PicoROM, A DIP-32 8-Bit ROM Emulator

November 5, 2024 by Dave Rowntree 13 Comments

As we all know, when developing software for any platform or simply hacking a bit of code to probe how something works, the ability to deploy code rapidly is a huge help. [Martin Donlon], aka [wickerwaka], is well known in retro gaming and arcade hardware reverse engineering circles and had the usual issues figuring out how an arcade CPU board worked while developing a MiSTer core. Some interesting ASICs needed quite a bit of poking, and changing the contents of socketed ERPOMs is a labour-intensive process. The solution was PicoROM, a nicely designed ROM emulator in a handy DIP-32 form factor.

As the title suggests, PicoROM is based on the Raspberry Pi RP2040. It emulates an 8-bit ROM up to 2MBits in size with speeds up to 100ns. Since it uses the RP2040, USB connectivity is simple, enabling rapid uploading of new images to one (or more) PicoROMs in mere seconds. A vertically orientated USB-C connector allows multiple PicoROMs to be cabled to the host without interfering with neighbouring hardware. The firmware running on core 1 passes data from the internal 264K SRAM, using the PIO block as a bus interface to the target. A neat firmware feature is the addition of a mechanism to use a ROM region as a bidirectional control channel, which the software running on the target can use to communicate back to the host computer. This allows remote triggering of actions and the reporting of responses. Responses which may not be physically observable externally. [Martin] is using this feature extensively to help probe the functionality of some special function chips on the target boards, which is still a slow process but helped massively by reducing that critical software iteration time. The PCB was designed with KiCAD. The project files for which can be found here.

This isn’t the first time we’ve seen the RP2040 used for ROM emulation; here’s a pile of wires that does the same job. It just isn’t as pretty. Of course, if you really must use EPROMs, then you could give this sweet programmer a look over.

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Atari’s Pac-Man Flop: How A Classic Went Off-Course

October 25, 2024 by Heidi Ulrich 35 Comments

For fans of retro games, Pac-Man is nothing short of iconic—a game so loved it’s been ported to nearly every console imaginable. But the Atari 2600 version, released in 1982, left players scratching their heads – as laid out in a video by [Almost Something]. Atari had licensed Pac-Man to ride the wave of its arcade success, but the home version, programmed solely by [Todd Fry], missed the mark, turning an arcade icon into a surprising lesson in over-ambitious marketing.

Despite the hype, [Fry] faced an almost impossible task: translating Pac-Man’s detailed graphics and complex gameplay to the Atari’s limited 4 K cartridge with only 128 bytes of RAM. Atari’s strict limitations on black backgrounds and its choice to cut costs by sticking with a 4 K cartridge left the game barely recognizable. The famous pellet-chomping maze became simpler, colors were changed, and the iconic ghosts—reduced to single colors—flickered constantly. And then, Atari went all in, producing twelve million copies, betting on the success of universal appeal. In a twist, Pac-Man did sell in record numbers (over seven million copies) but still fell short of Atari’s expectations, leaving millions of unsold cartridges eventually dumped in a New Mexico landfill.

This debacle even kind of marked Atari’s 1983 decline. Still, Pac-Man survived the hiccup, evolving and outlasting its flawed adaptation on the 2600. If you’re interested in learning more about the ins and outs of game ports, check out the fantastic talk [Bob Hickman] gave during Supercon 2023.

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Asteroids: Kessler Syndrome Edition

August 5, 2024 by Bryan Cockfield 6 Comments

Asteroids, the late-70s arcade hit, was an immensely popular game. Often those with the simplest premise, while maintaining a fun, lighthearted gameplay have the most cultural impact and longest legacy. But, although it was popular, it doesn’t really meet the high bar of scientific fidelity that some gamers are looking for. That’s why [Attoparsec] built the Kessler Syndrome Edition of this classic arcade game.

The Kessler Syndrome is a condition where so much man-made debris piles up in low-Earth orbit that nothing can occupy this orbit without getting damaged or destroyed by the debris, and thus turning into more debris itself in a terrible positive feedback loop. [Attoparsec] brings this idea to Asteroids by reprogramming the game so that asteroids can be shot into smaller and smaller pieces but which never disappear, quickly turning the game into a runaway Kessler Syndrome where the chance of survival is extremely limited, and even a destroyed player’s ship turns into space junk as well.

To further the scientific accuracy and improve playability, though, he’s added a repulsor beam mechanism which can push the debris a bit and prolong the player’s life, and also added mass effect reactions so that even shooting bullets repels the player’s ship a bit. The build doesn’t stop with software, either. He also built a custom 70s-style arcade cabinet from the ground to host the game.

Asteroids is still a popular platform for unique builds like this. Take a look at a light-vector game using lasers to create the graphics, or this tiny version of the game that uses a real CRT.

Thanks to [smellsofbikes] for the tip!

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Building The Unreleased Lemmings Arcade Cabinet From 1991

July 29, 2024 by Maya Posch 7 Comments

Back in the early 90s the world was almost graced with an arcade version of Lemmings, but after a few board revisions it was abandoned in 1991. Now the folk over at UK-based [RMC – The Cave] on YouTube have managed to not only get their mitts on a nearly finished prototype board, but have also designed and built a period-appropriate cabinet to go with it. This involved looking at a range of arcade cabinets created by Data East and picking a design that would allow both for the two-player mode of the game, and fit the overall style.

