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FPGA vs retro hardware

My roundup of Commodore motherboards turned up on a vintage computer discussion board. A minor aside that I mentioned in passing turned into a major topic of discussion. And then the conversation turned in an entirely different direction. What about going with an FPGA solution, rather than vintage hardware? With an FPGA approach you can be certain you’re getting what you want. But what are the drawbacks of FPGA vs retro hardware, if any?

A purist will object to modern FPGA approaches, usually for more than one reason. But there can be practical advantages to an FPGA solution, and it’s also possible to blend it with a more traditional approach.

FPGA is not the same as emulation

FPGA vs retro hardware

An FPGA can be reprogrammed to implement vintage computer chip designs on new hardware, giving you old chips without the reliability and scarcity issues.

The first thing to get out of the way is the question of FGPA vs emulation. FPGA adherents stress they aren’t the same thing. The difference may or may not be enough for a purist. But there’s enough difference that an FPGA approach is good enough for a class of hobbyists who aren’t happy with the results of emulation.

Emulation is implementing another computer in software. Basically, it allows you to run a program that creates a sort of virtual machine inside another computer. I can (and sometimes do) use the VICE or WinUAE emulators to run Commodore 8-bit or Amiga software on my Windows laptop. You can also load a bunch of emulators on a Raspberry Pi, plug it into a TV, and emulate dozens of retro systems with a box that’s no bigger than two decks of cards. And it’s cheap. You can set up a Pi emulation rig for well under $50. Another common approach is to buy a cheap laptop, such as one of the many $150 Black Friday specials, and dedicate it to emulation.

FPGA is implementing a computer in hardware. An FPGA is a computer chip that allows you to lay out its logic gates and then it becomes that chip, at least until you program it with a new layout. I can load a 6502 processor core in an FPGA, and that turns that FPGA into a 6502. I could then plug that FPGA into a Commodore VIC-20 in place of the 6502, and the VIC-20 wouldn’t know the difference.

But there’s enough room on a modern FPGA to implement more than a 6502. You can implement the whole computer. And then you have a modern implementation of the old design, running on new silicon that hasn’t been subjected to the ravages of time.

Advantages of the FPGA approach

The advantage of the FPGA approach is clear. You have a brand new chip. It doesn’t matter if the originals were discontinued in 1992. You can burn as many FPGAs as you want. And it behaves like the original. With emulation, you’ll get timing issues and lag that usually aren’t noticeable, but it’s not going to be perfect. With FPGA, the timing can be perfect.

An FPGA setup like MiSTER costs more than emulation, but it’s cheaper than the real hardware. Some of my retro hardware is my own stuff left over from the 80s and 90s, and I bought a lot of it between 2005 and 2012 when no one wanted it and it was cheap. But today, it’s not unusual to spend $200 or more putting together a nice example of whatever 1980s machine you want. The computer itself may not be expensive, but by the time you add all the peripherals you want, you can get north of $200 fairly quickly. An FPGA solution costs less than building two nice vintage computer setups would.

Not only that, an FPGA solution makes systems accessible to you that otherwise wouldn’t be. I’ve never seen a BBC Micro or a Sinclair ZX Spectrum. Those 80s British micros never made their way to the middle of Missouri where I live. But I could use an FPGA implementation of them and it wouldn’t matter. The expense of importing them and the space they take up all go out the window. And if your interests change, you eliminate the problem of selling the machine, possibly at a loss, and then having to procure the machine that interests you now.

Disadvantages of an FPGA setup

So if the MiSTER is so great, why don’t I have one? It may sound strange, but I like being around the old machines more than I like using them. Sure, it’s fun to fire up an old game on my C-64, Atari 800, or Amiga 500 and play a few rounds. But I don’t do that every week. I certainly can fire up M.U.L.E. and play it for two or three hours straight. The last time I did that was six months ago.

And nostalgia’s a funny thing. It’s a multisensory experience. I remember what the C-64s I used growing up looked like. The keys had a distinct feel. The Atari 800 and Apple IIe keyboards feel different. The disk drives were different. And sometimes frighteningly alike, too. And the VIC-20 looks a lot like the 64, but the force it takes to plug in and unplug the cartridges is much higher. Some of those subtleties about the originals aren’t there when all you have is a modern recreation of it.

I like writing about them, and having examples of the real thing right there makes it easier to write about them.

And part of it is what I do with the machines. I work from home. And I actually keep most of my machines in the room I work out of. When I go on a Zoom call with video, you see my Amiga 500 and my C-64 behind me. I grew up with this stuff, and most people who’ve worked with me for any length of time figure out I’m a technologist. I don’t just work on computers because the job pays well.

And although rare, there are instances where you can’t perfectly replicate original hardware in FPGA. The C-64’s SID chip contains analog components that current FPGAs can’t replicate. The MiSTER won’t sound quite like a real SID. For some people that’s not a big deal, but for others it could be a showstopper. But that also depends how important the 64’s core is to you.

Blending the FPGA and real hardware approaches

Of course, nothing says you can’t blend the two approaches. I could, and probably eventually will, get an FPGA setup so I can run systems like the Spectrum and BBC Micro that I’ll never see here in the States. For that matter, I could run an Amiga 1200 core on it too, given the scarcity and high price of that generation of Amiga here.

And I may very well run systems like the VIC-20 on it too, just for convenience. Sure, I have a VIC, but it’s on the wall, so I could just fire up the FPGA box if I want to play a quick game of Choplifter. And it saves wear and tear on my actual C-64 to use something more modern most of the time. I’ve got the real thing when what I want to do calls for it, and can use the FPGA when it’s not necessary. And in the meantime, the vintage hardware remains in good operating order.

So the FPGA brings a very-close-to-reality experience to the hobbyist, along with systems that would otherwise be inaccessible. It doesn’t preclude collecting hardware that has sentimental value to you. But by the same token, it can give you the benefit of collecting everything without having to collect everything, if anything at all.

It’s a modern reproduction. But that’s not all bad.

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