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RE: [N8VEM-S100:7749] Re: A new Z80 based SBC to get beginners started on the S100 bus
Please see the updates on the S100Computers site
-----Original Message-----
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com]
Sent: Saturday, October 17, 2015 11:43 AM
To: n8vem...@googlegroups.com
Subject: RE: [N8VEM-S100:7749] Re: A new Z80 based SBC to get beginners started on the S100 bus
John,
Thank you for the reply. I was hoping that a board similar to the TDL ZPU board would work in most situations. A few years ago I built a small IDE interface for the SWTPc SS-30 bus, and later a "stand alone" Z80 board to communicate with a PC via a serial bus. The Z80 board used shadow Rom and a large Static Ram to hold a ramdisk. It was on an EspressPCB Miniboard using TTL style components.
I like the TDL board documentation, and hope the basic design would work with most S100 boards. I don't think the variable frequency oscillator option would be needed, and would use a commercial oscillator for simplicity. I assume that adding a small amount of Rom and Ram plus a USB chip would be practical.
One problem is finding an S100 chassis. Those on Ebay end up going for about $1000.
- Frank
--------------------------------------------
On Wed, 10/14/15, John Monahan <mon...@vitasoft.org> wrote:
Subject: RE: [N8VEM-S100:7748] Re: A new Z80 based SBC to get beginners started on the S100 bus
To: n8vem...@googlegroups.com
Date: Wednesday, October 14, 2015, 1:10 PM
There are numerous ways
to do this Frank, I opted for the most basic hardware approach using 74LSxxx. This allows for very simple hardware debugging. Later one can easily use and learn how the S100 bus signals are generated/formed etc. using a scope/logic probe step by step. The challenge with boards like this is getting them working with older pre IEEE-696
S100 boards found in many S100 boxes. Few even old Z80 boards worked with all boards.
Having spent the best part of a year on a CPLD based 80386 and 80486 based S100 boards I can tell you it's not as easy as you may think.
That said if you have time I'm sure some
S100 users would appreciate a CPLD Z80 board.
John
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