VE3OIJ Amateur Radio

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4 bit computer built from discrete transistors

Posted: 08 Jan 2016 11:49 AM PST
https://ve3oij.squidzone.ca/2016/01/...e-transistors/


I started this project as an attempt to teach myself about how computers
worked. As such comments, useful links, or anything else related would be
appreciated. Prior to this my experience in electronics was mostly
microcontroller based. The computer is Continue reading

The post 4 bit computer built from discrete transistors appeared first on
VE3OIJ Amateur Radio.

"VE3OIJ via rec.radio.amateur.moderated Admin"
wrote in message
...

VE3OIJ Amateur Radio

///////////////////////////////////////////
4 bit computer built from discrete transistors

Posted: 08 Jan 2016 11:49 AM PST
https://ve3oij.squidzone.ca/2016/01/...e-transistors/


I started this project as an attempt to teach myself about how computers
worked. As such comments, useful links, or anything else related would be
appreciated. Prior to this my experience in electronics was mostly
microcontroller based. The computer is Continue reading

The post 4 bit computer built from discrete transistors appeared first on
VE3OIJ Amateur Radio.


I didn't quite get down to that level, but 1973 onwards, I did my own 8 bit
computer from basic TTL chips. I had 128 bytes of memory based upon 4
manufacturer's
samples of 256 by 1 static RAMS, with a shift reg to get byte wide.*****

It ran OK at 1 instruction per sec, but trying to go fast, it fell over, and
then in about 1978 along
came the 5V-only Z80 and it became pointless to continue.

Oddly enough, I've only just disposed of the last fragment of it, the former
PDP-like
aluminium front panel, which had become part of the bridge across the pond
for my 16mm
garden railway that I have just sold off!

***** I had also obtained a 48 by 4Kcore memory from the Marconi Leo series,
but
it would have been a lifetime's pocket money to get the electronics to drive
it, even though
that had been part of my Uni degree; but who needs experts on half-select
noise these days?!

(Although I still have in the junk box the 8 FET-input op amps got in
readyness for
the sense amplifiers)

Happy Days!