We’ve seen our share of homebrew computers over the years. Usually, these bare-bone systems use a small, early 80s-era microprocessor such as the Z80 or 6502. These little 8-bit machines are awesome, but somewhat limited in their capability. [BigDumbDinosaur] sent in a computer he’s been working on for a few years now featuring the infamous 65816 CPU – the same CPU found in the Apple IIgs, the Super Nintendo, and [Jeri Ellsworth]’s C-ONE computer.

The 65816 is a direct descendant of the venerable 6502 CPU found in the Commodore 64, Apple II, and just about every 80s microcomputer of note. [BigDumbDinosaur] chose the 65816 for its backwards-compatibility with the fun to program 6502 and the ability to use high clock rates and tons of address space for a very cool design.

After a ton of careful design and consideration, [BigDumbDinosaur]’s computer included a real-time clock, a watchdog timer, a serial port, 256kB of ROM, and 128kB of RAM.

It’s a really wonderful build, but [BigDumbDinosaur] isn’t done with this project yet. He’s working on version 2 of a 65816 computer that will use programmable ‘glue’ logic, a lot more RAM, have a SCSI interface (for a hard drive), and have preemptive multitasking.

An awesome job, and it’s wonderful to see the wonderful 65816 make its way into another homebrew computer. Now if only we could find a 68000-based homebrew computer…

The 6502 CPU is probably the most famous of all the 8-bit processors out there, whether in the form of bare chips for homebrew computers, or as slightly modified derivative chips found in everything from the C64, the NES, and the BBC Micro. For this edition of the Hacklet, we’re taking a look at all the 6502-based builds on hackaday.io.

There aren’t many transistors on a 6502, making it perfect for implementing on an FPGA. [Michael A. Morris] has an Arduino FPGA shield, and his soft-6502 project is called Cameleon. There’s a bunch of SPI Flash and FRAM on board, and the 128kB of (parallel) SRAM on the board is more than enough to handle any computational task you can throw at it.

Since the Cameleon is built on programmable logic, [Michael] thought it would be a good idea to put some of those unused opcodes to use. There are instructions for coprocessor support, and a bunch of instructions specifically designed to make the Forth implementation easier.

Maybe programmable logic isn’t your thing, and you’d just like a simple computer like the Ohio Scientific or the Apple I. The L-Star is for you. That’s [Jac Goudsmit]’s build featuring a 6502, a Parallax Propeller, and little else.

The Parallax Propeller is a powerful (multi-core!) chip that’s easily capable of handling video out, keyboard in, and serving up the ROM and RAM of a computer. [Jac]’s build does it all beautifully, and if you’re looking for the easiest way to run code on a 6502, this is how you do it.

6502s were found in just about everything, and while poking around at the local e-waste recycler, he stumbled upon something rather interesting. The case badges screamed, “BS medical device”, but after poking around a bit, he figured out this was an MTU-130 system, a machine that was apparently the top of the line in its day.

There’s some weird stuff going on in this machine – 18-bit addressing and 80kB of RAM. So far [Eric] has managed to dump the ROM, and he’s taking a look at the floppy controller board to see if he can figure out how it’s mapped. It’s one thing to figure out what’s broken on an Apple II or C64; those are well documented machines. It’s another thing entirely to figure out a machine very few people have heard of, and we tip our hat to [Eric] and his efforts.

Here’s a build that both does and doesn’t have a 6502 in it. [BladeRunner]’s SheMachine is a single board computer that has a 65c816 in it. The ‘816 is an interesting beast that operates as a standard 6502 until a bit is flipped in one of its registers. After that, it has a 24-bit address space for addressing 16 Megabytes of memory, 16-bit registers, but is still completely backwards compatible with the 6502. Yes, it does have weird interleaved address pins, but we can only imagine what the world would be like if this chip came out a few years earlier…

[BladeRunner] is designing the SheMachine with 1MB of SRAM – more than enough, really – and is mapping all the memory through a CPLD. That’s how you should do it, anyway.

The 6502 is a classic piece of computing history. Versions of this CPU were found in everything from the Apple ][, to the Nintendo Entertainment System, and the Commodore 64. The history of the 6502 doesn’t end with video games; for the last forty years, this CPU has found its way into industrial equipment, medical devices, and everything else that doesn’t need to be redesigned every two years. Combine the longevity of the 6502 with the fact an entire generation of developers first cut their teeth on 6502 assembly, and you have the makings of a classic microprocessor that will, I’m sure, still be relevant in another forty years.

