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New S-100 Boards

This section of the web site contains a listing of new S-100 boards I and others have recently constructed.  Still utilizing the basic IEEE-696 S100 bus format, we are incorporating modern designs into these new boards.  The long term goal being to adapt most major microprocessor chips (and support IC''s) to the S-100 bus.   We have for example designed new master/slave S-100 boards with CPU's from the 6502, Z80, 8086, 80286 and 80386 family's, and the 68000 Motorola family. We will be continuing this approach all the way up to more advanced 32 bit CPU's like the 80486 CPU and CPU's like the Propeller and RISC/ARM chips.  This has been, and will continue to be, a multi-year project.  A core of enthusiastic people have got together to do this. This process has now being going on for a few years with the number of boards well into the 1000’s.

I must stress however this is a hobby based group of people (spread actually around the world these days). There is no central organization or person “in charge”.  I and a few others design and produce new S100 boards (at our own expense) and when done, typically do a “group purchase” of a new board.  These are bare boards which must then be stocked with chips etc.  Typically I provide basic build/testing instructions and if needed, basic software.   The major ones are listed in the table below.   In many cases updated versions of the boards were/are being made.  

It is unfortunately a bit difficult for new people to get started since many by now already have their basic starting boards. 
 However from time to time a new “run” of an old board is done.  This needs somebody to organize and arrange a run.  It is more trouble than you might think to organize.  The boards are usually made by a (Chinese) group call PCBcart.com for us.   The required board fabrication Gerber files are available at the bottom of each board’s description on this sites web page.

To get started and find out more a boards availability it is probably best you follow this forum

From time to time a "board run" is proposed by a member.  Later when you are more experienced, you could start one yourself.

Also a few long term users mentain a stock of some of our most popular boards. They are listed here (along with a numberof other "ReteroBrew Computer" boards).  Please see here:-

https://www.retrobrewcomputers.org/doku.php?id=board inventory

for a list of boards available.

Alternatively you can get started quickly by scanning eBay for S100 bus motherboards, computer systems or S100 bus boards themselves. 

Here is a good place to start:-


Index Table Of New S-100 Boards  
As new additional prototype and final S-100 boards are made they will be documented here:-
Index To Hardware & Software Pages For New S-100 System Boards
  S-100 Board Debugging for Beginners.
  Basic S-100 Box, Comments about the Board Cage and Motherboard
  Power Supply
  S100 Motherboard
  S-100 IDE interface board for IDE hard disks and Compact Flash Boards
  IBM PC keyboard to ASCII Converter S100 Board
  4 Megabyte S-100 Static RAM Board
  S-100 Bus System Monitor Board
  Interrupt Controller and Clock/Calendar Board
  S-100 Bus Extender Board
  S-100 Prototype Board
  Serial I/O Board (with Speech Chip Synthesis and USB Port)
  Z80 Master CPU Board
  ZFDC Board (A Z80 based FDC board utilizing the Western Digital 2793)
  Propeller Driven Console IO board.
  Floppy Disk Drive Unit
  8086 CPU Board
  MSDOS Support Board
  VGA Video Board
  8088  Master/Slave  CPU Board
  80286 CPU Board
  6502 Master/Slave CPU Board
  LAVA-10 SVAG Video Board
  80386 CPU Board
  8 MB Static RAM OTT board (for 80386 Board)
  32 MB Static RAM OTT board (for 80386 Board)
68000/68010  CPU Board
  S100 Bus Terminator & Prototype Board
  MSX Compatible VDP Video Board
  IBM-AT ISA bus to S-100 bus converter board
  Parallel Ports I/O Board
  RAM+ROM Board
  V2 - Version of Z80 CPU Board
  16MB Static RAM Board
  V2 - Version of MS-DOS Support Board
  V2 - Version of System Monitor Board
  V2 - Version of 80286 Board
  8080A  CPU Board
  V3 - 16MB Static RAM Board
  V3 - SMB Board
  V3 - Dual IDE Board
  V2 - 80386 CPU Board
  V2 - 32MB OTT Static RAM Board
  V3 - MSDOS Support Board
  V6 - 16MB Static RAM Board
  Front Panel S100 Bus Board
  Z80 SBC Board
  MEM8 Plus Board
  OPL3/Game/Serial Board
  80486 CPU Board
  16 Bit VGA Board
  V3 OTT 32/64 MB Static RAM Board
  Dazzler II Video Board
  V3 OTT 8 MB Static RAM Board
  16 Bit Trident VGA Board
  Edison CPU Board
  Edison II CPU Board
  PDP-11 CPU Board

Tom Lafleur has kindly put together an Excel spread sheet list of components for a number of the above boards.
For some of the more recent boards Rick Bromagem has supplied the BOM list at the bottom of each web page.
It can be seen here.

