ZX Format #01: Hardware Modifications for Scorpion ZS-256

Vladimir Larkov presents: blocking port #1FFD on Scorpion ZS-256. The material is prepared specifically for the St. Petersburg electronic magazine "ZX-Format". Reprinting and distribution of this article in other magazines, electronic networks, and other mass media (provided the full volume of the article is preserved) is only welcomed by the author.

We present to your attention a simple modification of the "Scorpion ZS-256" computer board that will significantly ease the life of its owners. Recently, there has been a sufficient number of programs whose authors address the port by half the address, using the command OUT (#FD), A to switch pages. Such programs refuse to work on "Scorpions," as the "Scorpion" requires the full port address. This modification allows such programs to run. It blocks port #1FFD, thus allowing OUT (#FD), A to pass and making it possible to use programs like STS, watch "SATISFACTION," or "INSULT" without modifications.

One should only remember one thing - programs that use the button, such as "TASM," which access the ROM via RST 8, will not work, as RST 8 is under the control of the shadow, which requires page 8 to operate, and, naturally, port #1FFD. So, now in more detail: the button can be pressed at any moment, while in boot or the program itself, but it should not be pressed while in the main menu of the computer, as the shadow also "operates" there. So, for example: you need to run STS - go to TR-DOS, press the button, run the program RUN "STS". You are surprised to see that the program works!!! Or, even simpler - press "ENTER" in the main menu, exit to TR-DOS with boot loading, press the button, run the program. The only boot I know that does not get along with the button is the old boot by Trubinov (probably uses RST).

Secondly - the fact that the button is pressed does not prevent you from using the shadow!!! When the "magic" is pressed, port #1FFD is unlocked and you will easily find yourself in your favorite shadow. The second control signal for unlocking the port is, of course, "reset." That is, upon "reset" or "magic," the computer returns its port or extra pages.

Thus, another plus is revealed - the button allows you to "fool" the protections from the "Scorpion," which are based on randomly filling the 8th page with junk. And although this effect was not taken into account when designing the modification, it is another argument in favor of the modification. Now - the schematic:
========================================
Remove pin 1 of D49 from the track (without breaking the track itself!)
Cut the conductor between 13(D53) and 15(D52).
┌───────────────────────┐  
1(D49) track   │  
__│_ └────┘
\   /
_\ /_ LED                          
10 kOhm     /9(TM2)┌────┐    │/──────┤    ├────┤   KT315      └────┘    │\                  
\ emitter                   │                   
│                  ─┴─ Soldering this, you will never get confused - with the blocking on, the LED lights up, when off - it does not.

In conclusion, I would like to dispel the doubts of the indecisive - I installed this modification more than two years ago, and during all this time not a single minus has been identified - after all, as long as you do not press the button, the modification does NOT affect the computer's circuit AT ALL, changing it NOT ONE BIT.

