MITS 8800B CPU Board

[Randy McLaughlin]

From: "Dwight K. Elvey" <dwight.elvey at amd.com>
Sent: Monday, June 13, 2005 7:12 PM


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

It is also easy to generate mwrite with a chip or chips glued upside down on 
the CPU card with no "real" modification to the board.  By no real 
modification I mean no cutting of traces just solder tack a couple of wires.

I'll see about looking it up, many CPU boards have mwrite as an option.


Randy
www.s100-manuals.com