Listing one is the menu subroutine for the database. One thing people tend to forget is that they have the use of all the screen. Do not cram things into the corners or sides of a screen. Titles should be central and if there is only an IN¬ PUT prompt on the screen, a good place to put it is the top left-hand corner.

Listing one is the first module of the program. If there is a menu in a program it should be situated at the top of the code after any single or array variables have been declared, as in line 100 of listing one.

The menu module will display

Listing 2

10 0 0 REM LOnlJ ROUTINE 1C 10 CL3

1015 PRINT AT 0 , 0 J "NAME FILE TO BE ENTERED " inio INPUT Ct

1030 IF Ct = " " THEN GOTO 'Hi 10 1010 PAUSE 10 1012 CLS

1015 PRINT AT 0, 0*" SET UP TAPE AND PRESS ENTER" 1050 PAUSE 10000 10 AC LOAD Ct

1070 PRINT AT 0,0* ‘'FILE LOADED 10SC PAUSE 100 1090 RETURN

the options available from the pro¬ gram; ask which you require, put the number of the option selected in a string variable A$, and transfer to the control program, also in listing one, at the top of the code. The control program, consisting of a series of IF . . . THEN instruc¬

.Isting 3
soon	REM S	AVE	RCU
sort	CLS
5010	PRINT	AT	0,0
5(512	INPUT
5 CIS	IF C*	if it	THE'i
5030	PAUSE	10
SO 22	CLS
5035	PRINT	AT	0,0
5 03?	PAUSE	TOO	00
50-90	PRINT	.. f	ILE
5050	SAUE	Cl
50,5(5	PRINT	.. F	ILL
5(570	PAUSE	100
5080	CLS
5090	RETURi	N

tions, will then transfer to the subroutine selected from the menu.

The two other modules which are listed in this article are for LOADing data files — listing two — and SAVEing files — listing three.

The displays in both the SAVE and LOAD routines are important. Error messages should be displayed

in the same position on the screen every time they appear. Every pro¬ gram should have a standard error message area to which the user will become accustomed. In the case of the database, that is in the middle of the screen.

The prompts and information in the SAVE and LOAD routines may seem simple and not worthwhile but the writer knows about the in¬ ternal workings of the program and what to enter. A newcomer to a program, on the other hand, needs to be taken through it step by step.

When a module of a program has been written it is a good idea to test it on a friend or relative who knows nothing about computers. If they can follow the prompts, leave the display as it is; if they are confused, you know you have more writing.

I have now shown how the database is controlled using the menu and how to ease a user’s task in getting through the program.

e/'e

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TIMEX/SINCLAIR

INTO A REAL COMPUTER?

Try our plug-together systems.

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THE TOMB OF

DRACULA!

HORROR ADVENTURE GAME!

forthe16K TS1000/ZX81 OR 48K TS2000/SPECTRUM

A superb 3D graphics adventure game! Enter Dracula'stomb at 30 minutes to sunset . wander through the tomb's pre- mapped 300 vaults in search of the fabled Vampire' s Treasure P*4* yP valuable silver stakes and use them to defend yourself against the lurking horrors . . . ghouls, zombies, pits of primaeval slime , See them all on the computer's plan of the tomb , . + when it will let you! Take a chance on a Mystery Vault ... if you dare! And all the time the minutes are ticking by to

sur,set . wh*n Dracula rises from his coffin and comes after

you! Each of the infinite levels of the tomb has its own 300 vaults ... go as deep as you like, the Pnnce of Darkness will seek you out in his blood-lust! WARNING: people of an exceptionally nervous disposition should play this game only during the hours of daylight! Special facility lets you save a game in progress onto tape so you can continue it whenever you choose.

For TS1 000/2X81 with 16K RAM . $14.95

For TS2000/S PECTRUM with 48K RAM . $14.95

Price includes ready-to-load cassette with library case and inlay, full instructions. AIRMAIL postage and packing. Order today r Money refunded if not delighted!

Send cash or cheque to:

FELIX SOFTWARE (DEPT. SSU1)

19 Leighton Avenue, Pinner, HAS 3BW, England.

For more information, cireJe 14 on Reader Service Card.

For more information, cfrde IS on Reader Service Cord. 31

ZEBRA JOYSTICK ADAPTOR

Allows you to connect any Atari compatible joystick to your ZX81 or TS1 000.

6 DIRECTION + FIRE CONTROL

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6 JOYSTICK GAMES $9.95 ATARI JOYSTICK $6.50 ADAPTOR $19.95

The ZEBRA Joystick Adaptor comes assembled and tested with simple instructions to make joystick versions of most action games.

Use your own Atari compatible joystick or add $6.50 fora genuine Atari Joystick.

15 DAY MONEY BACK GUARANTEE

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C110 Keyed & Labeled ZX Connector $5.95 C111 Universal Prototyping Board $9,95 Cl 12 Expansion Connector . . $2,50

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32

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DBpt‘ A more in/ormalion, circle IB on reader service cord.

add si, M PER ORDER FOR SHIPPING

WE ACCEPT VISA. MASTERCARD CHECKS. MO COD ADD$3 0GEKTRa NY RESIDENTS ADD SALES TAX OVERSEAS FRO APO ADD 10*. DEALER DISCOUNTS available

TIMEX SINCLAIR USER June 1983

THERE is an over-abundance of Space Invaders games, but this one is worth a try because it fits into IK of memory, A fleet of 20 "X” ships is attack- ing you. You must destroy at least 15 of them or be destroyed.

The cursor arrows move you up and down (the shift 5 and shift 7 keys) and the 8 fires your laser can¬ non, You begin with 200 fuel units and use one every time you move or fire. If you manage to destroy all the “X” ships, the amount of fuel remaining is displayed.

10 let a- o rc let j^zgo 30 LET K-lfl TO LET G-0

50 LET X-IWF IftNUslO) * 2 60 LET A=A + l

70 If A~21 THEN CPTO 260 B0 LET Y^30

90 PRINT AT K,0;CHf<* 130JCHR* 12&JAT X,n'*X"

100 ir J < 0 THEN GOTO 150

110 IF- INKLVf^V" THEN LLT K-K-l

iza IF INKEY* THEN LEI K-K+ 1

130 IF INKEY THEN PRINT AT K# 2 J “** ^ tufim11

1^10 IF INKEY*>rtS" THEN LEI i

150 LET Y“Y- 1 ,5

160 IF Y "3 THEN LET G^G + 1

170 ir G^5 THEN GO W 2AQ

101) JE Y=3 THEN GOTO 5(1

1?H IF INKEY *=■ "8" AND K«X AND Y <2 1 THEN GOTO 220 200 CLS 210 GOTO 90

220 PRINT AT X, Y-n \ GHR* 1&9

230 GOTO 50

2A(J PRINT ** DESTROYED'*

250 STOP

260 PRINT '‘YOU WIN"

270 PRINT "FUEL LEm"fJ

TIMEX SINCLAIR USER June I9S3

33

Sixteen pins appear at the top of the screen for Bowling and the ball at the bottom. Use keys 5 and 8 to line up the two and press key 0 to bowl. The ball will be deflected by impact with the pins and thus make your task more difficult. For every pin hit you will add one to your score; the score is printed after eight balls and the game ends (IK )•

