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  • Tandy's Little Wonder, The Color Computer

    1979-1991 A complete history and reference guide to the CoCo and all

    related hardware, software, and support sources. by F.G. Swygert

    published by FARNA Systems "the FARNA Fox!"

  • page 4 Tandy's Little Wonder

    In the course of writing, some standards were set so as not to confuse the reader.

    * Hardware modifications, upgrades, and repairs are referred to throughout this book. At times, the references given may not seem clear. They are written in such a way that a person with some understanding of electronics and the CoCo can easily figure out what to do. If you do not understand the directions, you probably should not at- tempt the operation alone... get help! THE AUTHOR, PUBLISHER, NOR PRINTER ARE RESPONSIBLE IN ANY FASHION FOR THE RESULTS OF ANY PROJECTS OR REPAIRS MENTIONED IN THIS BOOK, TO INCLUDE BODILY HARM, LOSS OF EQUIPMENT, OR LOSS OF DATA!

    * All references to hexadecimal addresses are written as &Hxxxx. The &H is used to precede the actual hexa- decimal value when poking into memory to let the computer know the value will be in hexadecimal. Some other texts use a dollar sign ($) in front of a value to mark it as being hexadecimal, others use an asterics (*) or dont mark it at all, as eight bit hexadecimal values usually contain numbers and letters.

    * When Radio Shack lists an item mentioned in their catalog (especially parts), the part number will be listed in parentheses. This is not to encourage patronage of Radio Shack, but there is a Radio Shack in or near almost every town across the U.S. One would be better served to find an electronics parts store with a better small parts stock then RS, or mail order parts from one of the following:

    All Electronics Corp. P.O. Box 567

    Van Nuys, CA 91408 Order phone 1-800-826-5432, call for catalog. Minimum order is $10 plus $3.50 shipping and handling.

    Mouser Electronics 2401 Hwy 287 North Mansfield, TX 76063

    Phone 817-483-4422, call or write for catalog.

    Digi-Key Corp. P.O. Box 677

    Thief River Falls, MN 56701-0677 Order phone 1-800-344-4539. No minimum order, mini- mum shipping charge of $5 (no shipping if order over $25). No Motorola chips listed, but will supply non-listed items if available. Volume discounts for orders over $100.

    writing conventions used in this book.... Jameco Electronics 1355 Shoreway Road Belmont, CA 94002

    Order phone 415-592-8097, call for catalog. $20 minimum order plus 5% shipping and handling. Catalog usually has some IC pin-out information and RAM/EPROM cross ref- erence... good reference source.

    * The following abbreviations are used: A/L - Assembly Language ANSI - American National Standards Institute ASCII - American Standard for Computer Information In- terchange BASIC - Beginners All-purpose Symbolic Instruction Code BPS - Bits Per Second CCx - Color Computer, x = 1, 2, or 3 CMOS - Complimentary Metal Oxide Silicon (chip con- struction) CoCo - Color Computer CPU - Central Processing Unit (actual processor chip) DECB - Disk Extended Color BASIC DOS - Disk Operating System DRAM - Dynamic RAM EDTASM or EDT/ASM - Editor/Assembler, usually the Tandy product EMAIL or E-Mail - Electronic Mail EPROM - Electronicly Programmable Read Only Memory GIME - Graphics, Interrupt, Memory Enhancement (chip, in CC3) GUI - Graphic User Interface IC - Integrated Circuit (a chip) I/O - Input/Output M/L - Machine Language MPI - Multi-Pak Interface MS - Milli-Seconds (millionths of a second) MS-DOS - MicroSoft Disk Operating System NMOS - Negative Metal Oxide Silicon (chip construction) OS - Operating System OS-9 - Operating System (for the 680)9 PIA - Peripheral Interface Adapter PCB - Perforated Circuit Board P/S or PS - Power Supply RAM - Random Access Memory, usually meaning DRAM ROM - Read Only Memory RS - Rat Shack... er... Radio Shack (division of Tandy Corp.) SAM - Synchronous Address Multiplexer SECB - Super Extended Color BASIC SIG - Special Interest Group SP - Slot Pak (also used for Slot Pak II) VDG - Video Display Generator VOM - Volt and Ohm Meter (multimeter) WYSIWYG - What You See Is What You Get

    (and probably others not listed!)