The cathedral of The 6502 is Western Design Center. For more than 35 years, WDC has been the home of 6502-related designs. Recently, WDC has been interested in the educational aspects of the 6502, with one of the VPs, [David Cramer], lending his time to an after-school club teaching opcodes.

The folks at WDC recently contacted me to see if I would give their hardware a close look, and after providing a few boards, this hardware proved to be both excellent. They’re great for educators adventurous enough to deviate from the Arduino, Processing, and Fritzing zeitgeist, and for anyone who wants to dip their toes into the world of 65xx development.

The Single Board Computers

WDC sent me the W65C02SXB and the W65c816SXB, two single board computers based on the 65C02 and the 65C816, respectively.

There are hundreds of very well-documented designs floating around the Internet for 65xx-based computers, but most of these designs have a lot in common. If you’re looking to build your own 6502-based computer, you’ll need a CPU, some RAM, and an EEPROM or Flash chip. For peripherals, you’ll be looking at the 6520 PIA, a chip that provides two eight-bit ports of I/O, the 6522 VIA a more advanced I/O chip with timers and a shift register, and maybe an 6551 ACIA communications/serial chip if you’re a purist. This is the standard compliment of chips for a 6502-based computer, and if you believe [Chuck Peddle], the 6502 wasn’t that useful without these support chips.

Both the ’02 and ‘816-based single board computers from WDC feature an ACIA, a PIA, and two VIAs – the second VIA is connected to a microUSB interface designed for WDC’s Terbium IDE (TIDE). More on TIDE in a bit. Each board also has 32kB of SRAM and a 128kB Flash chip mapped into the top 32k of memory. This is a fairly standard layout for just about every homebrew 6502 computer, but there are a few features that make this board special. Every pin you would ever need – data, address, control, and some chip selects – are available on a header running the entire length of the board. This is great if you’d like to interface an SXB with some old hardware, but the potential for creating new hardware is interesting. When I talked to [David Cramer] and [David Gray] at WDC, we speculated on what interesting hardware could be made that supports this gigantic header. The board might be too big and cumbersome for a quadcopter, but a 3D printer controller board is entirely reasonable, and would probably work very well.

The 65C816

The Western Design Center doesn’t just deal with the 6502 and its support chips. It remains the only place where you can get the 65C816, a greatly expanded CPU built on the 6502 ISA.

The ‘816 is a very interesting chip, most famous for its use in the Apple IIgs and the Super Nintendo. With a 24-bit address bus, it supports 16 Megabytes of RAM, has 16-bit registers, and a few new instructions over the 6502. Most impressively, when you first turn a 65C816 on, it starts up in a 6502 emulation mode that is 100% compatible with the 6502 until you flip a bit in a ‘hidden’ register.

With new stack instructions and compatibility with the 65C02, you have to wonder what would have happened if the 65C816 were introduced a few years earlier. The chip was finished in 1984 in time for Apple to use it in the IIgs, and for [Bil Herd] to realize, ‘the reason to use it is because the competition is using it wasn’t going to be a successful pitch.’ A few years earlier, and this chip would have at least been considered in the initial designs of the Apple Lisa, Macintosh, the Atari ST line, and possibly even the IBM PC. It’s the greatest ‘what-ifs’ of computing history.

For the last 30 years, WDC have been the keepers of the 65C816 flame, and of course their educational offerings include a single board computer based around this chip. It is more or less identical to the W65C02SXB with PIA breakouts, VIA breakouts, and an ACIA breakout. The larger set of connectors contains all the data, address, and control lines of the XBus02 connector of the W65C02SXB, save for additional pins for the extra address lines.

Best of all, with a 65C816 development board, there’s no need to deal with the multiplexed data and address lines. Writing ‘816 code is as simple as plugging the board into your computer and mashing the keyboard; the Western Design Center has the only modern ‘816 C compiler, after all.

Terbium IDE

All of the WDC boards work with the Terbium IDE, the IDE packaged with the WDCTool suite. This is the interface for the compiler, linker, the editor of your choice, and a simulator. Truth be told, it’s not exactly a modern IDE – it’s Windows only, and my battle station (Win 8.1) saw the best results running in WinXP Sp2 compatibility mode.

Although TIDE is a little rough around the edges, it’s not really fair to compare this to Visual Studio or Eclipse; these high-end IDEs will always have more features and more polish than an IDE built for a single platform. Also, it’s an IDE, and being rough around the edges is the default, not an exception.

