RE: [N8VEM-S100:949] An 80386 S-100 Board.

["John Monahan" <mon...@vitasoft.org>]

I actually spent some time reading up on the 386EX and was considering it
instead of the 80386, but each time I gave up. It's just too much on a
nightmare to configure the thing.   Also I think it uses an DMA controller
for refresh. That would not work in our case because once the 80386EX is no
longer the bus master it is held in a reset state (or possibly hold state). 

John


John Monahan Ph.D
e-mail: mon...@vitasoft.org
Text:    mon...@txt.att.net


-----Original Message-----
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On
Behalf Of Rob Doyle
Sent: Saturday, July 14, 2012 10:20 PM
To: n8vem...@googlegroups.com
Subject: Re: [N8VEM-S100:949] An 80386 S-100 Board.

On 7/14/2012 7:50 PM, mike wrote:
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> I don't think I have seen anybody mention it yet, but has the i80386EX 
> been considered? It has a built-in DRAM controller.
>
> I see there's a few up on ebay right now for a reasonable price.
>
> They are SMD however so there's that issue.
>
> It was designed for embedded systems so it hassome peripherals on-chip 
> including an AT style bus interface which I would think would tend to 
> help simplify the interface with S100 bus.
>
> Anyway, an option I guess.
>
> I'll see if the datasheet attachment works, if not, it should be not 
> hard to find.
>
> - --Mike

The problem with the 80386EX is it is specifically designed so that you
can't run vanilla DOS on it.  The internal peripherals are all intentionally
incompatible.

Rob.