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RE: [N8VEM-S100:811] S-100 Prototyping Board

Hi Don!  Thanks!  Last year Neil sent me a design for a similar board.  Please see the attached message.  This project is on the back burner awaiting resolution of the current boards in work.

I'd like to make similar board with the main purpose of helping hobbyists make a minimal booting system.  Basically a CPU board with another simple board with minimal SRAM, boot ROM, and IO enough to get the system going into a debug monitor.

Thanks and have a nice day!

Andrew Lynch

> -----Original Message-----
> From: n8vem...@googlegroups.com [mailto:n8vem-
> s1...@googlegroups.com] On Behalf Of Don Caprio
> Sent: Monday, May 14, 2012 10:58 AM
> To: n8vem...@googlegroups.com
> Subject: Re: [N8VEM-S100:811] S-100 Prototyping Board
> I was hoping for a similar board(s) for my IMSAI as well.
> I have a schematic which is almost complete that uses minimal components.
> Actually Earl Goodrich helped with the design and I know he would be willing
> in helping complete the design. He also working up a design that would go on
> the
> S-100 buffered
> prototype board.
>   I have a KiCad version of the schematic nearly complete but is lacking the
> static ram foot print.
> My plan was to spin up a PCB prototype.
>   It's designed around only two 32Kx8 DIP's which are available from DigiKey.
> So with only a couple static ram chips needed and some additional support
> logic I believe this board could be simple and inexpensive to produce.
> I'm game for starting a new project on N8VEM pbworks if there is enough
> interest.
> On 05/13/12 08:41 AM, litte...@mchsi.com wrote:
> > Josh,
> >
> > I also have a few IMSAI's that are in need of
> > a reliable memory.  Old memory cards with a high
> > chip count of obsolete, hard to find and a bit
> > expensive memory chips.  Plus the possibility
> > of flaky sockets.
> >
> > My plan is to build a simple 64k memory card with
> > minimal components using the buffered prototype
> > card.  I would like the card to either start out
> > at 0000h or 2000h (for NorthStar DOS), ability
> > to do deposits from the front panel and maybe a
> > EPROM at the top end of memory.
> >
> > I have a few ideas using some circuits from Andrew's
> > other boards and examples I've seen in some older
> > S100 books.  Right now it's just on paper.
> >
> > Would you be willing to share your design ?
> >
> > Todd
> >
> >
> > ----- Original Message -----
> > From: "Crusty OMO"<crus...@hotmail.com>
> > To: n8vem...@googlegroups.com
> > Sent: Saturday, May 12, 2012 10:10:41 PM GMT -06:00 Central America
> > Subject: [N8VEM-S100:809] S-100 Prototyping Board
> >
> >
> > Hi Andrew,
> >
> > A few months ago I bought the prototyping board from you.  Naturally, you
> wanted to know how I would be using it.  I can't blame you, since my
> curiousity is the same and I share the same love of electronics.
> >
> > I bought an IMSAI back in November.  I was thinking of using the prototype
> board for either remote controlling the IMSAI, or to simulate a floppy drive
> system using an SD card.  But I am more interested in restoring this old IMSAI
> to using it's existing S-100 cards.
> > But those S-100 cards were driving me crazy.  I needed some firm ground
> from which to trouble shoot.  I was even starting to doubt my RAM cards,
> well, I even seen the DRAM cards do strange things when running with the
> Floppy Drive controller's BOOT ROM.
> >
> > So, I used your card to create a 32K RAM + 32K EPROM card.  This way, I can
> write some code and have a working system, then slowly introduce the other
> cards, etc.  It's not very interesting, but it's proven to be quite helpful.  I
> already located a weird problem with my SIO card that I never knew existed.
> >
> > When I am finished restoring my IMSAI, I will repurpose the card as a stand
> alone operating system for another IMSAI located at the Personal Computer
> Museum in Brantford Ontario, Canada.  I'll write up some demo code to flash
> the lights, or play some game on a dumb terminal.
> > This way, they can have their computer running.  Without some software,
> the IMSAI might as well be a bunch of LED's wired to some Switches.  ie not
> very interesting.  I might even add more memory and find the way to bank
> switch, but I'm far from this goal to say for sure.
> >
> > Cheers! and Thanks for a great head and help on my project machine.
> > Josh
> >
> > PS. Feedback on the board.  It would have been nice if there were traces
> that could "Almost" connect the Data IN and OUT busses.  Almost being just
> eight short jumpers away (.1" per data line).
> >
> >
> >
> >
> --
> Don Caprio
> ilv...@gmail.com

--- Begin Message ---

One more thing, in 2010 I designed and wire wrapped an S-100 card that does the following, I use it with a Wameco 8080 CPU card / Tarbell Single Density controller in my CP/M 1.4 system.


64K RAM – ability to enable/disable the RAM in 4K blocks (you can leave 4K holes in the RAM space for things like memory mapped video cards (VDM1) and boot/monitor EPROMs.

2xPIO (8255s)

2xSIO (8251s)

AY-5-8116 Dual BAUD Rate generator

I have a serial “3M” brand Keyboard from the early 80s (early video editing system keyboard), I custom modified it to work with one of the UARTs in my design, this is on card.

Centronics Parallel port using an 8255 (I never got this fully working)

CP/M 1.4 configs


Note sure if the attached PDF has any interest in old school design (I did use a few modern parts such as 32x8 SRAMS and a MAX232), I could provide pictures as well.


I also have a set of scans of another I/O card designed by Big Dave (http://ztac.net/ - Know for FBE Research (Heathkit add on cards) back in the day) in the late 70s, I also have the wire wrapped card he wrapped from the design and have used it, in my mind this is a truly interesting artifact as the comes from the time when S-100 was state of the art. Would pics and the scans be of any historical interest.





From: Andrew Lynch [mailto:andrew-lynch@sbcglobal.net]
Sent: Sunday, April 17, 2011 9:37 AM
To: 'Neil Breeden'
Subject: RE: S-100 Cards


Hi Neil!  Thanks!  Sorry I am all out of the S-100 Z80 CPU boards.  My plan is to do a PCB reorder later this spring.  Would you like me to add you to the waiting list?


I will be making an order for the S-100 Console IO boards soon -- probably this weekend actually!  I can add you to the waiting list if you would like.  Please let me know!

The S-100 Console IO has been redesigned to use a single Propeller and is now basically a “terminal on a board”.  You plug in the VGA monitor and PS/2 keyboard, configure and go.  All the other IO features have been moved to another board we are working on for later.


I hope all is well with you and your family.  These are stressful times and I wish you the best!

Thanks and have a nice day!

Andrew Lynch


From: Neil Breeden [mailto:nbreeden2@comcast.net]
Sent: Saturday, April 16, 2011 2:04 PM
To: 'Andrew Lynch'
Subject: S-100 Cards




   I was just going over the S-100 cards I have bought and realized I still need to get an “An S100 Z80 Master CPU Board” and a “A Dual Propeller Driven Console IO board.


  Do you have any in stock? Ideally I’d take two CPU cards and one Dual Prop card.


  Hopefully someday I will have time to assemble a system using them all.



Attachment: NEILB_Memory_IO_Card.pdf
Description: Adobe PDF document

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