Hacklet 119 – Retrogaming Console Hacks

If you haven’t heard, retrogaming is a thing. 40-somethings are playing the games of their youth alongside millennials who are just discovering these classic games. There are even folks developing new homebrew games for consoles as far back as the Nintendo Entertainment System and the Atari 2600. This week on the Hacklet, we’re highlighting some of the best retrogaming console hardware hacks on Hackaday.io. Note that I did say hardware hacks. The focus this week is on games played on the original hardware. Don’t worry though, I’ll give emulated projects some love in a future Hacklet.

bankerWe start with [danjovic] and Atari 2600 Bankswitch Cartridge. The Atari 2600 is a legendary system. Millions of hackers’ first exposure to gaming came through its one button joystick. To make the unit affordable, Atari used a MOS Technology 6507 processor. Essentially it’s a 6502 in a 28-pin package. This meant several features got nerfed, most notably the address space. The 6507 can only address 8KB of RAM. In the Atari, only 4KB is available to the cartridge. Games got around the 4KB limit by bank switching – write a value to a magic address, and the bank switching logic would swap in a whole different section of cartridge ROM. There were several different bank switching schemes used over the years. [Danjovic] has created his own version of this bank switching logic, using only classic 74 series logic chips.


nesmodNext up is [ThunderSqueak] with Top Loader NES composite mod. Toward the end of the NES’s life, Nintendo introduced a cost-reduced version known as the “top loader”. This version had a top loading cartridge and no DRM lock-out chip. Unfortunately it also did away with composite AV ports. The only way to hook this NES to your TV was through the RF modulated output. [ThunderSqueak] and a number of other intrepid hackers have fixed this problem. All it takes is a 2N3906 PNP transistor and a few jellybean parts. The video and audio outputs are pulled from the motherboard before they enter the RF modulator. One nice feature is the clean connectors. [ThunderSqueak] used connectors from modular in-wall AV boxes for a setup that looks as good as it works.

segaNext we have [makestuff] with USB MegaDrive DevKit. Sega’s MegaDrive, or Genesis as it was known here in the USA, was a groundbreaking console. It used a Motorola 68000 16-bit CPU while most other systems were still running a Z80 or a 6502. People loved this console, and there are plenty who still want to develop software for it. Enter [makestuff] with his development kit. On a card with a $40 USD bill of materials, he’s managed to fit SDRAM, an FPGA, and a USB interface. This is everything you need to load and debug software on an unmodified console. The FPGA had enough logic left over that [makestuff] was able to implement a continuous bus cycle tracer over USB. Nice work!

robbbFinally, we have our own [Joshua Vasquez] with R.O.B. 2.0. The original NES came in a deluxe version with a special pack in – a robot. Robotic Operating Buddy, or ROB for short, would play games with the player. Unfortunately ROB was a bit of a flop. It only worked with two games, Gyromite and Stack-Up Ice Climber. Most ROB units eventually found their way to the recycling bin. [Joshua] is building a new version of the ROB, with modern controls. He’s already modeled and 3D printed ROB’s head. I can’t wait to see this project come together!

If you want to see more retrogaming goodness, check out our new retrogaming hardware hacks list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

3 Billion Devices And A Sega Genesis Run Java

A few years ago, [Mike]’s friend gave him an old Sega Genesis with the very cool and somewhat rare SegaCD drive attached. The SegaCD gave him an idea – while it’s not easy to burn a cartridge and play homebrew games on a real Genesis console, everyone has a CD burner somewhere. [Mike] began writing his demo and then realized adding Java would be easy on the 68000. The result is Java on three billion devices and a Sega Genesis.

This project is built around Java Grinder a Java byte code compiler that will compile classes, factories, and all the horrible Java design.design.pattern.pattern.patterns() into assembly language. Already, there are a lot of platforms supported by Java Grinder, including the Commodore 64, the TI99, and thanks to some work from [Joe Davisson], the Apple IIgs

With a byte code compiler, an assembler, and an API for the Sega-specific hardware, [Mike] set about building his demo. Since this was a Sega, it needed the ‘SEGA’ sound at the start. [Mike] ended up recording his voice saying ‘JAVA!’ This plays through the Z80 on the Genesis.

The complete demo – viewable in its emulated format below – has everything you would expect from a proper demo. Starfields, dancing sprites, and even a Mandelbrot pattern make it into the three-minute long demo.

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Winning the Console Wars – An In-Depth Architectural Study

From time to time, we at Hackaday like to publish a few engineering war stories – the tales of bravery and intrigue in getting a product to market, getting a product cancelled, and why one technology won out over another. Today’s war story is from the most brutal and savage conflicts of our time, the console wars.

