11 Nov
2005
11 Nov
'05
11:29 p.m.
Stegeman, Henk HJ SITI-ITIBHW5 wrote:
Hi Jos,
I fully agree with you. Building your own CPU is really an exciting project.
I took me more then 3 months to debug my 110 TTL CPU with
256 words of micro code of 48 bits.
I have been trying since I was about 12. Now I am a old GEEK and still
trying to save
my pennies up parts. I can never get a clean TTL design under about 300
chips for the
data path and 150 for the control unit.
See: http://www.anysystems.nl/hjs22.html for some
pictures and the
reference card.
This is a nice CPU.
>What surprises me about the home-built computers from scratch is the
>lack
>of imagination when it comes to architecture. Most are basically
>one-address-cum-accumulator designs. It would seem that larger
>register
>files are much easier to build nowadays and would open up the door to
>some
>2 and 3-address designs.
>
>
I would bit slice would be better for that route, it is lot of
instruction types
that add up with multi-address opcodes.
In 1974 Elektor magazine started a series of DIY articles that described
an extensible ( 12 bit or 16 bit width ) three address, clockless
computer.
TTL based, with a shiftregister based memory. (6 or 8 512x2
shiftregisters .)
Living in Canada I was Computer deprived .... I'll read the DIY stuff
now and maybie build it
in 20 years :)