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MyCPU – Homebrew Computer from Discrete Logic Gates (thtec.org)
257 points by lainon on May 16, 2019 | hide | past | favorite | 37 comments

Ben Eater has a most excellent Youtube series in the same vein.


He even sells a kit with all parts and schematics included. It's easily one of my favorite projects of all time and has inspired me to continue learning more.

It's not close to MyCPU's level of complexity but is great to get you started.

Amazing! A computer made without microprocessor... or a processor made of TTL circuits.

He has remade a system similar to the core of the great 1970's Xerox Alto / Xerox Star series :-)

I never thought someone would remake a processor this way. I love that kind of madness !

[edit: use the site backup if it fails to load: http://mycpu.thtec.org/www-mycpu-eu/index1.htm ]

:) There are many (it's a thing):

https://hackaday.io/projects?tag=CPU (Some are FPGA, most are TTL) Including two risc-v implementations (one seems stalled):

https://hackaday.io/project/18491-worlds-first-32bit-homebre... (No activity for a while now) and https://www.youtube.com/playlist?list=PLEeZWGE3PwbansoxKjjMK...

One I am particularly interested in is the Gigatron:

https://hackaday.io/search?term=Gigatron&category=project%20... (Especially now that there's real IO being hacked in)

http://www.homebrewcpu.com/ is wire wrap 16 bit computer that in fact serves the web pages and has telnet access.

Bill Buzbee is a goddamn legend

omg, Homebuilt CPUs WebRing still working.

Big Mess o' Wires is another good one: https://www.bigmessowires.com/bmow1/

Walter Belgers and Marcel van Kervinck's Gigatron (https://gigatron.io/) is also interesting. It's spirit is to use only 70's technology to keep the system "learnable" from the ground up, although they sometimes violate this rule for peripherals outside the main system.

Walter gave a talk recently about it: https://www.youtube.com/watch?v=rbaAmnhZAis

This is definitely on my "list of things I've always wanted to do but I realized man is mortal and I have to prioritize". I'm a personal computing enthusiast and it doesn't get much more personal than designing and building your own architecture.

not to mention the $50~200k on specialized test equipment you will have to buy to even start on this path.

Nobody mentions this.

In every wire rat nest CPU picture, there is always several thousand dollars of digilent and HP gear out of the frame.

I did this for a living in the 1980s--CPUs from TTL. My artistic side wants to build a small running computer from all TTL inside a plexiglas cube with all the chips glued to the walls and the interconnecting multi-colored wires exposed with a small display of something.

I love these homebrew CPU projects. I saw one one in person and was amazed (and impressed by the insane dedication as well as the madness of wire-wrapping 1970s-era TTL components into a CPU) - then a year later I saw two of them!! Then I saw a third.

I believe the first two I saw were MAGIC-1 and BMOW (Big Mess o'Wires). I also really liked the MOnSter 6502, a beautiful board-level reimplementation of the 6502 in surface-mount discrete components, with LEDs on the data lines and optional slow/single-step clocking.

Also relevant: the nand2tetris.org course, and Niklaus Wirth's TRM/RISC-3 (not to be confused with Berkeley RISC-I or modern RISC-V) FPGA implementation. Notably TRM/RISC-3 is incredibly simple but can run the whole Oberon system.

In the modern era, I think FPGAs are the killer platform for computer architecture experimentation. There are multiple free MIPS implementations for FPGA and of course there is great OS/compiler support for MIPS.

Before I saw the German, I already had a feeling it was --- I'm not sure why, but I've seen Germans use that style of page a lot (another example: https://www-user.tu-chemnitz.de/~heha/basteln/PC/USB2LPT/ul-... ). That and the encouragement to build one yourself stood out.

This one looks very similar to a 6502, and seems to be much smaller than another semi-famous discrete homebrew computer, http://www.homebrewcpu.com/ --- that one only runs at half the clock speed, but the performance seems comparable.

I wonder if dennis-mycpu is still around to answer questions? This is an awesome build, and demonstrating it by serving the site is a fantastic idea.

Another similar project in addition to the ones mentioned here is the BMOW: https://www.bigmessowires.com/bmow1/

A nice project, there are more homebrew CPUs - physical or FPGA cores. But they are often complex. I was finally able to understand the basics of CPU workings from an awesome book http://www.buthowdoitknow.com/ and related video https://youtu.be/cNN_tTXABUA

See also: homebrewcpu https://www.homebrewcpu.com/ and megaprocessor http://www.megaprocessor.com/

All those fancy-pants semiconductors...

Here’s a real computer. http://web.cecs.pdx.edu/~harry/Relay/

I took a compilers course from Prof. Porter, and at the time he invited undergraduates to write a simulator for his relay computer. I remember thinking, "why in the world would I want to do that? I want to work on the next big thing!" Fast forward to now, I've never worked on the Next Big Thing, and am instead slowly, though enjoyably, building Ben Eater's 8-bit SAP-1 when I have some free time. It sort of feels a bit like building a ship in a bottle. I just wish I had taken Professor Porter up on his offer and maybe scratched an itch when I had a little more energy and free time.

You can now buy one:


(apologies for the self promotion..)

I have been looking at your board on Tindie! Alas, I don't think it should be my first major soldering job (if you don't count the board I stuffed 25 odd years ago that my friend had to fix for me)

I'm curious does anyone know what the last substantial commercial computer that shipped with CPUs made out of discreet logic chips like this was?

Apologies if this is a silly question but how does this differ from other homemade cpus that appear every so often?

A big one is that the page is served by the CPU it describes.

Web ring is best ring.

> The website is slow because it is served by a MyCPU

I would imagine now that it's on the front page of HN, that poor MyCPU is now on fire

no ssl and a bunch of frames, that ultimately failed to load.

HN hug of death at the lowest amount of votes on the post.

The post made it to the frontpage, no surprise new visitors get greeted with "Server busy" now.

Alternatively, the official mirror http://mycpu.thtec.org/www-mycpu-eu/index1.htm

Thanks! Since it's still down we'll update the link from http://mycpu.eu/ to this.

In the age of GitHub pages, Netlify and who knows how many other unlimited bandwidth web hosts - how on earth do people still manage to get their sites slashdotted?

By intentionally serving it from a computer that’s essentially from the 70’s

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