Schlagwort: Retro Computers

  • Adding a turbo readout to a vintage PC case

    Adding a turbo readout to a vintage PC case

    Reading Time: 2 minutes

    If you are young, you may not remember the turbo buttons of the 1990s. These existed for backwards-compatibility with older games and software that wouldn’t run properly at the blazing-fast processor clock speeds of the time. The turbo button simply told the CPU to run at a slower clock speed that would work with that older software. Joshua Woehlke uses an old PC with a 486 processor and decided to add his own useless turbo readout to complement the turbo button.

    Woehlke’s computer uses a vintage ATX case from the ’90s that does, in fact, have a turbo button. But that case lacked the kind of clock speed readout that was popular when it was new. Those readouts were usually three-digit seven-segment displays and the implication was that they would show the processor’s current clock speed. Except that was all a farce and, in reality, they just switched between two preset numbers: one for the faster speed and one for the slower speed. Woehlke’s project mimics that non-functionality.

    The hardware for this project includes an Arduino Mega 2560 board and a small OLED screen. Woehlke chose the Mega because he had it on hand, but any Arduino board would have worked. The Arduino receives power from one of the power supply’s 5V rails. And like the real turbo readouts of the ’90s, the Arduino doesn’t measure clock speed at all. It just looks at the LED above the turbo button to see if it is active, then uses that state to determine which number to display on the OLED. For extra flair, Woehlke added a starfield “screensaver” that appears on the OLED 10 seconds after pushing the turbo button.

    The post Adding a turbo readout to a vintage PC case appeared first on Arduino Blog.

    Website: LINK

  • Use Excel to load Commodore 64 software

    Use Excel to load Commodore 64 software

    Reading Time: 2 minutes

    Loading software on a vintage computer, such as a Commodore 64, is a pain. Early eight-bit computers almost never contained any onboard persistent storage, so users had to load software from external media like cassette tapes. To make retro computing far more convenient, RaspberryPioneer developed a method for loading Commodore 64 software from Microsoft Excel.

    This workflow starts with a modern computer running Microsoft Excel. RaspberryPioneer created an Excel spreadsheet that acts as a database of Commodore 64 software, linking to the ROMs and containing information such as specific load commands. The spreadsheet integrates Visual Basic for Applications (VBA) programming, so the user can select a software entry and then launch it. Doing so sends that software’s ROM data to the Commodore 64, which loads the software like it came from conventional media.

    RaspberryPioneer’s workflow relies on a 5V Arduino board to act as an intermediary between the modern computer and the Commodore 64. The Excel VBA script sends the selected ROM data to the Arduino via a USB serial connection. The Arduino then, in turn, sends the data to the Commodore 64 through a hardware serial connection. That requires a Commodore serial cable, with the standard plug at one end and the other end connected to the Arduino’s pins.

    Anyone that frequently uses a Commodore 64 would benefit from adopting RaspberryPioneer’s workflow to load software.

    The post Use Excel to load Commodore 64 software appeared first on Arduino Blog.

    Website: LINK

  • Experiment with ’80s graphics using this breadboard setup

    Experiment with ’80s graphics using this breadboard setup

    Reading Time: 2 minutes

    Experiment with ’80s graphics using this breadboard setup

    Arduino Team — April 19th, 2022

    Before standardized video cards came along, computer and video game console designers utilized video chips. Those simplified the design process and offloaded much of the work from the processor. Those video chips had hardcoded graphical building blocks and handled video generation. One of the most popular was the Texas Instruments TMS9918 used in the ColecoVision, TI-99/4, and MSX computers. This write-up from Doctor Volt will walk you through how to use an Arduino Nano to output graphics from the TMS9918.

    You can follow this tutorial with just a breadboard, a TMS9918 VDP (video display processor), and a handful of compatible DRAM (or SRAM with D-flops) chips. The Arduino board acts as the rest of the computer in this setup. If you wanted to create a video game console, for example, the Nano would handle all the game’s logic. It would then tell the TMS9918 what graphics to display on the screen. The Nano controls the TMS9918 video the RAM chips, where it writes bytes that describe the onscreen content.

    The way the TMS9918 handles graphics is what makes this experiment fun, as it provides a lot of insight into how video game and software developers of the late ’70s and early ’80s worked with limited resources. For instance, the best performance is achievable by displaying text instead of sprites or controlling individual pixels. So some video games would use text characters for their graphics, like an ampersand to represent an enemy.

    Each text character is a hardcoded 8×8 pixel block. The TMS9918 allowed for custom foreground and background colors for characters, but only on a per-row basis. Developers of the era used those hardware limitations in creative ways that resulted in graphics that aren’t even identifiable as being text characters. Sprites are also possible in other modes and you can try it all for yourself by following the tutorial.

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  • Emulate the legendary Altair 8800 on your Arduino Mega

    Emulate the legendary Altair 8800 on your Arduino Mega

    Reading Time: 2 minutes

    Arduino Team — August 25th, 2021

    The Altair 8800 is one of the most important machines in computer history and many consider it to be the first personal computer. But not many computer users today would recognize it as such. At release, it couldn’t even output video and users could only interact with the Altair 8800 through a terminal or the front panel. Now you can relive history by emulating an Altair 8800, complete with front panel, on your Arduino Mega.

    The front panel on the Altair 8800 contained several status lights and toggle switches. Those are cryptic when compared to our modern graphical interfaces, but the Altair 8800’s front panel was integral for working with the machine. Users would load programs and even key in bootloaders using the front panel. The panel would also give you useful debugging information, such as if data was moving from one memory address to another. Interacting with that front panel is a necessity if you want to get the full Altair 8800 experience.

    This Instructables tutorial explains how you can do that using just an Arduino Mega and your computer — no other hardware is necessary. After flashing the provided code, the emulator will boot into MITS Altair 4k BASIC, which was Microsoft’s first software and was coded by Bill Gates himself (along with two other programmers). You can communicate with the emulator through the Arduino serial monitor, similar to how a ’70s computer user would have used a terminal. The serial monitor will also display an ASCII representation of the Altair 8800’s front panel that reacts to your actions and programs.

    If you’ve ever wanted to experience the Altair 8800 for yourself, this is a great way to do so.

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    Website: LINK