Arcade cabinets came in a wide range of cabinet styles and control layouts, largely defined by the game’s requirements, but sometimes with flourishes to distinguish the cabinet from the hundred others in the same arcade.

In this particular case the typical zig-zag (Z-back) style was found to be a good fit as on the Data East Night Slashers 1993-era cabinet, which then mostly left the controls (with two trackballs) and cabinet art to figure out. Fortunately there is plenty of inspiration when it comes to Lemmings art, leading to the finished cabinet with the original mainboard, the JAMMA wiring harness with MultiPi JAMMA controller, a 19″ CRT monitor and other components including the 3D printed controls panel.

With more and more new arcades popping up in the US and elsewhere, perhaps we’ll see these Lemmings arcade cabinets appear there too, especially since the ROMs on the prototype board were dumped for convenient MAME-ing.

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Portable, Full-Size Arcade Cabinets

June 27, 2024 by Bryan Cockfield 3 Comments

Believe it or not, there was a time when the only way for many of us to play video games was to grab a roll of quarters and head to the mall. Even though there’s a working computer or video game console in essentially every house now doesn’t mean we don’t look back with a certain nostalgia on those times, though. Some have turned to restoring vintage arcade cabinets and others build their own. This hackerspace got a unique request for a full-sized arcade cabinet that was also easily portable as well.

The original request was for a portable arcade cabinet, and the original designs were for a laptop-like tabletop arcade. But further back-and-forth made it clear they wanted full-size cabinets that just happened to also be portable. So with that criteria in mind the group started building the units. The updated design is modular, allowing the controls, monitor, and Raspberry Pi running the machines to be in self-contained units, with the cabinets in two parts that can quickly be assembled on-site. The base is separate and optional, with the top section capable of being assembled on the base or on something like a tabletop or bar, and the electronics section quickly drops in.

While the idea of a Pi-powered arcade cabinet is certainly nothing new, the quick build, prototyping, design, and final product that’s mobile and quickly assembled are all worth checking out. There is even more information on the build at the project’s GitHub page including Fusion 360 models. If you need your cabinets to be even more portable, this tabletop MAME cabinet is a great place to start.

Computer Space Replica Is Up And Running

October 2, 2023 by Richard Baguley 8 Comments

You never forget your first time — watching someone pour several quid’s worth of 10p pieces into a Space Invader machine in 1978, upsetting for a youngster who wanted to have a turn. We’re still waiting, but [Alston] has found an interesting way to get around those arcade video game hoggers by building a replica of Computer Space, the first commercial arcade video game.

Released in 1971, the groundbreaking game was designed by gaming legends [Nolan Bushnell] and [Ted Dabney], and came in a striking curvy fiberglass case that was molded by a manufacturer of swimming pools. [Alston] hasn’t built the case yet, but he does have the electronics up and running.

The electronics of Computer Space are interesting, because there is no microprocessor in there. Instead, it is built from discrete components. [Nolan] had originally planned to use a mini computer called the Data General Nova 800. However, he realized that he could make it cheaper by building it out of discrete components. As [Nolan] described it in an oral history at the Smithsonian [PDF link], the idea came to him after a post-Thanksgiving dinner nap:

“Screw the minicomputer. Get rid of it. Do it all in hardware. Make the game out of this collection, just make it a simple state machine. And the minute that happened, it was like knife through butter. Not only did I get the cost down, but what was budgeted for $1,500 worth of minicomputer, the whole damn computer cost me less than $300 in glue parts. So, I knew that I had something.”

That decision makes it an interesting project to build a replica. Although you can emulate it on a modern computer easily (there is even a version that runs in CSS in the browser). [Alston] is going the hard route, building replica PCBs and using the same components where possible, helped by people who have documented it. So far, the boards are and running and displaying a grainy, pixelated image on a portable TV.

The next step is to take the replica electronics box he has built and make a cabinet to put it into. That’s a big project, and [Alston] is looking for someone with an original cabinet that he can examine and document.

Showing the end result - a Defender machine copy in all its glory, with a colourful front panel with joysticks.

Defender Arcade Rebuilt To Settle A Childhood Memory

March 3, 2023 by Arya Voronova 7 Comments

[Jason Winfield] had a nemesis: the Defender arcade machine. Having put quite a number of coins into one during his childhood, he’s since found himself as a seasoned maker, and decided to hold a rematch on his own terms. For this, he’s recreated the machine from scratch, building it around the guts of a Dell laptop, and he tells us the story what it took to build a new Defender in this day and age.

Defender was a peculiar machine — it was in cocktail table format, unlike many other arcade machines of that period. From pictures, he’s redesigned the whole thing in Fusion 360, in a way more desk-friendly format, but just as fancy looking as before.

As for the laptop, gutting it for its mainboard, screen, and speakers was a surprisingly painless procedure — everything booted up first try. A few board-fitted brackets and a swap from a HDD to a USB flashdrive for the OS later, the electronics were ready. As he was redesigning the entire arcade machine anyway, the new design control panel was also trimmed down for ease of use, while preserving the original colorful look.

All in all, an impressive build from [Jason]. After all was set and done, we don’t doubt that he went on to, let’s say, settle some old scores. It’s not the first time we see a desktop-sized arcade cabinet, and you gotta admire the skills making such a machine smaller while sticking to the old-timey aesthetic! Or, perhaps, would you like a cabinet that’s more subtle?

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