1	LET Q -CODE. 11 H				IF F > CGDL "(graphic EVl THEN GOTO CODE "(inverse )"
2	LET S*Q			45	IF INHFYV-"G” THEN G0SU6 CODE ’*W"
3	LET			5(1	GOTO CODE ,iJ'*
4	LEI M=CGDE "{urapitic	1 )"		611	PRINT AT YfrX+H}
5	FOR TO CODE, “(griping 4>M		65	IF PECK ( PEEK 16390 + VAL "256" * PEEK 16399) * CODE
6	FOR A^H+C TO CODE M (graphic E	)"-L		"T** THEN LET G*Ci+h
7	PRINT AT B* A ' "T"			711	PRINT AT Y,X+NJ *'0**JAT YfX-Mli "(inverse Oj,,#AJ Y*X+rtJ
13	NEXT A				11 ”
9	LET c-c m			75	LET Y-Y-N
in	NEXT B			GO	IF Y-h ti THEM LEI 1 -1 + H
u	LET X-CQDL “Cftraphit;	7 > "		90	IF O : G AND RND DAL "*5" THEN LLI X-X-fl
20	LET r=M			<?5	IF O > S AND RND VAL ",i" THEN LET X*X+h
25	LET Y-CODE ,4?"			100	LET S O
30	LET X=X + lIMKEY*^rtaM	AND X	LUDt " (graphic 1	l",! 110	IF Y=N-rt THEN RET OPM
	- i INKEY4 ”"5" AND X	CODE ‘,H<	}	120	GOTO CODE "W"
35	PRINT AT Y,XJ “ 0 *'			150	PRINT O

34

TIMEX SINCLAIR USER June 1983

Eleven-yeah-old Keith

Goode of Arlington, Texas, cer¬ tainly gives you your money's worth with this program. In the menu, Use It presents you with, you can choose one of seven op¬

tions. The first turns your computer into a drawing board. Option two draws sine wave curves. Three, four, five and six convert your keyboard into a mini-calculator* And finally, just for fun, if you

choose option 7, Keith has your computer show you its entire character set* Thanks, Keith * for showing us what you can make your machine do, (T/SlOOO,ZX81 16K)

io

20

30 40 50 6 0 70 SO 90 100 110 170 130 140 150 160 170 ItJtf 190 20 0 210 220 230 210 250

PRINT " USC IT"

PRINT "BY KEITH CODDC"

PAUSE 200

CLS

PRINT "MENU I "

PRINT

PRINT "1 > PLOTTER"

PRINT "2 SINE HAVE"

PRINT "3 AIJO"

PRINT "4 SUP T RAC J "

PRINT "5 MULTIPLY"

PRINT "6 > DIVIDE"

PRINT "7 CHARACTER LIST INC"

PRINT "a BULLETIN	guard
PRINT "9 NU1T"
I NT' LJ r A*
IF	A*: 'L" U1EN	Ml TQ	1000
IF	A*^"2" THEN	GOTO	200 0
IF	At" 3 11 THEN	UU 1 □	□ 000
IF	At- "4" THEN	GOTO	4 00 0
IF	At "5" THEN	GOTO	DO 0 0
IF	At-" 6“ THEN	GUI Q	6000
IF	At*"7" THEN	GOTO	/ 0 0 0
IE	At- "8" THEN	GOT U	B0 0 0
IP'	At "9" THEN	GOTO	900 0

605 CLS 1000 CLS 1010 INPUT A 1020 INPUT U 1030 PLOT A*L 10 40 GOTO UJUk 20 (JO CLE

2010 PUR Z=0 IQ *3

2020 PLOT 2,22 +20* SIN (I/32*PI)

7030 NEXT Z

2010 PAUSE 150

2050 CLS

ZIjoO GuTO DU

30 OC CLS

3010 iNf U f C

3020 INPU1 U

3030 PRINT C» fj

3040 PAUSE 200

□050 CLS

3060 dim DU

4 Ml 0 CLS

4010 INPUT L

4020 INPUT [

4030 PRINT t I 4040 PRINT L [

4L50	CLS
1060	GUT D DO
50 00	CLS
5010	INPUT G
5020	INPUT IL
5030	PRINT G*H
5040	PAUSE 200
DODO	CLS
DO 60	GOTO Do
6 LMT 0	CLS
6UUI	INPUT I
602 0	INF LIT J
60 30	PRINT l/J
6 (HU	PAUSE 200
60D0	CLS
6060	GOTO DU
7U0 0	CLS
70 10	FOR X-t* TO
70 20	PRINT CHRP
7030	NEXT X
7040	CLS
70DO	GOTO 50
B0 0 0	CLS
coin	INPUT Mt
UU20	PRINT ili
D030	GOTO SO Hi

TIMEX SINCLAIR USER /une 1983

35

KNIGHT’S MOVE uses the movement pattern of the knight in chess to try to cover every space in a square* The pro* gram asks where you wish to start on the board, giving the vertical co¬ ordinate first, and then marks the moves as you make your way round the board

There is a check routine to make sure you cannot cheat by making an incorrect move or land more than once on the same square. When no more squares can be visited, enter 0 as the number for the next square.

Press ENTER to replay the game or any other key and ENTER to end the game*

The graphics in line 20 are the capital I reversed with two revers¬ ed dashes (shifted) between each* In line 30 the dashes are replaced by reversed spaces. (T/S10QQ,ZX81 16K)

1 REM KNIGHT'S HQUE ID DIM 8(8,8)

2D tET I— I—I— I— I— I— -IM

3D LEI 8$*«I— J— I— I— I— I— I— I— 1“

-*10 CLS 30 EAST

60 PRINT TAR 61" X 2 3 * 3 6 7 8"

70 PRINT TAP 5; A*

SO FOR L=*l TO U

90 print tab 3;l;°‘ °;b*;tab 3;a* inn next l

110 TOR L-l TQ 8 120 FOR C = 1 TO 8

130 lit e<un-o

HO NEXT C 150 NEXT L 160 LET M30 170 SLOW

180 PRINT AT 20, QJ "WHERE DO YOU WISH TO BEGIN"

190 INPUT Ci

200 G05 UD 4 1U

210 IF L-9 THEN GOTO 18U

220 LET M-H+ 1

23 Cl PRINT AT L*2tC»3+3iH

2*0 IF M < ID THEN PRINT AT L*2 ,0*3+41*' 11 250 LET Ll = L 260 LET Cl-C

270 LET B<L,C>-=1

28 0 IF M < 6* THEN GOTO 310

290 PRINT AT 20 t 0 J "CONGRATULATIONS"

300 GOTO *90

310 PRINT AT 19, 1);" 10 SPACES "

320 PRINT AT 2U,0; "WHERE Dtl YOU WISH TO GO NEXT0 330 INPUT Ci

3*0 IF Ci^Q" THEN GOTO *90

350 GPSUB *1(1

360 IF L-9 THEN GOTO 32U

370 IF L-L1'2 OR L-Ll+2 AND C-CJ-1 OR C-Cl+1 THEN GOTO 220

380 IF L=L|~1 OR L-Ll+1 AND OC1-2 OR C-Cl+2 THEN GOTO 220

390 PRINT AT 19,0} "IMPOSSIBLE"

*00 GOTO 320

*10 PINT AT 2Q,0rf 2Q SPACES *20 IF LEIN Ci <> 2 THEN GOTO *70

*30 LET L-UAL CiM)

