The GameTank Is The Latest And Greatest 8-bit Game Console

August 2, 2022 by Robin Kearey 15 Comments

The NES, Atari 2600, the Apple II, the Commodore 64 and the TurboGrafx-16 are just some of the many game consoles and home computers built around the 6502 CPU. And while the 6502 has been pretty much obsolete since the mid-’90s, that hasn’t stopped hackers from building new systems with it in the 21st century. Today we can even show you an entirely new 6502-based game console: the GameTank, designed and built by [Clyde Shaffer].

The GameTank was designed to be easy to build by anyone, and is therefore largely constructed from DIP chips that can be bought new at any component distributor. The main CPU is a WD65C02 running at 3.5 MHz, assisted by a 6522 I/O controller and 32 kB of RAM. Composite video is generated by a clever circuit made out of discrete logic chips. The video card comes with DMA for fast transfers and even includes a blitter, which enables it to move images around the screen quickly without loading the CPU.

For the controllers, [Clyde] decided to go for the more-or-less industry standard DE-9 connector gamepads as used on the Sega Genesis and various Atari consoles. He also made his own controller, a 3D printed one with four directional buttons, three action buttons and a start button. The buttons are implemented with Cherry MX Clear switches — an unusual choice for a gamepad perhaps, but they’re apparently very comfortable for long gaming sessions.

The console itself is also housed in a printed enclosure with a design reminiscent of the Nintendo 64. Game cartridges are inserted at the top and contain an EEPROM chip that can be written with a special programmer. The cartridge port also brings out several internal signals and can therefore be used as an expansion port, similar to the way Super NES cartridges could accommodate enhancement chips.

Games currently available include Tetris, the office-themed platformer Cubicle Knight, a Zelda-style adventure named Accursed Fiend, and a remake of the classic viral animation Bad Apple. [Clyde] provides a comprehensive stack of tools and example code and invites anyone interested to help develop more software for the platform. There’s also a hardware-accurate emulator, which is not only useful if you’re writing new code for the system but also if you simply want to try out the existing games in your browser.

Rolling your own 6502 system is great fun, and we’ve seen several examples over the years: some are built with huge bundles of wire, some are come with a clever programming language, some are so tiny they fit on your wrist, and some are simply beautifully made.

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PERSEUS-9, The Dual-6502 Portable Machine That Should Have Been

July 29, 2022 by Dan Maloney 53 Comments

A question: does anyone who was around in the early days of the 8-bit computer revolution remember a dual-CPU 6502 portable machine like this one? Or just a dual-CPU machine? Or even just a reasonably portable computer? We don’t, but that begs a further question: if [Mitsuru Yamada] can build such a machine today with parts that were available in the era, why weren’t these a thing back then?

We’re not sure we have an answer to that question, but it just may be that nobody thought of it. Or, if they did, the idea of putting two expensive CPUs into a single machine was perhaps too exorbitant to take seriously. Regardless, the homemade mobile is another in a growing line of beautifully crafted machines in the PERSEUS line, all of which have a wonderfully similar look and feel.

For the PERSEUS-9, [Yamada-san] chose a weatherproof aluminum enclosure with just the right form-factor for a mobile computer, as well as a sturdy industrial look. Under the hood, there are two gorgeous wire-wrap boards, one of which is home to the 48-key keyboard and the 40×7 alphanumeric LED matrix display, while the other is a densely packed work of art holding the two 6502s and a host of other DIPs.

The machine is a combination of his PERSEUS-8 computer, his 6802 serial terminal, and the CI-2 floating point interpreter he built for the PERSEUS-8. A brief video of the assembly of this delightful machine is below. One of the many things about these builds that impress us is the precision with which the case is machined, apparently all by hand. How he managed to drill out all those holes for the keyboard without having one even slightly out of alignment without the aid of CNC is beyond us.

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Hackaday Prize 2022: The Baffatari 2600 Adds Atari Compatibility To Retrocomputers

June 29, 2022 by Robin Kearey 16 Comments

Like today’s Intel-AMD duopoly, the market for home computer CPUs in the 1970s and ’80s was dominated by two players: Zilog with their Z80, and MOS Technology with their 6502 processor. But unlike today, even if two computers had the same CPU, it didn’t mean the two were software compatible: differences in memory layout, video interfaces, and storage media meant that software developed for an Atari 2600 wouldn’t run on an Apple I, despite the two sharing the same basic CPU architecture.

[Augusto Baffa]’s latest modern retrocomputer design, the Baffatari 2600, cleverly demonstrates that the difference between those two computers really is only skin-deep. The Baffatari is a plug-in board that adds Atari 2600 functionality to [Augusto]’s earlier Baffa-6502 system, which was designed to be Apple I-compatible. Since both the Apple and the Atari are powered by 6502 CPUs, only a few peripherals need to be swapped to change one into the other.

Sitting on the Baffatari board are two chips essential to the Atari 2600’s architecture: the 6532 RAM I/O Timer (RIOT) that contains the RAM and joystick interface, and the Television Interface Adapter (TIA) that handles the graphics and audio. These chips connect to the Baffa-6502’s system bus, enabling the main CPU to communicate with them and run Atari 2600 software titles. In the video embedded below, you can see several classic games running on the Baffa system.

The basic idea is similar to this RC2014 plug-in board that enables a Z80-based retrocomputer to run MSX and Colecovision titles. In fact, [Augusto] also built such a board for his earlier Z80 project.

