Micro Beast: Self contained 8-bit computer kit in a box

Tangent on CollapseOS/DuskOS because this is the first time I've encountered this and it is very much up by alley:

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Being that it is for a post-Collapse world would be nice to see it ported to run on RISC-V (not trolling) because RISC-V is already the subject of "Computer Organization and Design RISC-V Edition" and very well documented, but also going to be increasing the architecture with the most resources through student, assignments, etc, but also to salvage from existing electronics.

Thought the author's timeline is 2030, which is a bit too soon for that, but by 2040 I think my argument holds.

You sent me on a Collapse OS and Forth rabbit hole. Apart from the technical appeal I like the sober writing style of its author and the website. I do not think the postulated collapse of global society is imminent but I am glad that this project exists.

Yeah, it really feels like people are going back to the pre-5150 personal computer era and looking at things from the ground up again.

This is especially exciting to me as someone juuuuuust old enough to have extensively used those machines (C64, //e, Atari 800, etc) when they were contemporary but now diving deep into an interest in the fundamentals of computing while in the middle of a completely different career. A project like this is specifically exciting because I could look at 8 bit computing from the ground up without having to worry about buying a vintage machine and a whole host of gremlins it might have built up over the years.

A lot of things came together over the last decade or two to enable ever-more-impressive 'maker'/hobbyist projects. Ubiquitous 3D printing, cheap PCBs, powerful CAD software available to hobbyists, YouTube's growth as an educational resource, excitement over FPGAs, super-affordable microcontrollers and single-board computers, and a big wave of 80s/90s nostalgia often giving it direction.

At the same time, modern 'mainstream' computing has become increasingly user-hostile, built to encourage spending, ad-views, and content consumption rather than experimenting and creating.

What are some other projects you've been excited by? Love seeing what people are capable of by indulging their passion.

This is a CP/M 2.2 installation, with the CCP loading from address D800h giving approximately 54Kb free for user programs. The system supports two 248K drives - Drive A is in ROM (and therefore readonly at present) and Drive B is in RAM.

Seen like that, you could have something like that on a C128, I guess.

Adding video is apparently quite difficult.

Apparently it's straight forward to breadboard a legacy CPU today and get serial I/O, which solves many ills. But getting video is a large wall to scale.

There have been several video solutions out there that folks have made. I think Ben Eater has a video of banging together something that can drive VGA (but not, necessarily, what one would consider "video" for a computer).

The original home 8-Bit computers were essentially video display systems that had some spare cycles to actually run some software. The fundamentals of the system design revolved around the video. Everything was a slave to the video clock cycle.

There is no real one chip device folks can drop on to a CPU bus and "get video", not that I've seen yet, especially not the way folk remember the 8-bit experience with memory mapped video. Even integrating something like the ubiquitous 6845 (which was used everywhere back in the day) is challenging, as it's not a one chip solution, plus, today, interfacing it to a generic HDMI monitor is a trick. (Also, I'm not sure today how availability of the 6845 is today.)

Even the Commander X16, which went through great lengths to reinvent the 8-bit experience, created their own video chip (FPGA I think), and it does not share video memory with the host 6502, it use a memory mapped I/O interface.

Then, of course, there's things like a Raspberry Pi 0, that (in theory) can be bought for $10. Tie that to the serial port, and host some software on it, and it can do all sorts of amazing things far faster than a 10MHz Z80.

The original creator of this kit (which by the way, looks like a really nice, well packaged kit) had this as an original goal:

  * Genuine 8-bit design, don't cheat with "support" processors that are more powerful than the main CPU.

Obviously, a Rasp Pi is quite disqualified from that. And, to be fair, I'm going to quibble, because the CP2102N chip they use for USB connectivity is likely a powerful CPU, more powerful than the Z80. You have to be to be able to drive USB 2.0.

But I can't condemn them for that, the addition of the UART talking to the CP2102N is a very good design. And adding USB to the system opens it to a huge variety of peripherals. With that clock chip, they can go to 56K baud, that's 5K Bps. That's fast for a floppy at the time. Slow for a hard drive, but overall not too bad.

At 10MHz, they might have got better transfer rates with a bit banged SPI USB driver.

... or Tetris

And DOOM of course.

> Are there no 32-bit CPUs with a simple architecture and easy programming model?

There really aren't. You could consider Arm (maybe with the simplified but 16-bit "thumb" instruction set), or MIPS, or RISC-V. Between all of those, it's rare to find bare CPUs; usually you get them in a system-on-a-chip, with things like DDR memory and other sophisticated peripherals built-in. You need complicated drivers and a bootloader, maybe even with signed payloads. Nothing as architecturally simple as wiring the address and data lines of a CPU into the address and data lines of some RAM or 7800 logic directly wired into a keyboard.

In principle those devices could exist, but as a hobbyist you can only really get your hands on hardware with that kind of conceptual simplicity by either programming it into an FPGA, or by using hardware that dates back to when that approach to computer design was cutting-edge.

edit: you could maybe consider some kinds of microcontrollers? The Parallax Propeller comes to mind.

The Motorola 68k series. A very nice 32-bit architecture that was fun to program. The downside, Motorola isn't making new ones, and I'm not sure who owns the property. Another nice 32-bit architecture was the VAX. It had the most regular assembly language I've ever seen, despite being a CISC architecture. But sadly, both are obsolete these days.

Probably not exactly what you’re looking for (since you mention “outdated”) but there are similar projects with 16 and 32 bit architectures, e.g. https://github.com/rosco-m68k/rosco_m68k

(Disclosure: I’m the designer and lead developer on that project).

You can hand clock a Z80. It is kind of magical.

If you want to learn how modern computers work, you should probably give up on the idea of building something yourself - since any modern architecture relies on busses, peripherals and processor functionality that are way beyond hand soldered kits. Get a Raspberry Pi and accept that even light switches run Linux these days!

More seriously, since the time of 8-bit CPUs, hardware has essentially split into deeply embedded system on chip designs (often ARM or RiscV cores) or monster multi-core 64 bit CPUs. The intervening 16 and 32 bit processors have largely been consigned to history (genuinely a shame - but that's the reason there are so few kits based on them). Ironically, it's the old Z80 and 6502 that are still being manufactured today in volume and at low cost as a convenient building block for simple "computer" devices.

So, no - this sort of kit does not teach you how your M3 Mac works - but it does provide you with a system that you can completely understand and control, that you can build your own peripherals for, that you can write a complete operating system for, or games and programs, that you can have the satisfaction of building yet still has the basic architecture of any modern computer. And for the sort of task you're likely to undertake, it's surprisingly capable.

Alternatively, if you want hardware with a simple programming model that abstracts the difficult stuff away, get an Arduino. That's really the choice you're making - either 'close to the metal' coding on older CPUs, or the modern approach of abstracting everything into software. Both are equally valid.