**0 LET C-UAL C$<2)

*50 IF L<l DR L>B OR C<1 OR 08 THEN GOTO *60 *52 IF 8 ( L f C ) = 1 THEN GOTO *60 *5* RETUF*N *60 LET L-9

*70 PRINT AT 19,0; “IMPOSSIBLE"

*80 RETURN

*90 PRINT AT 21,0; "NL TO REPLAY ■■

500 INPUT C*

510 IF Ci""" THEN GOTO *0

36

TIMEX SINCLAIR USER June 1983

—

YOU WILL probably recognize Surround as soon as you RUN it. It is a version of a fairly standard routine in which you are required to surround your adver¬ sary before he can surround you. Both players are in continuous mo¬ tion and are not allowed to cross their tracks or those of their oppo¬ nent, or to hit the boundary or the score display.

What will surprise you is the way in which the T/S1000,ZX81 can recognize two keys when pressed simultaneously. That is not possible using INKEY$ and is achieved by utilizing address 16421. This con¬ tains a number which changes as groups of keys are pressed. Lines 185 to 260 translate the number in¬ to a series of possible moves.

Black uses keys 1-5 to move up, Z-V to move down, Q-T for right and A-G for left. Grey uses the keys 6-0 for up, Y-P for right, B-M for down, and H-ENTER for left. After a crash the other player scores one; the winner is the first to reach 15, The routine enabling two players to participate can obviously be used in many graphics games. (T/S1000.ZX81 16K)

1 REtt SURKbUNE) BY J.MINCHI.STEB

5 LET SX=0

6 LET SB*C

7 LET 0-PECK 163?6+256*PEEK 16397 10 POKE IM 13 1 0

20 PRINT AT Ct0f"+ + tt (+++ + >+♦* h+K + + ++ +++ + +

30 TOR P=1 TO 22

10 PRINT "+ +m

sn NEXT p

^ I, PRINT I 11 + 4 + +4 + + t + +4 + + -t + 4* 4- + + -r 4- fr * + + + f + + + + '■

7t) PRINT AT 2 1 2 tCTPi SXJ AT 2 ,23; SIR# 5P RH LET X^12 *0 LET Y"3

100 LET B^t2 110 LET 020 120 LET XI 0 130 LEI Yl = 1 1T0 LET 01*0 115 LET Cl— 1

lj0 If PEEK <0+14 Y + 33 * X) <> 0 THEN GOTO TOO 160 IF PEEP tO+l+C+33*B) O 0 THEN GOTO 30 0 170 PRINT AT X,Y;CHRf U30J JAT BfC;CHRiU34>

3RE> LET A-PEEE 16121

LET^Xl^j £*-222 DR A-1?0 OR A==251 OR A-1 126 THt 1<?(1 0R OR A-103 Oh A=U9 THt

2 00 IF XI O C TFfEN LET rl =0 210 IF A*235 OF< A=25l PR A^219 OR A= 1 £7 LET Y 1 m 1

715 IF A=237 OR A - 221 OR A -253 OR A- 109

LET Yl~-1

720 IT Y 1 0 THEN LEI Xl-0

730 IF A-231 Oh; A-239 OR A“23S UR A-237 LET Bl— 1

735 IF A-119 UR A-123 OR A-125 OP A-126 LET P4*l

700 IF' PI O THEN LET Cl'-tt 315 IF Oh: A-219 OR A* 2 23 OR A=22l

LET Ci*l

250 IF A - 103 OF* A L07 Ok A=1B9 OR A-191

i F T PI = 1

76P tr ci :: o them let bi o

770 LET X-X4X1 200 LET Y-r+f]

29 € IET £aE:+E 1

292 GOTO 150

300 LET I5X-GX4 1

3UI If SX < 15 THEN GOTO 7

320 STOP

100 LEI SB^lie+1

T10 IF SB 15 THEN GOTO 7

OR A-125 THIN OR A"- 125 THEN

□R A-230 THEN OR A=127 THEN

OR A-222 THEN m A~19B THEN

TIMEX SINCLAIR USER June 3983

37

A GAME which links the bug- baiting type of program with a battle against alien in¬ vaders has been produced by Sanath Yogasundrum*

When the game begins, the player is asked for a skill level, A or P, which stand for amateur or pro- fessional. It is advisable to start on the amateur level while the player begins to understand this complex game.

A small grid is shown in the bot¬ tom left-hand corner of the screen in which there are four aliens,

shown as X and $, with a soldier (*). The soldier has to dig a hole (O) and then lure the aliens into it, scoring 100 points for every X and 200 for every $.

The hole is dug by going into dig mode, pressing 2, and pressing the cursor key for which side of the soldier you wish to place the hole. The soldier can then be moved by pressing 01 to return to movement mode, and using the cursors in their normal directions.

A soldier can be killed either by falling into his own hole or being

eaten by an alien. The game lasts for the lives of three soldiers, although an extra soldier can be gained by scoring more than 3,000*

Two other limitations are that only one hole can be dug at a time and a hole cannot be dug beneath an alien. Once an alien has fallen into a hole it is filled immediately and the game continues.

Even after playing for more than an hour at the amateur level, no-one at Timex Sinclair User managed to score more than 1,300* (T/S1000.ZX81 16K)

38

TIMEX SINCLAIR USER June 2983

1 LET BEST = 0

2 PRINT "SKILL LEVEL? <A/P>"

3 INPUT At 5 CLS

10	LET SG=2
15	LET S=0
20	PRINT . HOLED UP" 11	>i
21	PRINT AT 14,15| "LEVEL * " J A*
22	PRINT AT 16, 10! "HIGH SCORE! " f BEST
23	PRINT AT 18,0!"	YOUR SCORE # " ! S
30	PRINT AT 20,0!"	SPARE MEN!"! SO
40	LET X-17
50	LET Y=Q
60	LET A=17
70	LET B=B
80	LET U=2l
90	LET V"=4
100	LET G“ 1
110	LET HX-15
120	LET HY=0
130	LET C*17
140	LET D"=4
150	LET E=I9
160	LET F=2
165	LET GG= 1 9
170	LET HM=6
195	PRINT AT U ,V;"*"
200	PRINT AT X, Y , " t"
210	PRINT AT A , B ! " * "
220	PRINT AT C,D;"X"
230	PRINT AT E , F i " X"
240	PRINT AT GG,HH!"X"
300	LET 0=141
305	LET M=X
310	LET N“Y
320	GOSUB 2000
322	LET FN345
325	GOTO 6000
335	LET X-M
340	LET Y^N
345	PRINT AT X* Y }
347	CDSUEi 24 3 0
350	LET ii^A
360	LET N=B
370	GOSUB 2000
375	LET W=4 1 0
380	GOTO 6000
400	LET B=N
405	LET A“H
410	PRINT AT A , B i " *"
415	GOSUB 2430
417	LET Q= 189
42 0	LET H“C
440	LET N=D
460	GOSUB 2000
47 0	LET H = 5 1 0
475	GOTO 6000
500	LET D’=N
505	LET C=H
510	PRINT AT C ,D , "X "
515	GOSUB 2430
520	LET H=E
54 0	LET N^F
560	GOSUB 2000
570	LET H=6 1 0
580	GOTO 6000
600	LET F=N
605	LET E=n
610	PRINT AT E,F!MX‘*
615	GOSUB 2430
620	LET H“GG
640	LET N=HH
660	GOSUB 2000
670	LET H-7 1 0
680	GOTO 6000
700	LET HH=N
705	LET GG=h
710	PRINT AT GG,HH!"X"
720	GOSUB 2430
770	GOTO 300
2B03	IF INKEYS*” 1 11 THEN	LET G=i
20 0 4	IF IN KEY *=="2" THEN	LET G=2
2005	LET ft=RND
2010	LET Z=RNC)

