[clug] Homebuilt CPUs

Bob Edwards bob at cs.anu.edu.au
Tue Sep 26 22:54:41 UTC 2017

On 26/09/17 22:02, steve jenkin via linux wrote:
> Warren Toomey used to teach at ADFA, will be familiar to some of you.
> He’s built an 11-chip design with "7400-style chips” (and 1kbit RAM and some ROM)
> <http://minnie.tuhs.org/Programs/CrazySmallCPU/index.html>
> I didn’t know that ‘this was a thing’ until tonight.
> Seems there’s a whole community in this "Homebuilt CPUs WebRing”.
> --
> Steve Jenkin, IT Systems and Design

Hi Steve,

I'm partway through building one entirely out of bipolar (and,
possibly in the future, Field-Effect) transistors:


The 512-bit ROM and 8-byte RAM cards are real, but not fully tested
yet. I am trying to determine how fast I can clock them. (Each RAM
bit needs 6 transistors to be able to store a bit, read it and to
change it, so lots of transistors just for 8 bytes...).

My first aim is to build a CPU that can run BF programs. Will need
quite a few 8-byte RAM boards for that...

My design is intended to be fully transparent - any signal can be
probed at any time to ensure it is not "hidden". So, no ICs... Also,
fully static, so the thing can be stopped at any point and inspected
with no loss of data.

Started working on it over 5 years ago - maybe I'll finish it one day


Bob Edwards.

> 0412 786 915 (+61 412 786 915)
> PO Box 38, Kippax ACT 2615, AUSTRALIA
> mailto:sjenkin at canb.auug.org.au http://members.tip.net.au/~sjenkin

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