semi-homemade micro

Allison ajp166 at
Sun Nov 13 20:00:54 CST 2005

>Subject: Re: semi-homemade micro
>   From: Scott Stevens <chenmel at>
>   Date: Sun, 13 Nov 2005 19:11:13 -0500
>     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at>
>On Sun, 13 Nov 2005 17:42:02 -0500
>Allison <ajp166 at> wrote:
>> >
>> >Subject: semi-homemade micro
>> >   From: compoobah at
>> >   Date: Sun, 13 Nov 2005 11:22:23 -0600
>> >     To: <cctalk at>
>> >
>> >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.
>(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!  

>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 


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