2020 PRINT AT rt,N!" 11

2090 IF H=18 OR M=2Q OR N^V AND A*^"P" AND

( N=0 OR N“2 OR N=4 OR N=6 OR N^8) THEN GOTO 212C 2100 IF R <= *5 OR M=U OR N=l OR N*3 OR N=5 OR N=7 THEN GOTO 2300

2120 IF M™2 1 OR U<H AND A*="P" THEN LET Z=.7

2122 IF M = 17 OR U>M AND A*=HPM THEN LET Z = *5

2125 IF Z <= ,5 THEN LET M=*H+l 2140 IF Z>,5 THEN LET h-M-1 2160 GOTO 2340

2300 IF N^0 OR N<V THEN LET Z^.5

2305 IF N=*B OR N>V THEN LET Z=,7

2310 IF I <* ,5 THEN LET N=N+i 2320 IF 2>*5 AND N>0 THEN LET N -N 1 234 0 IF M=U AND N=V THEN GOTO 7000 2400 IF INKEY$="2" THEN LET G=2 241(1 IF INKEY* 1" THEN LET G = 1 2420 RETURN

2430 IF INKEY * <> "5" AND INKEY $ <> "6" AND INKEY* <> "7" AND INKEY $ <> "El" THEN RETURN 244 0 IF G“2 THEN GOTO 2590 2450 PRINT AT U,V;" "

2520 IF INKEY $-"5" AND V>0 AND (U^17 OR U=19 OR U=21)

THEN LET V=V“1

254 0 IF INKEYf z?i,8" AND V<8 AND (U = 17 OR U=19 OR U = 21) THEN LET V=V+1

2560 IF INKEY**"6" AND U<21 AND (V=0 PR V=2 OR V-4 UR V=6 OR V=8> THEN LET U=U+1

2500 IF INKEY* ="7" AND IJ: 17 AND <V = Q UR V=*2 OR V = 4 PR U=6 OR V“8 ) THEN LET U=U- 1 25B5 GOTO 3005 2590 PRINT AT HX# MY J 11 11

2597 IF INKEY* = ,f5" AND V>0 AND (U»21 OR U=19 OR U-17J THEN GOTO 2700

2600 IF INKEY* -"8 " AND V<8 AND (U=2L OR U-U9 OR U^17) THEN GOTO 2750

262 0 IF INKEY* ="6" AND U<21 AND (V-0 OR V=2 OR V=4 OR V=6 OR V”B ) THEN GOTO 2800

2640 IF INKE Y*-"7" AND U>17 AND CV=Q OR V=2 UR V = 4 OR V=6 OR V“=0) THEN GOTO 2850 2660 GOTO 3005 2700 LET HX“U 2710 LET HY-V-1 2720 GOTO 3000 2750 LET HX”U 276!) LET HY-V+1 2770 GOTO 3000 280 0 LET HX-UU 2310 LET HY=V 2820 GOTO 3000 285 0 LET HX“:U 1 2860 LET HY“V

30 0 0 IF HX-X AND M Y - Y OR HX=A AND HY=B OR HX=C AND IIY = D OR HX-=E AND HY=F OR HX“GG AND HY=HH THEN LET HX=15 3003 IF HX <> 15 THEN PRINT AT HX*HY;M0M

3020 IF HX=U AND HY=V OR U=X AND V = Y OR U = A AND V=B OR U^=C AND V=D OR U*E AND V=l OR U=GG AND Vs Mil! THEN GOTO 70 0 0 3030 PRINT AT U,V!"*"

3040 RETURN

60 0 fl IF M=X AND N-Y OR M--A AND N-G UR M -G AND N=D OR H-E AND NSF OR M“GG AND N =HH THEN GOTO W 6005 IF H-HX AND N=HY THEN GOTO 6020 6010 GOTO W-10

6020 IF 0=141 THEN LET S*S+100

6035 LET S=S+100

6040 PRINT AT n,NfCHR* G

60 44 IF S/30 0 0 " INT (S/30 00) UR

(S-10 0)/30 00=INT< (S-100 )/:i(IOin THEN LET SO=SQ>l 6045 PRINT AT 1B,21?S 6047 PRINT AT 20,21!SO 6050 LET HX=1 5 6060 GOTO W-10 7000 PRINT AT U*V!"*"

7010 LET SQ=S01 7030 PAUSE 100

7032 IF SO—1 THEN GOTO 8000

7035 CLS

7040 GOTO 20

8000 FOR N-:0 TO 21

8010 SCROLL

8020 NEXT N

0030 IF S>BEST THEN LET BEST*S

8040 PRINT AT 0,0; "CAME OVER , ALL YOUR MEN ARE DEAD"

B(!50 GOTO 2

39

TIMEX SINCLAIR USER June 19B3

THE FIRST question often ask¬ ed about a new machine is "Does it play Space Invaders?" Though a IK machine has con¬ siderable difficulty getting anywhere Computer Combat using only IK, is a type of mini Space In¬ vaders but with only one invader and one base and a much slower rate of firing.

The object of the game is to hit the invader as many times as possi¬ ble before it lands or you run out of missiles. Twenty-five missiles nor¬ mally are given but that can be altered by changing the value of B in line 5,

You receive five points for hit¬ ting it but lose one if you miss. Use keys 5 and 8 to move left and right respectively and key 0 to fire. The invaders' missiles are shown as asterisks and yours as crosses. The program is good for beginners, as it is easy to understand the function of each line as there are none of the usual POKE and PEEK or other complicated functions.

If you want to get more memory, enter in direct mode the following be/ore entering the program: POKE 16389,68 followed by ENTER NEW followed by ENTER,

The program will run con¬ tinuously until the BREAK key is used.