The thing most people don’t realize about the console wars is that it was never really about the consoles at all. While the war was divided along the Genesis / Mega Drive and the Super Nintendo fronts, the battles were between games. Mortal Kombat was a bloody battle, but in the end, Sega won that one. The 3D graphics campaign was hard, and the Starfox offensive would be compared to the Desert Fox’s success at the Kasserine Pass. In either case, only Sega’s 32X and the British 7th Armoured Division entering Tunis would bring hostilities to an end.

In any event, these pitched battles are consigned to be interpreted and reinterpreted by historians evermore. I can only offer my war story of the console wars, and that means a deconstruction of the hardware.

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It’s a Sega It’s a Nintendo! It’s… Unique!

Before the days of the RetroPie project, video game clones were all the rage. Early video game systems were relatively easy to duplicate and, as a result, many third-party consoles that could play official games were fairly common. [19RSN007] was recently handed one of these clones, and he took some pretty great strides to get this device working again.

The device in question looks like a Sega Genesis, at least until you look closely. The cartridge slot isn’t quite right and the buttons are also a little bit amiss. It turns out this is a Famicom (NES) clone that just looks like a Sega… and it’s in a terrible state. After a little bit of cleaning, the device still wasn’t producing any good video, and a closer inspection revealed that the NOAC (NES-on-a-Chip) wasn’t working.

Luckily, [19RSN007] had a spare chip and was able to swap it out. The fun didn’t stop there though, as he had to go about reverse-engineering this chip pin-by-pin until he got everything sorted out. His work has paid off though, and now he has a video game system that will thoroughly confuse anyone who happens to glance at it. He’s done a few other clone repairs as well which are worth checking out, and if you need to make your own NES cartridges as well, we’ve got you covered there, too.

Fixing Sega Cartridges With Old BIOS Chips

For one reason or another, [Dragao] has an old Sonic The Hedgehog cartridge that throws an illegal instruction somewhere in the Marble Zone stage. While the cause of this illegal instruction is probably cosmic rays, how to repair this cartridge isn’t quite as clear. It can be done, though, using BIOS chips from an old computer.

[Dragao] got the idea of repairing this cartridge from Game Boy flash carts. These cartridges use chips that are a simple parallel interface to the address and data lines of the Game Boy’s CPU, and Sega Genesis / Mega Drive flash cart would work the same way. The problem was finding old DIP flash chips that would work. He eventually found some 8-bit wide chips on the motherboard of an old computer, and by stacking the chips, he had a 16-bit wide Flash chip.

To program the chips, [Dragao] wired everything up to an Arduino Mega, put a ROM on the chip, and wired it up to the old Sega cartridge. Surprisingly or unsurprisingly, everything worked, and now [Dragao] has a fully functioning copy of Sonic The Hedgehog.

Genezap improves your video game skills using corporal punishment


As if getting your ass handed to you while playing video games wasn’t annoying enough, [furrtek] decided that the best way to help improve his skills was by inflicting physical pain each time his on-screen character died.

While perusing the Internet looking for something to break through the doldrums of the day, he came upon a video in which someone decided to try on a dog shock collar just for kicks. This sparked [furrtek’s] imagination, and he started to think that it would be pretty cool to use the same sort of device to make dying in a video game that much more unpleasant.

After ordering a set of collars online, he tore them apart to see how they functioned, and to measure just how big of a jolt they were able to deliver. [furrtek] then modified two Genesis controllers with a pair of ATtiny 25s, which let him send the fire signal to the collars. Unfortunately, stock Genesis games don’t allow you to send signals to the controllers, so [furrtek] had to spend some time hacking ROM images to trigger events when players are injured or lose a life.

We think the project is pretty slick, and if you don’t mind fiddling with your old controllers, you too can have a merciless trainer strapped around your neck. For those slightly more averse to pain, you can watch [furrtek] and his friend [Dyak] suffer the consequences of poor gameplay for your amusement.

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Reading Sega carts off a breadboard

Golden Axe is great, and the Sonic 3/Sonic and Knuckles combo is one of the highest works of art from the 16-bit era, but for those of us without a working Genesis or Megadrive, we’ve had to make due with the ROMs others provide. [Lee] figured out an easy way to read the data off these old Sega cartridges using easily scavenged parts and an Arduino Mega, paving the way for an Arduino-based ROM dumper.

The connector on the bottom of a Sega Genesis cartridge has a 2×32 pinout, normally requiring 64 connections to actually read the card. These connectors aren’t readily available, but [Lee] did manage to find a few 2×31 pin connectors lying around in the form of old ISA sockets. The outer pins of a Genesis cart are used for grounds and a ‘cartridge insert’ slot, and after filing away the end of an old ISA connector, [Lee] found he could actually read the data on these old game cartridges.

There are 49 data and address pins on these old Sega carts, so an Arduino Mega needed to be brought into the mix to actually read some of the data on the ROM chip. As of now, [Lee] can read data from the cart but has only gotten so far as to read the licensing data stored at 0x80. Still, very cool and the first step towards an Arduinofied Sega cart dumper.