Aside from compiling and linking, TIDE also has another neat feature that’s directly applicable to the SXB boards: a simulator and debugger.

The addition of a simulator and debugger in TIDE is something you’re not going to get if you build your own 6502 single board computer. With the simulator and debugger, you can step into code, set breakpoints, and generally do everything you would expect to be able to do with an embedded IDE.

The sample project for the W65C02SXB was a ‘light up a seven segment display with a VIA’ tutorial, and this demonstrates the potential of the debugger; it even simulates the seven segment display with the help of a little code.

There are a few extra features in TIDE that tie into FPGA-related stuff for WDC’s soft cores for the ’02 and ‘816, but since that’s far beyond the boards I have, those buttons were left alone.

The Microcontroller Development Boards

WDC has not been resting on their laurels for 40 years. Their educational tools also include microcontrollers based on the 65c02 and 65c816. These are the 65C134SXB (based on the ’02, and was originally designed for life support), and the W65C265SXB (based on the 65c816).

Each of these boards feature the W65C134S or W65C256S microcontroller with 32kB of SRAM, a socket for a 32PLLC Flash ROM, one large connector that is more or less the same as their ‘full microprocessor’ counterparts, and three 10-pin connectors that are used for basic I/O, the Serial Interface Bus, and UART signals.

Although these microcontroller development boards appear very minimal – there are only four chips, a hand full of passives, and a bunch of pin headers, after all – appearances are deceiving. The microcontrollers are actually incredible pieces of engineering that really aren’t comparable to anything else on the market.

Inside both of these microcontrollers is a ROM monitor that functions just like any monitor program you’d find in an ancient computer. With this monitor, you can read and write to memory addresses, jump to addresses, and run code. All that’s needed is a USB cable, a terminal emulator (CoolTerm, Putty, a neat little Python script, or anything else that can connect to something over a serial port, 9600, 8N1) [Rod Biresch] has a great tutorial for entering opcodes into the ‘265SXB to blink an LED. Yes, it’s the most basic thing you can do with a microcontroller, but it does work, and can serve as the first stepping stone to more complex applications of an embedded 65xx ISA microcontroller.

Like their bigger brothers, they are also supported by the WDC’s own development environment, TIDE. With this, you can throw assembly or C at these little boards and they’ll chug right along.

Conclusion

There is one fairly large drawback to the single board computers from WDC – the price. The W65C02SXB and W65C816SXB go for a little under $200 USD. The microcontroller variants – the W65C134 and W65C265 knock $100 off the price of their bigger brothers. When you can get an Arduino Nano clone for $2 with free shipping, this looks insane at first glance. After thinking about it, I’m not convinced the price actually is insane.

While you can pull a 6502 out of any old computer, you’re not going to find new chips from anyone but WDC. Being in the 6502 game is a comparatively low-volume business, and for every classic microprocessor, there are thousands of ARM chips.

That being said, if you were to build a 6502 or 65816 single board computer, you’ll also need those VIAs and PIAs; again, not chips you can pick up for a dollar a piece. I’ve built a 6502-based computer, and in terms of cost, my build wasn’t very far off. If you consider the effort that goes into building your own SBC… well, what do you value your time at?

The microcontroller variants of WDC’s boards are by far their most interesting offerings. There’s a common trope in modern 6502 builds that offload nearly everything to a microcontroller, but keep the 6502 in it’s classic 40-pin DIP format. You’ve seen it done with the Propeller, with an ATMega, and with the Propeller again. The 65C134 and ~265 do this job exceptionally well, and they have a built-in monitor to get you typing in machine code fast. That’s the goal of every homebrew computer, really.

For an educational offering, WDC’s single board computers do exactly what they’re designed to do: get people learning assembly and opcodes and machine codes. There’s still a value in this, especially if you’re going to continue hacking on Arduinos and ARMs. The microcontroller boards are a great introduction to some seriously interesting hardware, and I can’t wait to see the retro/homebrew scene dig into some serious tinkering with these machines.

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.

An Architectural Study of the Sega Genesis and Super Nintendo

The traditional comparison between two consoles is usually presented as a series of specs, a bunch of numbers, and tick marks indicating which system wins in each category. While this does illustrate the strengths and weaknesses of each console, it is a rhetorical technique that is grossly imprecise, given the different architectures. The usual benchmark comparison is as follows:

Conventional wisdom – and people arguing on the Internet – tells you that faster is better, and with the Sega console having a higher clock speed it’s capable of doing more calculations per second. Sure, it may not be able to draw as many sprites on the screen as the SNES, but the faster processor is what allowed the Genesis / Mega Drive to have ‘faster’ games – the Sonic series, for example, and the incredible library of sports games. It’s an argument wrapped up in specs so neatly this conventional wisdom has been largely unquestioned for nearly thirty years. Even the Internet’s best console experts fall victim to the trap of comparing specs between different architectures, and it’s complete and utter baloney.

