RE: [N8VEM-S100:2126] Going back in time - The Cromemco Dazzler Board

My interests lay with Popular and Radio Electronics. Which is why I'm into the Altair and IMSAI. I took a quick look, this board is featured as a construction project in PE, Feb 1976. Of course the schematics and full construction details were not given in the PE magazine, you needed to send away for them. I just downloaded them from your web site, but I would love to get an original copy of them.

At a glance, it doesn't look complicated. Hold the processor, get the Hold Ack, put your address on the bus... I'm guessing this board also deactivates CPU card's control of the S-100 Address bus & Control bus. I found that odd that the "Hold" circuit of the 8080 CPU board did not automatically put the S-100 bus drives into Hi-Z.
However, reading your recent entry, it caught my eyes that this Dazzler board accesses external ROM, and it wouldn't work for all memory boards... now this is makes it look a little more complicated.

:)J

From: mon...@vitasoft.org
To: n8vem...@googlegroups.com
Subject: RE: [N8VEM-S100:2126] Going back in time - The Cromemco Dazzler Board
Date: Mon, 30 Dec 2013 21:16:01 -0800

Actually an exact copy would not be hard Josh. The problem is however, it’s unclear how Cromemco implemented DMA to access RAM. The board does not actually work with most memory boards I have here. Fortunately is does with our own RAM+ROM board. A bigger problem is the CPU. I suspect it would not work with most current high speed (8- 10MHz) Z80 boards many of us are using. You would probably have to stick to the 4MHz Cromemco “ZCPU” board.

That’s for a direct clone. They supplied the schematic, perhaps we could do a work around with the circuits. I have not studied it however. It’s not going to be easy.

John

From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Pete Plank
Sent: Sunday, December 29, 2013 2:00 PM
To: n8vem...@googlegroups.com
Subject: Re: [N8VEM-S100:2125] Going back in time - The Cromemco Dazzler Board

How hard would it be to create a Dazzler clone? Any hard to find parts in it?

Pete

On Dec 28, 2013, at 8:34 PM, Crusty OMO <crus...@hotmail.com> wrote:

John,

Thanks for the video. Yes, I remember the era. I was a young teenager building my ELF and was impressed with the black and white graphics in the ELF Project part IV but amazed with the capability of the dazzler (of course, I could never afford one back then). I am interested in getting one of these Dazzler boards for my collection because Popular Electronics had a nice write up article about it. Did you see that article? I think I scanned it, should be available on Rich Cini's web page. These boards don't come up for sale very often, but if you are ever inclined to sell yours... I'll tell you that my collection is based on the computers featured in Popular and Radio Electronics.

Cheers,
Josh

Date: Sat, 28 Dec 2013 18:59:55 -0800
From: mon...@vitasoft.org
To: n8vem...@googlegroups.com
Subject: [N8VEM-S100:2120] Going back in time - The Cromemco Dazzler Board

Just for the heck of it I spent some time setting up a system that allowed me to run the famous Cromemco Dazzler board. For those that may not have been around at the time, this was the first S-100 bus video board. While its video resolution by today’s standards is primitive, at the time it caused a sensation and was responsible for many of us getting into “home computer systems”.

To bring back memories I have a short video demo here:-

http://www.s100computers.com/Hardware%20Folder/Cromemco/Dazzler/Dazzler.htm

Enjoy!

John

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