NO. 35 $2.00 APRIL 1981 'ErI . : 3 f ; l i T 'flj iEJKUOFHH 2 :TKBflRLE3 : 0 3 3 ^ 3 5 » J : H T O Q The Perfect Fit The Micromodem II data communications system The other part of the Micromodem II datacomm and the Apple II* computer. What better combination to system is a Microcoupler which connects the maximize the capabilities of your personal computer! Micromodem board and Apple II to a telephone line. This popular direct connect modem can transmit The Microcoupler gets a dial tone, dials numbers, data between an Apple II and another Apple II, a answers the phone and hangs up when a transmission terminal, another microcomputer, minicomputer or is over. There are none of the losses or distortions even a large time-sharing computer anywhere in North associated with acoustic couplers. The Microcoupler is America. The Micromodem II has unique automatic compatible with any North American standard dialing and answer capabilities which further increases telephone lines and is FCC-approved for direct the communications possibilities between the Apple II connection in the U.S. It works with standard dial and another computer or terminal. phone service orTouch-tone service. You can send and/or receive messages or data The Micromodem II is completely compatible with when you are out of your office, home or out of town. Bell 103-type modems. Full and half-duplex operating Your branch business locations can communicate with modes are available as well as speed selectable each other regarding inventory and other matters over transmission rates of 110 and 300 bps. the phone. Or you can communicate with friends Why not increase your Apple M’s capabilities by across the country. And you can access information outfitting it with the sophisticated Micromodem II data utilities like the SOURCE for various business and communications system? The Micromodem II is personal applications. available at retail computer stores nationwide. For the The Micromodem II consists of two parts. One part store nearest you, call or write: includes the printed circuit board which holds the Micromodem II, ROM firmware and the serial interface The board plugs directly into the Apple II providing all the functions of a serial interface card plus ©Hayes programmable auto dialing and auto answer Hayes Microcomputer Products Inc. capabilities. The on-board ROM firmware enables the 5835 Peachtree Corners East, Norcross, Georgia 30092 (404) 449-8791 Micromodern II to operate in any of three modes to ™ Micromodem II Is a trademark of Hayes Microcomputer Products, Inc. perform different tasks-terminal mode, remote console ^ 'Apple II is a registered trademark of Apple Computer Inc. and program control mode. The Micromodem II can also be used with the Bel* & Howell computer. ■ MADE IN USA hook c Up to 5 million bytes of on-line storage ...... _ floppies. And, without stealing power from your Apple II*! Your business is more complicated Technically Inclined? than anyone realizes. Or, you’re The card operates under Apple DOS growing faster than expected. Does 3.1 or 3.2, with 48K Apple II. It has full that mean you have to trade in your compatabllity with mini-disks. Handles reliable Apple II for a bigger, more from one to four 8” floppy drives. costly system? Or, is there a simple, Single or double density disks use reasonable solution? DMA transfer techniques . with ou bet there is, now that Programma high speed transfer of half million International has introduced the bits per second. Teeter Electronics PRODISK control­ ler card. Priced Right The amazing PROOISK controller PRODISK is like having the storage card is priced at $645.00. And it’s capability of ten Apples! Because a tax deductible business expense. with just four 8" floppy disk drives, its Its low price works out to be even on-line storage capacity goes to a lower! Same for the special business-slze 5 million bytes. Plus it Programma 8" floppy disk drives delivers high-speed transfer of a half (800 or 850 Shugart equivalent). PRODISK million bits per second. Example: two single sided drives, With storage and speed like that you priced at $1549.00. can really get a handle on your entire Get big business storage capacity business. And, It won’t Interfere with for your small business right now your Apple's operation. You see, the . with PRODISK, available at new PRODISK card Is powered from your better computer stores, or the drives, not the Apple. Since there’s direct from Programma Inter­ no significant power drain, other national. cards can be used with no problem. B ig power for small business ernational ln< Naomi Street C A 9 1 5 0 4 2 4 0 and Apple DOS are trademarks of Apple Computer, Inc. No. 35 - April 1981 MICRO - The 6502 Journal 1 A BRILLIANT FUTURE FOR YOUR AIM-65 WITH THE BANKER MEMORY : i Your 36K of free address spac,e is the AIM's most valuable and limited re­ source. With today's large capacity RAM boards, ROM boards, disk systems, video boards, and other expansion accessories it is easy to deplete this resource before the applica­ tion requirement is satisfied. MTU has solved this problem. THE BANKER MEMORY contains 32K of RAM, 4 PROM sockets for 2716/2732/2332, a PROM programmer, 40 bits of parallel I/O, and 4 timers from two 6522 I/O chips. Addres°sing is extremely flexible with the RAM independently addressable in 4K blocks, PROM's independently addressable, and I/O addressable anywhere on a 64 byte boundary (even in AIM’s I/O area at AXXX by adding a single jumper to the AIM). This may sound familiar, but read on! Unlike other AIM compatible memory boards, THE BANKER MEMORY has on-board bank- switching logic! The four 8K blocks of RAM plus the 4 PROM sockets make up 8 resources, each associated with a bit in an Enable Register. Through this Enable Register resources may be turned on and off under software control. When a resource is off, its address space is freed for other uses. You can even put BANKER resources at the same address and switch among them for virtually unlimited RAM and PROM expansion! You can even have multiple page zero's and stacks! Do you need 160K byte of memory? It only takes 5 of THE BANKER MEMORY boards and you end up with 5 page zeros and stacks to boot! There’s more! The BANKER MEMORY also incorporates 18 bit addressing which allows for the 256K address spaces of the future. RAM, PROM, and I/O each has its own full 18 bit address decoder which allows these resources to be in different 64K banks. This board and other MTU products, such as our 320 by 200 dot VISIBLE MEMORY and Floppy Disk Controller with 16K DMA RAM, can turn your AIM into a truly powerful 6502 computer that far surpasses the packaged systems in functional performance. INTRODUCTORY SPECIAL K-1032-1 32K BANKER MEMORY FULLY ASSEMBLED AND TESTED $395.00 ($450.00 as of March 1, 1980) or the K-1032-2 16K RAM only with bank switching and 18 bit address bus only $295.00 Isn’t it time you took a closer look at MTU — we offer you power now with an eye to the future. WRITE OR CALL TODAY FOR OUR 48 PAGE FALL 1980 6502 CATALOG International requests include $1.00 VISA and MASTERCARD accepted Photo credit: l l l l Micro Technology Unlimited l l l l 2806 Hillsborough Street SUPERNOVA CRAB NEBULA: P.O. Box 12106 Palomar Observatory, Raleigh. NC 27605. U.S.A. California Institute of Technology {919) 833-1458 NO. 35 APRIL 1981 THE 6502JOURNAL STAFF Editor/Publisher ROBERT M. TRIPP CONTENTS Associate Publisher RICHARD RETTIG - S-C ASSEMBLER MODIFICATIONS Associate Editor I Enhance the usefulness of the S-C assembler for the Apple MARY ANN CURTIS By Ned W. Rhodes Special Projects Editor . o PRINT USING FOR THE PET MARJORIE MORSE \ o Popular program adapted to run on any PET or CBM machine Art Director By David Malmberg GARY W. FISH . - MEMSEARCH FOR THE AIM 65 Typesetting 1 / Scan through memory using this machine language utility program EMMALYN H. BENTLEY By Bob Kovacs Advertising Manager JOYSTICKS FOR THE OSI C4 L. CATHERINE BLAND C.O Make your own joysticks Circulation Manager By Charles Platt CAROL A. STARK 0 _ APPLE MEMORY MAPS, PART I MICRO Specialists C . f Draw your own memory maps and display them APPLE: FORD CAVALLARI By Peter A. Cook PET: LOREN WRIGHT O T SYM TIME-REMAINING TIMER OSI: PAULGEFFEN 0 ( Measure elapsed time and create an “alarm” for your SYM Comptroller By Ralph Orton DONNA M. TRIPP . 0 OH NO — IT’S GARBAGE COLLECT! Bookkeeper Find out what garbage collect is, and how to avoid it KAY COLLINS By Gordon A. Campbell „ ADD A LIGHT PEN TO YOUR MICRO 0 1 Hardware details to install a light pen on any 6502 W C ftO jS published monthly by: MICRO INK, Inc., Chelmsford, MA 01824 By Peter Alan Koski Second Class postage paid at: Chelmsford, MA 01824 and additional INTEGER BASIC INTERNALS offices O O A sorted list of Apple Integer BASIC memory locations Publication Number: COTR 395770 ISSN: 0271-9002 By Glenn R. Sogge ATARI ERROR MESSAGES Subscription Rates: Per Year 0%7 English language versions of Atari’s number-coded error messages U.S. By David P. Allen through March 31 $15.00 thereafter $18.00 _ n BASIC PROGRAM CONVERTER BETWEEN SYM AND KIM Foreign surface mail $21.00 Air mail: / y Transfer BASIC programs from SYM to KIM, and vice versa Europe $36.00 By Lee Chapel Mexico, Central America $39.00 Middle East, North Africa $42.00 South America, Central Africa $51.00 DEPARTMENTS South Africa, Far East, Australasia $60.00 5 Editorial — Robert M.