13 Nov
2005
13 Nov
'05
6 p.m.
Subject: Re: semi-homemade micro
From: Scott Stevens <chenmel at earthlink.net>
Date: Sun, 13 Nov 2005 19:11:13 -0500
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
On Sun, 13 Nov 2005 17:42:02 -0500
Allison <ajp166 at bellatlantic.net> wrote:
(echoing a sentiment expressed here earlier) Perfectly good DECmateIIs??
No I mean defunct ones or as I found a few as just the main board from
DMII/III as salvage (no case PS or ??). Good ones work and you use
them as is and enjoy them. Besides a working DM runs OS278 and WPS
both useful!
Subject: semi-homemade micro
From: compoobah at valleyimplants.com
Date: Sun, 13 Nov 2005 11:22:23 -0600
To: <cctalk at classiccmp.org>
All the talk about building a mini from TTL got me thinking about homebuild
micros, and what one would look like if I decided to build one
(been playing with my IMSAI, too, which probably accounts for some of it)
=0D=0A
Using RTF??
RISC would be out, due to difficulty of assembly
coding,
and 8086 seems a bit dull.
Z-8000, TMS9900, and RCA1802 seem unavailable, and 6120 doesn't
have many registers.=0D=0A
The 1802s are available as is the 6120 (spare time gizmos has kitted both).
(Harris makes the 1802 and 6120.) old 1802 can be salvaged from EFjohnson
made VHF mobile radios of early 80s vintage and 6120s from defunct
DECmateII/IIIs.
I have 6100s, too, if you want a scaled back version.
The 6100 is a
great 'easy' first processor to use- all static CMOS with very lax
timing requirements for the clock signal. 12 bits, though. And,
of course, the PDP-8 instruction set.
PDP-8 interuction set reminds me how programming can be fun.
Enough of the things needed to write practical code but not
one drop more. That and you can remember the whole instruction
set and it's opcodes!
I have a base 6100 machine, Intersil super sampler with with
4kram and the monitor, (rom can be dropped after loading ram
low).
Allison