Computer Combat was sent in by 15-year-old Anthony Wells, (T/S1000,ZX81 16KJ

5	LET B-UAL "25"
10	LET S*PI--PI
15	LET M»F‘I--PI
20	LET X-UAL "16"
25	LET Y^PX-PI
30	LEI i1=M-»2
35	If M>UALL "20" THEN GOTO UAL "	10 0"
40	CLS
45	LET R-INT <EN3*5>
50	IF R=-3 THEN GQSUB 155
55	PRINT AT M,YJ " VW1 "
60	LET Y-Y + UAL. "2"
65	IF Y-UAL "30" THEN GOTO 25
70	PRINT AT 21 ,X;" * "
-r tr /	LET X=X+( INKEY *="8" > *3 -(INKEY*	="5") *3
80	IF INKEYt=”0" THEN COSUB 115
	IF B <= UAL "0" THEN GOTO UAL	"10 0"
95	GOTO UAL "40"
100	PRINT AT 12,101 "SCORE”" 1 S
1 05	PAUSE UAL "300"
110	RUN
115	PRINT AT
120	IF X+l <> Y THEN LET S»S-1
125	IF X-H=Y THEN PRINT AT M,X~11"
130	IF X+1-:Y THEN LET E-S+5
135	LET B=B-UAL "1"
140	RETURN
145	PAUSE UAL "50"
150	GOTO UAL "40"
155	PRINT AT 21 , Y i CHR* 23
160	IF X--Y THEN GQSUB UAL "170"
165	RETURN
170	PRINT AT 2 1,Y ;"<*>"
175	PAUSE UAL "40"
180	LET S“S“UAL "5"
185	RETURN

40

TIMEX SINCLAIR USER June 1983

Join the CLICK !

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At last, a large 60 key "Tactile Feel” keyboard that plugs into the same connectors as the existing keyboard onyourZX81 oryourTimex-Sinclair 1000.

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- 60 Keys - Legends in 3 colors on the base ■ Molded legends on key tops

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- 2 Shift keys - Numeric key pad - 5" space bar. E-Z Key 60 requires no wiring (just plug it in) and can be adapted to fit the XZ80 or the MicroAce (8 KROM). The Mounting base measures 10"x4". Cables and instructions are included.

S8495

A custom made enclosure (shown above) is also available for your computer and E-Z Key 60 keyboard.

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SUITE 75 A, 711 SOUTHERN ARTERY QUINCY, MASSACHUSETTS 02169 (617) 773-1187

E-Z Key 60

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For more information, circle 9 on Reader Service Card.

41

F

-finis. £b'/>S \

Who says that graphics

All you need to start is a simple understanding of the PLOT command, says professor and author Michael K. Barnett in this exclusive interview

Can you tell us some of the com¬ puters that you use /or computer graphics?

These include some very large IBM machines like 370s, 3033s and 3081s, some personal computers like the Apple, and the Timex Sinclair 1000 home computer.

Does it make sense to use a TIS1000, ZX&l when you can use these larger machines?

Yes — a lot of sense. The T/S1000 and the large IBM machines are at opposite ends of what many people see as a unified scheme — for teaching and learning what com¬ puter graphics can be used to con¬ vey.

What are the limitations of TISlOOO graphics and how do they affect the fields where T/S graphics will be used?

The limitations are the resolution that it can provide on the television

screen, the amount of data that can be stored for reference, and the speed at which it calculates. However, I don’t see these locking the T/S 1000 out of particular fields where graphics are useful; within these fields, the Timex will be used where low resolution is adequate, perhaps as a preliminary to using higher quality equipment.

Where do you think Timex graphics will be used?

Education, business, research and engineering, and entertain¬ ment, for a start.

How will it be used in education?

Initially, to teach programming and computer literacy, to help teach math, to teach people how to use computer graphics in their work; as time goes on, in chemistry and other sciences, in social sciences and in educational ad¬ ministration.

How can it be used to teach pro¬ gramming?

Many people are afraid of com¬ puters because they are afraid of mathematics and formulas. And most people do not have ready ac¬ cess to a computer, or the money to spend on a terminal and phone bills. You can buy a T/S 1000 for the price of a couple of textbooks or a home appliance, and work with it in your own time and at your own pace in the comfort and privacy of your home. And the graphics let you start using commands based on the simple idea of using squared paper that people see around the house in patterns for knitting and laying tiles and so on.

You mean someone can get started just using the PLOT com¬ mand?

Sure. After PLOTting a few points in the immediate mode to get a feel for the numbering, you can write simple programs with FOR loops to draw straight lines and

42 TIMEX SINCLAIR USER June 1983

have to be complicated?

make them move. For example, just type

10 FOR X « 10 TO 50 20 PLOT X.20 30 NEXT X

and you get a horizontal line about halfway down the screen. Change the numbers in the FOR statement, keeping between 0 and 63, and this changes the length of the line. Change the Y value in the PLOT statement from 20 to any other value between 0 and 43 and you change the height of the line. And to get a vertical line, you put Y in the FOR statement instead of X, and you change the PLOT state¬ ment to PLOT 20, Y to draw the line roughly halfway across the screen. What about sloping lines?

Easy. Try

10 FOR N =0 TO 40 20 PLOT N,N 30 NEXT N

That slopes up from southwest to northeast.

And to get it to slope up from southeast to northwest?

Try

10 FOR N =0 TO 40 20 PLOT 63 - N,N 30 NEXT N

You can build lots of patterns using these tactics. Here is a simple ex¬ ample.

How many lines of code did this take?

This does it in 20 lines:

R /I «■ \ 1% I

i .• i jrm i % i L" L'UIIM M L k IX XI J J i% I'jin'i .*i

i % i -r-T i / i

I M k L* 1 I

I T" ’ " I f

I V d* I

T/S1000 graphics can be used anywhere low resolution is adequate

10 FOR K = 1 TO 4

20 FOR X = 32 - 2**K TO 32 + 2**K

30 PLOT X,21-2**K

40 PLOT X,21 + 2**K

50 NEXT K

60 FOR Y = 22-2**K TO 20 + 2**K 70 PLOT 32 - 2**K,Y 80 PLOT 32 + 2**K,Y 90 NEXT Y

100 FOR X = 33-2**K TO 31 110 PLOT X,X- 11 + 2**K 120 PLOT X,53-X-2**K 130 NEXT X

140 FOR X = 33 TO 32 + 2**K

150 PLOT X,53-X + 2**K

160 PLOT X.X- 11 - 2**K

170 NEXT X

180 NEXT K

190 POKE 16417,1

200 COPY

Perhaps your readers can shorten this or speed it up, for example by calculating 2**K just once in each cycle.

We’ll ask them. Timex graphics certainly let people learn about coor¬ dinates and FOR loops very quickly.

Yes. And about interactive design.

I thought that needed very expen¬ sive equipment. Isn’t it the sort of thing that car manufacturers do?

Try the following program. It won’t let you design a car, but it does illustrate the basic tactic of in¬ teractive design.