With best wishes, Vladimir.
St.-Petersburg, 23-Oct-1995.
end of file

Contents of the publication: ZX Format #01

• IS-DOS
  IskraSoft introduces IS-DOS Classic 4.0 with advanced text editing features, a disk utility, a hard drive controller for ZX Spectrum, and a program debugger.
• IS-DOS - Владимир Елисеев
  Overview of IS-DOS for ZX Spectrum, highlighting its advantages over TR-DOS. Discussion on installation, usage, and file management features of IS-DOS. Introduction to system utilities and interface similar to Norton Commander.
• IS-DOS - Владимир Елисеев
  The article provides a concise guide to the IS-DOS system disk, listing all essential files with explanations. Files are sorted alphabetically and grouped by directories for easy navigation. The guide focuses on a basic overview of files and commands without extensive descriptions.
• IS-DOS - Владимир Елисеев
  Discussion on the UniColor standard for color settings in IS-DOS programs, its implementation, and advantages for user customization.
• IS-DOS - Владимир Елисеев
  Discussion of IS-DOS window interface features. Implementation of window system in IS-DOS and its advantages. Example programs for creating windows and frames.
• IS-DOS - Владимир Елисеев
  Description of the internal workings of the gmen.com program for IS-DOS, focusing on device management and menu handling with detailed source code and comments.
• Hardware - Vladimir Larkov
  Discussion on modifying Scorpion ZS-256 hardware for compatibility with specific software. Describes blocking port #1FFD to run incompatible programs. Provides technical details for implementation.
• Железо - Nemo
  Discussing hardware braking devices for ZX Spectrum. Focus on creation and impact of brakes on overclocked processors. Warning about potential side effects.
• Железо
  Discussion of the impracticality of repairing old computers and the economic sense in replacing them with modern hardware. The article highlights challenges in DIY repairs and suggests alternative solutions. Emphasizes the benefits of upgrading to newer, more reliable components.
• Железо
  Discussion of new peripheral developments for Scorpion ZS 256, including an innovative universal controller and MIDI interface. Highlights enhancements in keyboard and mouse controllers and expansion of built-in software capabilities. Offers details on professional ROM extension and turbo mode for improved performance.
• Игрушки - Ruster
  A detailed walkthrough of the game Crystal Kingdom Dizzy, including solutions to puzzles and tips for progressing through the story.
• Игрушки - Павел Рындин
  Description of the logic game 'Bulls and Cows', its mechanics and gameplay. Explains levels of difficulty and the goal to guess a number with minimal attempts.
• Игрушки - Вячеслав Медноногов
  Discussion on the nuances of 'UFO: Enemy Unknown' game, focusing on alien species, their tactics, and gameplay strategies. Details on game mechanics and future sequel 'UFO-2: Devils of the Abyss'. Includes programming insights and development history.
• Игрушки - SParker
  Overview of games and software on the Saint Petersburg market in 1995.
• Интервью
  Vyacheslav Mednonogov shares his journey as a programmer, from assembling his first Spectrum-48 to developing notable games like 'UFO. Enemy Unknown'. He describes challenges and insights in game development and the rise of Russian game localization. His experiences highlight the evolution of programming and software distribution in the 1990s.
• Информация
  Introduction to ZX-Format, a new electronic magazine for ZX Spectrum enthusiasts, focusing on games, programming, hardware, and community interaction.
• Конкурс
  Discussion on organizing a new competition for the magazine. Readers are invited to submit their theme ideas. Selected themes will be featured in future issues.
• Конкурс
  ZX Format announces a competition for the best mission created using the mission editor for the game Laser Squad. Submissions are accepted by mail or in person. Winner receives a box of 3M disks and the next issue for free.
• Отдохнём - Килат Амор
  A programmer's day filled with dreams, gaming, and casual conversations. Vasetchkin balances ambition with relaxation, embodying the programmer's spirit. Reflects on the demands and enjoyment of a programmer's life.
• Mailbox - Максим Романов
  Discussion on hardware and software offers in St. Petersburg by LOGROS and Create Soft, including detailed insights on Kempston Mouse interface.
• Mailbox - SParker
  Compilation of cheat codes for ZX Spectrum games by Sergey Pavlov. Techniques for extra lives and immortality. Not recommended for fans of fair play.
• Mailbox
  Description of submission guidelines for letters and articles to the magazine, including formatting and submission preferences.
• Премьера - Алексей Щекин
  Gameplay of Lines game on ZX Spectrum, similar to Color Lines. Move balls to form lines of the same color. Scoring and controls are described.
• Программистам - Дмитрий Рудовский
  Introduction to advanced BASIC programming techniques for ZX Spectrum 48, highlighting its advantages over 128 BASIC. Plans for future articles include service programs and language extensions. The article serves as a guide for experienced programmers.
• Программистам - Михаил Спицын
  Introduction to assembly language on ZX Spectrum. Explanation of Z80 processor structure, registers, and basic commands. Includes example programs for learning.
• Программистам - Андрей Седов
  Mission editor for Laser Squad by Andrey Sedov allows fans to create new missions. Includes user-friendly interface with minimal controls. Offers features like object editing, price adjustments, and sprite assignment.
• Various
  History of Amiga computer development, its creators, and key features. Evolution from arcade games to a leading home computer. Amiga's market success and technological advancements.
• Разное
  Review of upcoming ZX Spectrum software products with demos. Highlights include adventure games, RPG trials, and strategic tactics. Several well-known developers contribute to these releases.