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A purple PCB with many DIP chips including a 6502

Hackaday Prize 2022: Reuse Those DIP Chips To Make A 1980s-Style Single-Board Computer

May 28, 2022 by Robin Kearey 30 Comments

With the Great Chip Shortage still delaying deliveries of new components, now might be a good time to look around your lab and inspect those piles of chips that you thought “might come in handy one day”. Chances are you’ll find a good stack of 74xx series logic, once ubiquitous but today mostly obsolete thanks to powerful microcontrollers and FPGAs. It would be a shame to let them go to waste, so why not use them to make a neat 1980s-style computer?

With this idea in mind, [Anders Nielsen] designed the ABN6502: a single-board computer based on the venerable 6502 processor, but with relatively modern interfaces like a VGA monitor output, a PS/2 keyboard connector and even a wireless module to simplify firmware uploads from a PC. One design requirement was to minimize the number of new components needed; the average hacker interested in building the ABN6502 will probably have many of the chips lying around somewhere in their workshop.

The component list reads like a typical bill of materials for a 6502-based computer, but comes with a lot of flexibility to allow for part subsititution. For the CPU, both the classic NMOS 6502 as well as the modern CMOS-based 65C02 are supported, along with their 6522 companion chip that provides I/O ports and timers. A ROM socket can hold either modern, fast flash chips or traditional but slow UV-erasable EPROMs.

Instead of using DRAM chips with their complicated refresh requirements, [Anders] went for 32 KB of SRAM to implement the main memory; unaffordable in the ’80s but easily available today. Standard 74xx series logic chips glue all the components together, again with several options to add or remove features as the user prefers. Pin headers bring out the I/O ports for easy connection to external peripherals.

The ABN6502’s software library is currently limited to a bootloader, but a complete development toolchain based on the CC65 compiler should make it easy to develop all kinds of programs on this platform. We’ve already featured the clever wireless ROM flashing system, as well as a demonstration of the 6502 driving RGB LEDs.

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The Thin-Film Flexible 6502

May 21, 2022 by Jenny List 13 Comments

While our attention is mostly directed towards ever smaller-integrated silicon circuits providing faster and faster computing, there’s another area of integrated electronics that operates at a much lower speed which we should be following. Thin-film flexible circuitry will provide novel ways to place electronics where a bulky or expensive circuit board with traditional components might be too expensive or inappropriate, and Wikichip is here to remind us of a Leuven university team who’ve created what is claimed to be the fastest thin-film flexible microprocessor yet. Some of you might find it familiar, it’s our old friend the 6502.

The choice of an archaic 8-bit processor might seem a strange one, but we can see the publicity advantage — after all, you’re reading about it here because of it being a 6502. Plus there’s the advantage of it being a relatively simple and well-understood architecture. It’s no match for the MHz clock speeds of the original with an upper limit of 71.4 kHz, but performance is not the most significant feature of flexible electronics. The production technology isn’t quite ready for the mainstream so we’re unlikely to be featuring flexible Commodore 64s any time soon, but the achievement is the impressive feat of a working thin-film flexible microprocessor.

Meanwhile, if you’re curious about the 6502, we took a look at the life of its designer, [Chuck Peddle].

Glow In The Dark Computer Memory Illuminates The Fundamentals

April 11, 2022 by Chris Wilkinson 22 Comments

Computer memory has taken on many forms over the years, from mercury-based delay-line tubes to handwoven magnetic core. These days, volatile storage using semiconductors has become ubiquitous with computing, but what if there was a better way? [Michael Kohn] has been working on a new standard for computer memory that uses glow in the dark stickers.

Clearly we jest, however we’re still mighty impressed by the demonstration. Eight delightful star-shaped phosphorescent stickers represent eight bits of memory, totaling one byte. The glow in the dark material is stuck to the inside of short cylinders, each of which contains a white LED and a phototransistor. The memory array is wired up to an iceFUN FPGA board, which is then connected via level shifters to a Western Design Center MENSCH single board computer.

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An NRF24L01 module soldered onto a 6502 single-board computer

Wireless Bootloader Saves You From Swapping ROM Chips

April 5, 2022 by Robin Kearey 14 Comments

Flashing your code into an Arduino, an ESP32 or any other modern microcontroller platform is pretty straightforward: connect the device through USB, fire up the appropriate software platform, and press “program”. But those who followed embedded programming classes in the ’80s and ’90s will remember a more complicated procedure that consists of swapping EPROM chips between a programmer, a target board and a UV eraser. Veterans of that era might even remember how you could overwrite a previous program with NOPs and place new code behind it, to save yourself a trip to the “blank chips” bin.

If you’re a retrocomputer enthusiast and would like to have the easy programming of modern tools, but the authenticity of a self-contained ROM-loading computer, you might want to check out [Anders Nielsen]’s latest design of a wireless boot loader for a 6502 single board computer. The target platform for this project is a beautiful custom-made 6502-based retrocomputer that [Anders] documented in detail on his Hackaday.io page.

The basic idea here is to have a wireless receiver on the target system that receives data from a transmitter connected to a modern PC. When you click “program”, the object code is sent to the 6502 machine, stored in RAM and executed. The wireless link is implemented with a pair of nRF24L01 2.4 GHz modules that communicate through SPI. Since [Anders]’s Mac Mini doesn’t come with GPIO ports he hooked up the transmitter to a Raspberry Pi which he controlled through a network link.

On the 6502 side he wrote a bootloader in assembly language, which bit-bangs the SPI protocol to communicate with the wireless module. A simple user interface is included to allow the user to control the loading and running of programs. All code and hardware documentation is available on Github for use by anyone with a similar 6502 system.

Those nRF24L01s are versatile little things: we’ve seen them being used to transfer anything from MIDI data to TCP/IP links, as well as code for other microcontroller platforms.

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