10 LET B$ = “

20 LET B$- B$ + B$ + B$ + B$

30 PRINT AT 0,0; “XLO.XHI.Y: “

40 INPUT XLO 50 INPUT XHI 60 INPUT Y

70 PRINT XLO; XHI; Y 80 FOR X = XLO TO XHI 90 PLOT X,Y 100 NEXT X

110 IF INKEY$ < > THEN GOTO 110

120 PRINT AT 1,0; “PRESS K TO KEEP, E TO ERASE;

130 IF INKEYS = THEN GOTO 130

140 LET R$ = INKEY$

150 PRINT R$

160 GOTO 300*[R$ = "K”) + 200* (R$ = “E”)

170 PRINT AT 1,0; B$

180 GOTO 110

200 FOR X = XLO TO XHI

210 UNPLOT X,Y

220 NEXT X

300 PRINT AT 0,0; B$; B$

310 GOTO 30

Statement 30 prompts for the values of X at the ends of the line you want the program to draw, and for the value of Y. Statements 80 to 100 draw the line. Statement 110

You can learn basic principles of animation on your T/S1000,ZX81

waits if you still are pressing any keys. Statement 120 prompts you to show whether you want to keep the line or to change your mind — this is what makes it interactive, Statements 200 to 220 erase the line if you request this. Then the cycle begins all over again.

% / W

* \j\aai woe tjic aujjit: JiiCrjp

to expand the program, to promj the user to type, say, D for a dot. j for a horizontal line and V for a ve

43

-ffitrfs. £fys \

tical line, followed by the coor¬ dinates . . .

Correct. The person learning can take off very quickly, varying and expanding the prototype programs for graphics.

Do these principles of graphics ap¬ ply to larger machines?

Yes. Using the T/S1000, students and architects and fashion designers and planners can get a handle on writing prompting se¬ quences at home. Then if they want larger or higher quality graphics, they can go to bigger machines and program these themselves or tell the programmers what to do.

Can you get animation effects on the T/S1000?

Yes. For example, patterns move

“We vastly under¬ utilize the resources at our disposal”

up the screen by SCRGLLing. To see this, just type:

10 FOR N * 0 TO 63 20 SCROLL

30 PRINT TAB N; 44 ”

40 NEXT N 50 GOTO 10

This seems to make lines of little darts shoot up.

I suppose if you turned the screen on its side you could get things to SCROLL sideways.

I would not recommend that with the family television set.

What i/ you want to draw a face with an eye that opens and shuts, or a caterpillar wriggling across the screen?

Easy. Many of the programs in my recent book Personal Graphics for Profit and Pleasure on the Apple

11 Plus Computer (with Graham K. Barnett; Little, Brown; $14.50) can be adapted to the T/S1000,ZXB1. “Winkface” draws a face and makes one eye wink. The outline of the eye is drawn first: on the Timex

you just use PLOT commands. Then if the center of the eye is at position XC,YC you make it blink by statements like

500 PLOT XC,YC 510 PAUSE 60 520 UNPLOT XC.YC 530 PAUSE 60 540 GOTO 500

This use of PLOT to draw and UNPLOT to erase, or its equivalent in other programming languages, is a basic tactic of animation. Try this ten-liner and meet Grenville the Graceful Grub:

10 FOR N = 0 TO 7 STEP 2 20 PLOT N,20 30 PLOT N + 1,21 40 NEXT N

50 FOR M-0 TO 54 STEP 2 60 UNPLOT M,20 70 PLOT M + 8,20 80 UNPLOT M + 1,21 90 PLOT M + 9,21 100 NEXT M

He wiggles across the screen from left to right. And you can vary the program easily to make grubs of dif¬ ferent lengths and shapes wiggle in different directions.

Here is a very different type of graphics demonstration — a very simple bar chart program:

10 LET B$ = "

H

20 PRINT AT 0,0;"MAXIMUM VALUE:

30 INPUT MAXIMUM VALUE 40 PRINT MAXIMUM VALUE 50 LET Y = 43 55 PAUSE 60

60 PRINT AT 0,0;B$;AT 0,0;‘‘CAP- TION, VALUE:

70 INPUT C$

80 INPUT VALUE 90 PRINT VALUE

100 LET Y = Y- 2

110 IF Y< = 0 OR VALUE>MAX- IMUM VALUE THEN GOTO 1000

120 LET R= INT (.5 + 50* VALUE /MAXIMUM VALUE)

130 FOR X = 1 TO R 140 PLOT X,Y 150 NEXT X

160 IF LEN C$>30-R/2 THEN LET C$ = C$( TO 30-R/2)

170 PRINT “ VALUE;”)”

180 GOTO 60 1000 POKE 16417,1 1010 PRINT AT 0,0; B$

1020 COPY

It prompts for the maximum value to be represented horizontally. Then it prompts for the captions of the bars and the values these repre¬ sent. It draws and labels the bars and, when you want to quit, you just press ENTER, type a number greater than the maximum value you typed originally, and press ENTER again. Here is an example of its output:

FI5H< 15) ■■■ MEftT(10>

" MILK<20)

. EGGS<£55

“ FRIJITC10) . 1111 OTHER <£0>

Most of the examples you have given are charts and geometrical shapes and patterns. Don’t you feel hampered by the lack of pictorial realism?

I look on it rather as a challenge to find what can be conveyed without so-called realism. I think that a very sad aspect of high technology in general is that we vastly under- utilize the hardware, software, mathematics and very sophisticated techniques at our disposal. Part of the problem is that we haven’t learned how to make the most of simple resources.

Do you think the smallness of machines like the T/SiOOO will stimulate new research?

Yes. 0/ 0

TIMEX SINCLAIR USER June 1903

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TIMEX SINCLAIR USER June 1963

45

Th

Build your own EPROM blower without blowing a

fortune

BECAUSE most users of the T/S100Q,ZX81 are software* orientated, the hardware has been made simple in this design. The software needed to run it con¬ sequently will be large and some of it is in machine code.

The heart of the design is the 8255 programmable peripheral in¬ terface device. This chip has 24 lines of input or output, which can be defined by software. There are only sufficient to handle the 2532 EPROM. Port A is used to output the eight least significant bits and port C for the remaining address bits and control bits. Table one shows which functions port C has for each of the two types of EPROM, The design caters for the 2516 and 2432 EPROMs from Texas Instruments. The 50ms pro¬ gramming pulse is timed by the hardware and PC4 output must return to 0 before 50ms has gone by.

A simple program is included to enable the programming of the EPROM. The machine code routine in the first REM statement will pro¬ gram one memory location and read that memory location. The Basic will call the routine as re¬ quired. The reason machine code is required is because the 8255 chip is placed in the I/O map of the Z-80 so that the memory map is left alone. In the T/S100Q,ZX81 the PEEK and POKE commands access only the memory map. As Sinclair has not fully decoded the I/O map it was difficult finding somewhere where the 8255 was not affected by the T/S100Q,ZX81,

Another reason for leaving the memory map alone is so that EPROMs can be placed above the 8K ROM. These could contain routines to improve the 8K Basic. Anyone building it is also advised to acquire a data sheet on the 8255, as the chip is very complex.

Stephen Churchman details how to expand the storage available for programs using inexpensive components

Referring to the circuit diagrams, two Nand gates have been used and three Or gates to drive the chip select pin. CS will go low only when AO, Al, A2, A3 are logic 1 and A7, IORQ are logic 0. That places the 8255 at 1FH, 3FH, 5FH, and 7FH. The other two Nand gates ensure that the 8255 and 50ms timer are re-set when power is ap¬ plied.