  • Tandy's Little Wonder page 5

    Alfredo Santos, December 1990 While skimming through the pages of a popular Color Computer magazine recently, my thoughts traveled back through the 12 years of Color Computer history. Back to a time when there was NOTHING. I recalled the events leading up to my introduction to this wonderful machine. It seems like only yesterday...

    Christmas morning 1980: Pam, my wife, must have known that I was very interested in getting a computer because, there, under the tree was the new Mattell Intellevision!? Pam bought that machine due, in part, to the computer capabilities the unit would have with a keyboard console, scheduled for release in the spring. After several days of gunning down waves of aliens, we both suffered from blurred eye sight, blistered fingers, lack of sleep, and video game burn out. Spring seemed so far away.

    A couple weeks after Christmas, I came across an ad in the New York Daily News for a new Radio Shack computer which, like the Intellevision, had game cartridge capabilities, an important feature because, if I didnt like computing, I could always go back to cleaning up the galaxy. For the refund price of the Intellevision (sorry Pam) plus another $150, I had enough money to purchase the new TRS-80 Color Computer. I celebrated the arrival of an early "spring". It was January 9th, 1981. It seems like only yesterday.......

    This project was, to say the least, a labor of love. Every attempt was made to ensure an accurate account of the Color Computers evolution. Extensive use of various computer magazine articles and ads were used as the basis for "dating" events. This "dating" method was used because most of us probably heard about various developments through these sources. Keep in mind, however, that sometimes ads can precede product availability by as much as a month or more. Those of you who ordered the very first "Super 'Color' Writer" program from Nelson Software know what I mean. Other information sources included printouts and files from old bulletin board sessions, telephone interviews, and correspondence with various users.

    Before starting, let me just say that, while looking through the numerous back issues for Color Computer information, a strange thing started happening. Remember that frustrated feeling, of the early years, when YOU looked for Color Computer information and none could be found? It all started coming back to me.......

    Francis G. Swygert, March 1993 Al graciously allowed me to use his existing text which was written for submission to The Rainbow Magazine. Rainbow decided not to print it, so Al released it to the public over Delphi (a major computer database). Als format and style were used pretty much intact for the history portion of this book, though heavily edited and added to in places by myself. The original text only went up to June of 1986. All history text after that date and all additional information was written by myself (except where noted). Many thanks goes to Al and the other contributors! I can also echo Als opening statement: this project was definitely borne out of a love for the little computer we affectionately call CoCo..

    It is also important to remember just how this text is written. This was not intended to be a definitive history. Indeed, it is the authors belief that the CoCo is far from being relegated to history as of yet. Instead, the history portion is more of an overview of what has happened in the life of the CoCo over the years, almost a "time line" type of chronology. The entire book itself is a complete CoCo reference book... the "CoCo bible", so to speak..

    Dont let the past tense used in the text fool you. It was deemed the best way to present the majority of the history and was used throughout for uniformity. Many of the later products were still available and supported by the authors and distributors at the time this was written. They simply dont get enough response to maintain advertising costs. So go ahead and write- ask for information! The only cost will be a stamp- is that to much for your CoCo?

    Introduction...

  • page 6 Tandy's Little Wonder

    CoCo History From Birth to the Present...

    HOW THE COCO WAS BORN: The initial Tandy/Motorola connection occurred sometime in the mid-70s when the two were invited by the U.S. National Weather Service to assist in developing a "weather radio" system. In 1977, a year after starting talks with Motorola about the possibility of designing a low-cost home computer that could be hooked up to a regular TV set, Tandy was invited to participate in an agricultural experi- ment. Project "Green Thumb", as it was called, would employ information retrieval to give farmers data, updated hourly by computer. Terminals used in this project were developed by and sold by Radio Shack in conjunction with Motorola. Terminals were distributed to 200 farms in Shelby and Todd counties, Kentucky. The "Green Thumb" network was spon- sored by the National Weather Service, U.S. Department of Agriculture, and the University of Kentucky.

    By late 1977, Motorolas' MC6847 Video Display Genera- tor chip was developed. Although it was unclear if the VDG came about because of project "Green Thumb" or Tandys' search for the "low-cost" home computer, in 1978, when it was married to the MC6808 CPU,