Build an 8-bit TTL computer

Very rarely do we see an Instructable so complete, and so informative, that it’s a paragon of tutorials that all Instructables should aspire to. [8 Bit Spaghetti]‘s How to Build an 8-bit computer is one of those tutorials.

[8 Bit Spaghetti]‘s build began on his blog. He originally planned to build a 4-bit computer but decided a computer that could only count to 15 would be too limiting. The build continued by programming an NVRAM as the ROM on a breadboard and finally testing his bundle of wires.

What really makes [8 Bit Spaghetti]‘s special is the Instructable – he covers just about all the background information like the definition of a Turing machine, a brief introduction to electronics and logic chips, and binary numbers. Even though he’s doing some fairly complicated work, [8 Bit Spaghetti]‘s tutorial makes everything very clear.

The computer isn’t quite done yet – there’s still a few nixie tubes to add – but we couldn’t imagine a better project for the budding electronic hacker.

Comments

  1. Stok says:

    I’d love to do this sometime, it would be awesome.

    Maybe when I have a little spare time I’ll get started…

  2. jcg says:

    Anyone care to hazard a guess how big this would be on a PCB? I think it would make an awesome art piece. Add a led on every line, and run it at .5 Hz.

    • heine says:

      That’s a cool idea. Putting one on every line would look confusing, maybe just the registers? And a few special ones for encoding the opcode?

      • bio says:

        a big blinky art peace is not supposed to make seance XP

        i would love to make one of these dead buged on to some plexy glass with no shortage of LEDs as a wall art peace doing one simple but obvious digital task … sorts like a Rube Goldberg machine of sorts

        like it starts with a 0.5 hz tick and it counts 1-9999 on quad 7 segments with an led on all the 1/0s :P

    • CoConut says:

      If this was a facebook post, I would Like it.

      LEDs on every line, huge PCB in a deep frame with a fan…

      It’d need something useful to do, otherwise it’s just a overly complicated piece of art. Maybe program it to monitor a fishtank or something.

  3. andygoth says:

    “Any and all outputs that are connected to the bus have to be completely disconnected while inactive or else they would merge with each other and result in erroneous output.”

    Examples of erroneous output include sparks, fire, and magic smoke.

  4. bio says:

    i love how in his “build your own computer from scratch” how-to he had to explain basic electronic circuts XP

    but i did love the sight of that circuit board … did it bring anyone else back to the wonderful days of wire wrapping?

    • Rollyn01 says:

      Yes, his wire porn definitely got me “wired”. On the less perverted side, I would love to throw something like this together as a risc computer. 4-bit op codes are too low for me. Plus I would throw in some mantissas for floating point math and binary compressions.

      • bio says:

        yeah i was thinking of risc atleast if i was to make one of these … i was only ever trained on risc and i386 … and unless im making a desktop risc will work justttt fine :P

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