The only difference between the 2516 and 2532 EPROMs are two pins and that is why a switch has been included. When programming the 2532, the programming voltage must be switched from 5V to 26V and back to 5V either side of the programming pulse. With the 2516 it may be left at 26V to verify the

EPROM contents. The 26V regulator can be switched to 5V by the PG7 output going high, switching-on the BC108 and plac¬ ing a 5V zener across the 24V zener.

The power supply is standard, using a single transformer and half¬ wave rectification for the 5 V supply and voltage doubling for the 26V supply. It is best to make sure that the transformer you buy has two 9V windings in series aiding. The 50ms timer uses a 74123 TTL chip — only one half is being used. The diode And gate is needed as pin 20 of a 2532 needs to be low when reading (C5) and low for 50ms when programming.

The prototype is constructed on two pieces of Veroboardi the PSU on 0.1 5in, matrix and the main components on a piece of VQ board. It is wired with Verowire, which is ideal for a prototype, as modifications are easy to imple¬ ment. The final board is somewhat cluttered because an extra chip had to be added at a later stage to help with the decoding of the CS line. The transformer is bolted to the base of the case and a cassette-type mains plug and socket on the case.

The power transistor (BD235)

Figure 1: Driver circuit

BD235

26v

46

Figure 2; EPROM blower outside its case

Figure 3: P.S.U* diagram

Figure 4: Components

of small board

and voltage regulator do not need heat-sinks as they pass fairly small currents. The two boards are fixed on top of each other, with the EPROM socket emerging through a hole in the top cover of the box. The switch is mounted next to the EPROM socket.

With a REM statement on the first line of a program, the first character is at memory location 16514 decimal. The first four loca¬ tions are used to hold data for the machine code program, the machine code sub-routine starting at 16518,

16514 — BYTE FOR PORT B

16515 — BYTE FOR PORT C

16516 — BYTE FOR PORT A

16517 - READ FROM PORT A — used for verification.

Within the program, register F holds the byte for Port Ct anc

'omcs

ZX KEYBOARD FOR USE WITH 80/81 SPECTRUM

Our new cased keyboard has 5 2 keys, 12 of these are used for the numeric pad The numeric pad offers some useful features, you can cursor with one hand and it wifi be a boon for anyone who enters a lot of numeral data . The pad is a repeat of the I -9 keys plus it has a full stop and a shift key. The numeric pad keys are coloured in red. the normal keyboard keys are grey, with the case being black which makes the whole thing very attractive The case measures \S x 9 x 7Vi The computer (either 80/81 or spectrum) fits neatly inside. You will have to remove the computer from its original case, it is then screwed to the base of the case The case had all the bosses already fitted and the screw holes are marked Also fitted inside the case is a mother board (81 model only) which allows I6K. 32K and 64K to be fitted in the case All the connections are at the rear of the case i.e. Power, Mic, Ear, T V and the expansion port The case is large enough for other add ons also to be fined inside One of these could be the power supply, then you could very quickly fit a mams switch, or a switch on the 9V fine This means you have a very smart self-contained unit This case does not stop you from using any other add-ons that you may have e g Printer etc We are convinced that this is the best keyboard available at present It offers more keys and features than any other keyboard in its price range

SPECTR

16 K Memory E*a

The I6K uses 4 Up; Static Ram and oeJl using the Static J?T* speed low power^i the computer, which comes to ju where Position ii*t

64K Memory

AJf the above inf^ advantage lies in 56 K of usable me*} the use of other ^ 8192-65536 The & Spectrum Mem<Y Upgrade your Sp£ri it is simply slipped15 are supplied, and^ time. The fitting rjL same as Sinclair's^

NOTE

The case can be purchased separately with the keyboard aperture uncut, so rf you have one of our early uncased keyboards, or m fact any other suppliers' keyboards, these could be fitted The keyboard is connected to your computer by a ribbon cable and this has connectors fitted which simply push into the Sinclair connectors It is a simple two minute job and requires no electronic skills This keyboard does not need any soldering Please specify on order whether you require the ZX 81 or Spectrum case

SPECTRUM MODEL

SPECTRUM LIGHT PEN

This is supplied with spectrum legends, and a slightly different base for fitting the spectrum msjde. again all the connectors are at the rear of the case and there is plenty of room for the power supply (and other add-ons) Should you want to change, we can supply both the Spectrum legends and details of updating your case which will enable modification from the ZX 81 to spectrum PLEASE specify on your order whether you require the ZX 81 ex spectrum case

KEYBOARD (SPECTRUM/81 )

The pen enables you to produce high resolution drawings on your own televi¬ sion set. saving a vast amount of time over using basic program¬ ming statements, such as Plot, Draw etc. You can erase, modify and save drawings and it comes complete with software program The superb fight pen is available from D K tronics.

$49.95

	* ,,rXZVta’.. •
i-^-i	1 1 il Ill'll Li r1
	.

Internal fixing for ZX 81 keyboard case.

r - ■ i	in niimimin * i
i < i i "" i L. . J	-T iira
Internal fixing for spectrum keyboard
case.

4a

TIMEX SINCLAIR USER /une 1983

SPECTRUM/81 TOOLKIT

This is the toolkit which won acclaim in the feature in the August 1982 issue (pages 29 and 30) of Sinclair User "ft is the most impressive program, fast in execution with clear and full instructions , it stands out from the rest of the field. " The ZXED is a powerful editor for use on the expanded ZX81 . ft is intended for use by the serious BASIC programmer and offers several useful and time saving features most helpful during all stages of program development. The facilities provided are as follows ALTER, BYTES, COPY, DELETE, FIND, HELP, INSERT, KEEP, MOVE. RENUMBER AND VERIFY The Spectrum Toolkit contains most of the features above plus autofme numberer and append, and will run in the 16K and 48K spectrum.

Both at

only $12.95

FLEXIBLE

RIBBON

CONNECTOR

ff you have ever had whiteouts or system crashes this could be the answer. It stops the move¬ ment between the computer and the RAM expansion, it is supplied with a ribbon, 6 inches long, witfi a male connector at one end and a female at the other, at only

$35.95

4K GRAPHICS ROM $44. 95

The DK Graphic module is our latest ZX 81 accessory This module unlike most other accessories fits neatly inside your computer under the keyboard The module comes ready built, fully tested and complete with a 4K graphic ROM Thrs will give you an unbelievable 448 extra pre programmed graphics, your normal graphic set contains only 64 This means that you now have 512 graphics and with their inverse 1024 This now turns the 81 into a very powerful computer with a graphic set rarefy found on larger more expensive machines In the ROM are lower case letters, bombs, bullets, rockets, tanks, a complete set of invaders graphics and that only accounts for about 50 of them, there are still about 400 left (that may give you an idea as to the scope of the new ROM] However, the module does not finish there, it also has a spare holder on the board which will accept a further 4K of ROM/RAM Thrs holder can be fitted with a JK/2K/RAM and can be used for user definable graphics so you can create your own custom character sets

WHY WATT?