Let’s take a look at one of these numbers – the CPU speed of the SNES and the Genesis/Mega Drive. The SNES CPU, a Ricoh 5A22 is based on the 65C816 core, an oft-forgotten 16-bit offshoot of the 6502 and related chips found in everything from the Apple II, Commodore 64, and even the original Nintendo NES. The 5A22 inside the SNES is clocked at around 2.68 MHz for most games. The Sega used a 68000 CPU clocked at 7.67 MHz. By comparing just these two numbers, the SNES wins, but this isn’t necessarily the truth.

In comparing the clock speed of two different CPUs, we’re merely looking at how frequently the bus is accessed, and not the number of instructions per second.

In the 68000, each instruction requires at least eight clock cycles to complete, whereas the 65C816 – like it’s younger 6502 brother – could execute an instruction every two or three clock cycles. This means the Sega could handle around 900,000 instructions per second, maximum. The SNES could compute around 1.7 Million instructions per second, despite it’s lower clock speed.

Even though the Sega console has a faster clock, it performs fewer instructions per second.

And so we come to the crux of the argument; the statistics of the great console wars, while not wrong, are frequently misinterpreted. How then do we decide an outcome?

The Architecture of the Sega Genesis / Mega Drive

While the Sega Genesis/Mega Drive is usually cited as having a 68000 CPU, this isn’t a complete picture of what’s going on inside the Sega console. In effect, the Genesis is a dual-processor computer with two CPUs dedicated to different tasks. The 68000 handles game logic and graphics, but surprisingly not much else. A Z80 — a CPU introduced a decade before the Genesis/Mega Drive — is used for reading the state of the game pads, and playing audio.

Interestingly, the Sega Genesis / Mega Drive contains most of the components of Sega’s earlier console, the Sega Master System. With the addition of a Power Base Converter, Master System games can be played while the 68000 CPU is in idle.

The  Architecture of the Super Nintendo

The SNES is a different beast entirely. Everything is controlled through the 5A22 / 65816 CPU. The controllers are fed right into the data lines of the 5A22, and DMA instructions are able to shuttle data between the two slightly different Picture Processing Units.

An interesting difference between the two consoles are the connections between the cartridge slot and various peripheral chips. Nearly the entire cartridge connector of the Sega machine is dedicated to the address and data lines for the 68000 CPU. While there are a few control signals thrown in, it’s not enough to allow the cartridge direct access to the video display unit or the FM synthesis chip.

The cartridge connector for the SNES, on the other hand, has direct access to one picture processing unit and the audio processor. The exploitation of this capability was seen in games ranging from Star Fox with it’s SuperFX chip, to Mega Man X games with its math coprocessor, to Super Mario RPG: Legend of the Seven Stars and its Super Accelerator 1 chip that is basically an upgraded version of the main SNES CPU, the 5A22.

Comparative designs, and who won the console wars

Time to make a holistic analysis of each competing platform. By far, the SNES is a more capable console; its cartridges are able to send data directly to the PPUs and audio processors, it’s faster, and there’s more work RAM, vRAM, and audio RAM.

The Genesis / Mega Drive may be seen as more expandable thanks to the Sega CD (the first CD-ROM based game console, the Sega 32X), an upgraded coprocessor for the Genesis, backwards compatibility with a Master System Power Base converter, and a number of strange cartridges like Sonic and Knuckles with ‘lock-on’ technology. However, it’s actually the SNES that is more expandable. This is most certainly not the conventional wisdom, and the difference is due to how expandability was implemented in each console.

To add additional capabilities to the SNES, game designers would add new chips to the game cartridge. Star Fox famously exploited this with the SuperFX chip, and the list of SNES enhancement chips is deserving of its own entry in Wikipedia.

In comparison, the Genesis / Mega Drive could only be expanded through kludges – either through abusing the ASIC chip between the 68000 and Z80 CPUs, or in the case of the 32X add-on, bypassing the video display unit entirely.

In any event, this is purely an academic exercise. Games sell consoles, and Nintendo’s IP portfolio – even in the early 90s – included characters that had their own cartoons, live action movies, and cereals.

