RE: [N8VEM-S100:1757] IMSAI 8080 CPU card replacement

Guys, I’m wondering if it would make sense to modify that board more. I see there is a decent demand for it. If people are not in a hurry it might make sense to modify it could act as a bus master like the old style IMSAI/Altair accepting DMA etc. This would require adding a true data bus in and out lines, 2MH clock etc. so it could actually be used with other S100 cards in the bus.

I (or others), could take a stab at this, but it probably would be best to do a prototype board first.

Comments welcome.

John

John Monahan Ph.D

e-mail: mon...@vitasoft.org

Text: mon...@txt.att.net

From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Richard Cini
Sent: Wednesday, August 07, 2013 5:29 AM
To: S100-Post
Subject: Re: [N8VEM-S100:1757] IMSAI 8080 CPU card replacement

Yes, we definitely need those connectors.

Rich

Rich Cini

Collector of Classic Computers

Build Master and lead engineer, Altair32 Emulator

http://www.classiccmp.org/cini

http://www.classiccmp.org/altair32

From: Tom Lafleur <laf...@lafleur.us>
Reply-To: S100-Post <n8vem...@googlegroups.com>
Date: Wednesday, August 7, 2013 2:00 AM
To: S100-Post <n8vem...@googlegroups.com>
Subject: Re: [N8VEM-S100:1755] IMSAI 8080 CPU card replacement

We need to have both Altair and Imsai front panel connector.... Same signals, different connector

i~~ _/) ~~~~ _/) ~~~~ _/) ~~~~ _/) ~~i

Tom Lafleur

(858) 759-9692

On Aug 6, 2013, at 8:05 PM, "Andrew Lynch" <LYN...@YAHOO.COM> wrote:

Hi Josh! Thanks! Sorry I dropped the ball on this board. Whoosh! Right over my head!

I’d like to get a prototype board made of this design. I’ve translated your schematic into KiCAD.

Would you please review this schematic and verify it follows your design.

Double check everything and send me the changes and/or corrections.

There are some really odd things about this board though… the data bus doesn’t actually connect to the S-100 bus data lines. Is that right?

Thanks and have a nice day!

Andrew Lynch

From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Crusty OMO
Sent: Monday, April 29, 2013 12:20 AM
To: n8vem...@googlegroups.com
Subject: [N8VEM-S100:1596] IMSAI 8080 CPU card replacement

Hi Andrew,

Just thought you would like to see what I've done on one of your prototyping boards.

It's a replacement CPU card for an IMSAI 8080. It uses an 8080A and has the 16 pin socket to connect to the Front Panel.
I put 64K of RAM on the same card and a PIC microcontroller to provide Serial I/O, Floppy Disk emulation on a 8Meg flash chip and a Boot strap program.
It can boot up into CP/M 1.4 all on the same card. I did this because many of the other cards of that era are flakey and I wanted to get the IMSAI 8080 computer at the PC Museum in Brantford, Ontario working.

If anyone wants the full schematic & firmware, just let me know where to upload it.

:)J
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<Printing S100_8080 CPU-sch.pdf>

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