ORDER TODAY FOR FAST DELIVERY

16K Memory $43 9S 1(iK juncAied; fj JL« 64W Memory ftJSOQ 64K|uniaied| f 112 QQ

16/64 MEMORY FORZX81^H

The above illustration shows the casing for the I6K or massive 64K

I'UM MEMORY

t mansion $41.50

b Dynamic Ram Chips. We use the dynamic as they are much denser than :i :upy less space. They are also much cheaper than the equivalent product c im. The Ram is manufactured with high quality materials, and uses hrgh i fams. It is supplied ready-built and only needs to be plugged into the rear of II the components are fitted into holders, Thrs massive add-on memory / ou full y assembled and tested is the cheapest 1 6K memory available any* r memory from 16384 to 32768, (Same as the Sinclair memory ,)

T6K (UNCASED) $35.95

K pension $135.00

z rmation on the I6K also applies to the 64K Memory Expansion, but the t he 64 K giving nearly FOUR times the memory. This advanced model has r nory. In addition, the block from 8K to J6K can be switched out to enable h Jdons. The graphics ROM is to be used in this area. Positron in Memory. E l*0Ck From 8192-1 6384 is switchable 64K (UNCASED)$TJ2.00

□ ry Expansion $54.00

? pum to 48K of user Ram. The Spectrum memory expansion is simple to fit, nside the case, and then only requires plugging in. Full fitting instructions :he only tool you will need is a screwdriver and just two minutes of your e quires no electronic skills. Position in memory from 32768 to 65536, (The i jpgrade to 48 KJ,

| Plrav statf type of macron*, which Rom memory we. quantity and pi,Ke when ofdenng

Pfease send me . . . @

Please send me .

Please send me . . _ _ _ _

Please add on $ 9,00 for P/P

In enclose cheque/P.G. payable to DKTronics total E. . .

or debit my Acte ss/Ba re iaycard [_

Mastercard

Signature .

Send to DK Jronics Ltd, Unit 2, Shire Hill tnd £ sr, Saffron Walden Essex C07I 1AQ England.

Tel: { 0799 ) 2203b { trade enquiries please telex 81653 attn. DK)

cft'tronks

TIMEX SINCLAIR USER June 1983 For more information t circle 19 on reader service cord.

| iNci* colour brochure now JvtiUble, send 1 1.00 tor quick return _ j

ion. rirrlf* on render servire rrnrrf. 49

register that for port B, and register B that for port A. Register C con¬ tains the I/O location of the three ports and the Control Location. Register DE is used as a counter to pause for longer than 50ms — when following the machine code routine, it is useful to look at table one.

The timer has to last for 50ms, so an electrolytic capacitor is used. Because they have tolerances bet¬ ween plus 100 percent or minus 50 percent the pre-set is made very large to take account of it. If elec¬ trolyses are used, the timer should be set up on an oscilloscope. If an oscilloscope is not available, tan¬ talum capacitors should be used in¬ stead. Alternatively, it is possible to feed the Q output temporarily to the port A input — any will do — and write a small program to measure the duration of the output pulse,

Table 1		2516.2K by 8-bit
	EPROM function	Nothing	Read Program
PCD	A8	—Standard	Address Inputs
PCI	A9	—Standard	Address Inputs—
PC2	A10	—Standard	Address Inputs—
PC3	Not used
PC4	PD/PGM	Low	Low Pulsed high
PCS	Not used	—	— —
PC6	CS	High	Low High
PC7	5v/26v	High	High Low
	2352,4 K by 8-bit
	EPROM function	Nothing	Read Program
PCO	AS	—Standard	Address tnpu ts—
PCI	A 9	—Standard	Address Inputs—
PC2	A10	—Standard	Address Inputs—
PC3	All	—Standard	Address Inputs—
PC4	Pd/PGM	Low	Low Pulsed high
PCS	Not used	High	Low High
PC6	CS	—	— —
PC7	5v/26v	High	High Low

Figure 5; Detail of wiring on small board

oooo ooooo o o o o o ooooo ooooo

OOOOOI

o o o

O OJ1

OOGOOOOOOOOOOl OOOOOOOOOOOOOl OOOJOOOOOOOOOI OOOOOOOOOOOOOl OOOOOOOOOOl O O I

OOOOO

ooooo o o ^ o c ooooo ooooo ooooo Aoooo

oooo

OOOO

oooo

OOOO

oooo

oooo

OOOO

O O O O O O I O O O O O o 1 O O O O D O < OOOOOOl OOOOOOl OOOOOOl OOOOOOl

Figure 6: Main circuit diagram

ZJ£81 EDGE CONNECTOR

+26 ¥

50

Components

1 x INS8255 ( 1 C 1 >

1 x 741 32 (1C 2)

1 x 74LS32 MC 3)

1 x 74LSOOOC4I 1 x 7805 (IC5) 5v I A regulator 1 x BD235ITR 1)

1 x BC108CTR2)

3 x IN 4002 1 xBZY88 24V Zener 1 x BXY88 SVZener 3 x IN4 1 48

2x470 ^-F 63V electrolytic 1 x22G0/r-F 1 6V electrolytic t x 1 0*/-F 1 0V electrolytic 1 x 1 /j-F 63 V tantalum 3 xO.1 Polyester 1 x 4 7 K ohms Preset Resistor 1 x 5K6 ohms V2w 5% Resistor 1 x 4 K7 ohms Vzw 5% Resistor 1 x 2X7 ohms V?w 6% Resistor 1 x 2 pole change-over switch 1 x 40 pm DILsocket 1 x 24 pm zero force socket 1 x 9-0-9V 1 amp transformer 1 xcase 1 6 cm. x 1 0cm. x 6cm.

Veroboa rd— VQ boa rd Verowire

1 2in ribbon cable— 20-way Nuts and bolts

Cassette-type chassis plug and free socket Connecting wire— single plus twin mams 23-way double-edge connector 23-way double male-male PCB

10© PRINT L,UHPT A0DRE55 IN THE EPROMIB

110 INPUT V

12© REM 3 MSB NEED TO BE R L0GI C 1

130 LET Y=rY+5^3^t-t

14© POKE lb514 j Y-256+INT (Y/aS6

IS© POKE 16515 jINT fY/256)

160 PRINT "ENTER NO OF BYTES TO BE SENT"

170 INPUT R 1S0 DIM B t R )

190 FOR C^l TO R 200 INPUT B(C1 210 PRINT 6(C)

223 NEXT C 230 FOR C=1 TO R 24-0 POKE 16516 , B ( C 3 25© LET 5=U5R 1651©

260 IF PEEK 16516 OPEEK 16517 T HEN GOTO 1000 270 LET Y =Y +1

2B0 POKE 165 14|Y —256* 1NT CY^256

230 POKE 16515 ^ I NT

I T /dODl

300 NEXT C 310 PRINT "JOB FINISHED,. NO ERR ORS "

320 PRINT "DO YOU REQUIRE TO PR OGRRH MORE DRTR IN"

330 INPUT Z*

34.0 IF Z*="Y" THEN GOTO 100 3S0 STOP

1000 PRINT "ERROR HRS OCCURRED" 1010 LET Y =Y -5734.4

£2INT "ERROR OCCURRED RT '* : Y 1030 PRINT "DRTR RERD FROM THIS LOCATION 15 " ; PEEK 16517 104.0 STOP

Figure 8: Cut track on back of large board

Machine Code Table