While this academic exercise is completely unimportant today – there probably won’t be a game console that ships with cartridges any more – it is an interesting case study on extendable computer design.

A few weeks ago, I was browsing Tindie on one of my daily trawls for something interesting to write about. I came across something I hadn’t seen before. The Mensch Microcomputer is a product from Western Design Center (WDC) that puts a microcontroller based on the 65xx core on a small breakout board.

I’ve played around with some of WDC’s tools and toys before, back when the sent me a few dev boards to review. They’re cool, and I have considered building a little breakout board for this weird cross between a microcontroller and a system on a chip. Life gets in the way, and that project sat on the shelf. The Mensch, however, was cheap and well into impulse purchase territory. After buying one, one of the VPs at WDC asked if I’d be interested in doing another review on their latest bit of hardware. Sure. I got this.

A Brief Overview of the WDC Catalog and Why It Matters

Western Design Center is the bearer of the 65xx series of CPUs, and the related peripheral chips. If you’ve ever used an Apple II, Nintendo Entertainment System, an Atari 8-bit, a Commodore 64, a Tamagotchi, or met Bender Bending Rodriguez or a T-800 Terminator, you’ve run into a 6502 or something that’s sufficiently similar that any differences are academic.

The 65816, the follow-up chip to the 6502, can be found in the Super Nintendo and the Apple IIgs. This chip is odd; on startup, it is a 6502. Flip a bit in the register with two instructions and you have 16-bit registers, 24-bit address space, and a bunch of other goodies that you can’t fit into 3,500 transistors. The ‘816 is one of those chips that would have changed the world if it came out a few years earlier, but that’s a story for another time. If you want to build your own 6502-based single board computer, I would highly suggest you take a look at the 65816.

The days of Nintendos and Commodores and Ataris running a 6502 are long gone, but the 65xx ISA is still out there. It’s found in everything from toys to life support equipment to aerospace, and if you want to play around with these devices, you’ll need to learn some 6502 assembly. Want proof? The greatest hack ever – [Sprite_tm]’s Matrix of Tamagotchis – is just a server emulating a few 6502 cores.

These weird devices obviously aren’t using full DIP40s and the related support chips. Instead, they’re either using custom ASICs with licensed 65xx cores or one of WDC’s microcontroller offerings. The 65C134SXB (based on the ’02), and the W65C265SXB (based on the 65c816) are small chips at the intersection of a microcontroller and a system on a chip. This brings us to WDC’s latest offering, the W65C265WBX, or the Mensch microcomputer.

Digging into the Mensch

The Mensch microcomputer is built around the 65C265, itself a microcontroller built around the 65816. This is a small board, with only the microcontroller, a few passives, eight LEDs, and a few headers. Effectively, this is a breakout board for WDC’s ‘816-based micro, with only the bare minimum required to get the thing going. What we’re really looking at here is a cut-down version of the ‘816 microcontroller development board I took a look at a while ago.

Consider this a breakout board for the 65C265. On board, you have a full ‘816 core, a monitor ROM, a little bit of RAM, several serial ports, a bank of LEDs, and access to 16 address lines and 8 data lines. If you want to develop for the 6502 or 65816, that’s all you need. If you want more RAM, just grab some perfboard and wire it in. If you want to build a pocket-sized SID player, build a ‘shield’ for this tiny development platform.

Compared to its full-size brethren, the Mensch is not as capable. The W65C265SXB – the larger microcontroller development board based on the same chip – has 32kB of SRAM on a separate chip, a socket for a Flash chip, and a USB to serial converter on board. This is the cost-reduced version of WDC’s microcontroller offerings, though, and anyone who would want to build something with a 65xx core probably already has a USB to Serial converter sitting around.

The monitor ROM is exactly what you would expect, granting access to the chip via a terminal emulator. Here, you can input machine code, jump to an address, and let LEDs blink to your heart’s content. You can use Python to talk to this board. If you’ve ever wanted to play around with 65xx chips, this is the board for you.

Conclusion

When I reviewed WDC’s slightly more capable offerings, I lamented the cost of these single board computers and microcontroller development boards. Yes, they’re the best way to play around with the 6502. They are, arguably, the best way to learn assembly. This is a world of two dollar Arduinos, though, and it’s hard to compete on price especially with an American made and assembled board that doesn’t contain counterfeit chips.

