MITS 8800B CPU Board - test-drb@ccmp.vtda.org

14 Jun 2005

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Date: Mon, 13 Jun 2005 20:44:14 -0400
From: "Allison" <ajp166 at bellatlantic.net>
To: cctalk at classiccmp.org
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Subject: Re: MITS 8800B CPU Board
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>
>Subject: Re: MITS 8800B CPU Board
>   From: "Dwight K. Elvey" <dwight.elvey at amd.com>
>   Date: Mon, 13 Jun 2005 17:12:04 -0700 (PDT)
>     To: cctalk at classiccmp.org
>
>>From: "river" <river at zip.com.au>
>>
>>Hi,
>>
>>Thanks for your replies. I found the relevant information.
>>
>>I have an extensive inventory and can source the parts and get this poor, 
>battered board back to its old self again. However, looking through the doco I 
>noticed that the 8800B requires a display/control and interface boards. A 
>question for those of you that own a MITS8800 - does it need those boards for  a

...
 >turnkey system? Can I plug the CPU board into the
backplane and run it without 
>the d/c and i/f cards, assuming I set up the ROM and RAM cards for the system? 
>If not, (since I do not have the d/c and i/f cards) I'll have to try and build 
>them from the cct diagrams I have obtained. This is do-able (but a lot of  work)

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 >if I can get my hands on some blank S100 w/wrap
boards, but I noticed there's  a 
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 >1702 EPROM chip and I'd need to get the memory
map for this chip to burn my  own.
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 >>
>>Failing that, and it's all too hard and bothersome for me, is there anyone 
that 
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  would need a
repaired 8800 CPU card for trade or anything similar?

rgds
river

Hi
 It should work on a turnkey. Almost everything goes
through the S100 bus. Only the direct connect of the
data bus goes directly between the panel and the CPU board.
I don't think that is needed. You will have to have code
residing at address 0000. This is not common. Most
expected a working front panel that could load a boot
address.
 Some ROM boards have a way to be at 0000 after reset
and then switch to someplace else once things are booted.
 Don't give up on it. When there is a will, there will
be a way.
Dwight 

Yes, you will have to have rom at 0000h though and Mwrite
was derived and delivered from the front pannel if memory
serves.  So that means ram will have to be set up to not
require Mwrite.  Either that or you will have to through 
something small together to create Mwrite.

As to mapping rom out once operational, thats a later problem.
It's fairly easy to do.

Allison 
Hi
 I've done this on my NC4000 based computer. It is nice
to have it all in clean RAM. One can do things like hot
patching code( not recommended for the faint of heart ).
Dwight