Still, I applaud WDC’s efforts to get their chips in the hands of more hackers. There’s still a lot of cool stuff you can do with a 6502, and if some of these young hackers end up going into industry they’ll probably come across the 6502 core at some point in their career. This is a CPU core that just isn’t going away, even though dying caps and corroded contacts means our Apple IIs and Commodores are. This is a great little board, and I can’t wait to see what kind of projects will be made with it.

One of the better retro historians out there on YouTube is the 8-Bit Guy, and after years of wanting to do something like this, it’s finally happening. The 8-Bit Guy is building his dream computer, heavily inspired by the Commodore 64.

Before we go into what this computer will do and what capabilities it will have, it’s important to note the 8-Bit Guy is actually doing a bit of market and user research before dedicating a year or more to this project. He’s asked other famous retrocomputing YouTubers for their input on what their ‘dream’ retrocomputer should do, and they’ve come up with a basic list of requirements. The Dream Computer will be like working on a 1957 Chevy, in that all the registers are immediately available for peeking and poking. The computer will be completely comprehensible, in so far that one person can completely understand everything, from the individual logic gates inside the CPU to the architecture of the kernel. It’ll run BASIC.

In the age of the Raspberry Pi, one might ask, ‘why not go with a Raspberry Pi?’. To the 8-Bit Guy, the Pi is just a Linux computer. Other retrocomputing projects of a similar scope to this dream computer also fail: The Mega65, a project to resurrect the Commodore 65, will be too expensive. The BASIC Engine fails because it only does composite out, and it runs on an ESP anyway, so you’re shielded from the real hardware. The same problem exists with the Maximite in that the hardware is one layer of abstraction away from the interface. The C256 Foenix is probably the closest to meeting the design goals, but it’s far too expensive, and even without the MIDI ports, SID chips, and other interesting hardware, it would still be above the desired price point.

The ‘requirement’ for this dream computer is to use only modern parts, have VGA or HDMI video out, a real CPU, preferably a 6502, use no FPGA or microcontrollers, and can run Commodore Basic. Also, this computer would cost about $50, with $100 as the absolute, maximum limit (implying a BOM cost of around $15-$25). This is absolutely, completely, astonishingly impossible. I would be deceiving you if I did not mention the impossibility of this project happening with the stated goals. This project will not meet the goal of selling for less than one hundred dollars.

That said, there’s no harm in trying, so The 8-Bit Guy is currently working with a few dev boards, specifically one designed around the 65816 CPU. The 65816 is an interesting chip, in that it is a 6502 until you flip a bit in a register. It has a larger address space than the 6502, and everything from the World of Commodore should be (relatively) easily ported to the 65816. Why was this CPU never used in Commodore hardware? Because a Western Design Center sales guy told a Commodore engineer that Apple was using it in their next computer (the Apple IIgs). The option of Commodore ever using the ‘816 died then and there.

If you’d like to help out on this computer, there is a Facebook group for organizing the build. This Facebook group is a closed group, meaning you need a Facebook account to login. Unfortunate, but we’re looking forward to a year of updates around this dream computer. Building a computer that meets the specs is impossible, but we’re more than eager to see the community try.

There are hundreds of modern, retrocomputing projects out there that put ancient CPUs and chips in a modern context. The Neon816 from [Lenore] is perhaps one of the most impressive projects like this we’ve seen. It’s a classic system in a modern form factor, with modern video output, mashed together into a MiniITX motherboard.

The powerhouse of this computer is the Western Design Center W65C816 CPU. This is the second generation of the venerable 6502 CPU, the same chip found in everything from the Commodore 64 to the Apple II to the Nintendo Entertainment System. The 65816 is a 6502 at start-up until you flip a bit in a register, at which time the signalling on the address bus becomes much weirder. We’ve seen some single board computers based on the 65816 before and The 8-Bit Guy has a few ideas to build a computer around this CPU, but for the foreseeable future work on that will be trapped in development hell.

Of note, the Neon816 will feature DVI output (I guess technically you can just run the analog signals through the connector), a PS/2 Joystick input, two Atari / Sega joystick ports, MIDI in and out, a PC-style floppy disc connector, and a Commodore serial bus. It’s a hodge-podge of classic retrotainment, all in a single MiniITX motherboard.

The key other feature of the Neon816 is an FPGA, specifically a Lattice XP2 8000 LUT chip that is used for video and audio. This is combined with 1MB of main RAM (looks like a simple SRAM) and 128k of Flash storage for the ROM. There’s also an SD card in there for storage.

Right now, [Lenore] is populating the first prototype board, and we can’t wait to see some video generated with this impressive little system.