By way of showing the evolution of these boards, I will describe my own S-100 IEEE-969 system.  This is a completely "homebrew system". Originally built in the early 1980's utilizing many of the S-100 boards of that era.  As I add new S-100 boards, I will go into some detail in an effort to help others build similar systems or allow them revive S-100 systems they may have stored away or have recently acquired. 

While none of this is rocket science, it does require some degree of electronic knowledge, familiarity with the S-100 bus and for the software, a working knowledge of CP/M, CP/M86 and MS-DOS (Programs, BIOS & Drivers) .  If you wish to become more informed about the S-100 bus itself try and get your hands of the book "Interfacing to the S-100/IEEE696 Microprocessors" by Sol Libes & Mark Garetz.  This book is commonly regarded as the "bible" for this field.

This will be a long term "work in progress" report. The index table above will direct you to new S-100 boards built or being tested.   See each boards section for more details.

Readers such as yourself are encouraged to participate either directly by contacting me via e-mail (substitute the AT for @), or better,  via one of the S100 related  forums.  

Here was my starting point for a S-100 system built with boards from the 80's. With this as a basis over time, we will swap out many of these boards into new more exciting and efficient boards using more modern IC's.

My Box With Arrows

My System Arrows2

My System 2013


  My System 2014
My S-100 System (As of April 2014)

  MY SYSTEM 2016
  My System 2016 

Getting Started in KiCad.
All our boards are designed using KiCad.  This is an open-source software tool for the creation of electronic schematic diagrams and PCB artwork. This is a fairly complex program to learn and will typically need weeks of practice to build up a board.  After the board circuit is generated with KiCAD it must then have all the chips arranged on the board and connected with 100's if not over a 1000 traces and vias.   This is done with another program called Freerouter.  Finally the resulting Freerouter files must be converted to Gerber files for the factory to actually fabricated the board.    For most of our boards I provide the most recent Gerber & Drill files to have a board fabricated. You may use these files -- at your own risk -- to have any board on this site made for non-commercial use.

KiCAD is an open-source software tool for the creation of electronic schematic diagrams and PCB artwork. Beneath its singular surface, KiCad incorporates an elegant ensemble of the following standalone software tools:-

    KiCad project manager
    EESchema schematic editor
    CVpcb footprint selector
    PCBnew circuit board layout editor
    GerbView Gerber viewer
    Bitmap2Component component maker

KiCad can be considered mature enough to be used for the successful development and maintenance of complex electronic boards. KiCad does not present any board-size limitation and it can easily handle up to 16 copper layers and up to 12 technical layers. KiCad can create all the files necessary for building printed boards, Gerber files for photo-plotters, drilling files, component location files and a lot more.

Despite its similarities with other PCB software tools, KiCad is characterized by an interesting work-flow in which schematic components and footprints are actually two separate entities. This is often the subject of discussion on Internet forums.

The KiCad work-flow is comprised of two main tasks: making the schematic and laying out the board. Both a components library and a footprints library are necessary for these two tasks. KiCad has plenty of both. Just in case that is not enough, KiCad also has the tools necessary to make new ones.
  KiCad Diagram

The main KiCad web site can be seen here. From there you can obtain excellent instructions, videos and examples as to how to lay out printed circuit boards.  However be aware to layout complex printed circuit boards like we have here needs many hours of experience and should not be taken on lightly

To get started please review the following files:-

Please note, recently (Dec 2015), a newer version of KiCAD has been placed in the public domain.  Unfortunately some of the files for the previous version of KiCAD (the above 2013 version) are no longer compatible with this version. They can be converted, but for now I will stick with the 2013 format. All our current files should work with that version.  It is way more than adequate for all our needs.

  Ki CAD buttons 
Initially you use the eeschema button to draw your schematic.  This is by far the most time consuming and hardest part of the program.  As I said above it takes many long hours to master this part.   You then need to convert this schematic to an actual board layout with all the IC's etc. physically in place.  

From your schematic you make a .net file

You then call in the second program cvpcb that uses the .net file to assign each IC in your schematic an actual board "footprint".  Most common footprints are already available as .mod files that come with the many KICAD "libraries".  Cvpcb generates a .cmp with all the boards components footprints.

You then use the program pcbnew to do the actual board layout. It utilizes all the .net and .cmp file data to layout your board. All the traces are shown initially as lines connecting IC pins to IC pins. Pcbnew generates a board layout file with a  .kicad_brd extension.  (Note older version of KiCAD used a .brd file extension. This is no longer supported).

Also included (see bottom of this page) is a collection of S100 footprint files specific for our S100 boards.  Make sure when you setup KiCAD that these files are on the default file search paths for these programs.  (Set Preferences, Library, User defined search path....  for eeschema, cvpcb and pcbnew).

For small simple boards you can move/edit etc. these lines by hand.  For complex S100 boards like we have here however, it is really necessary to use a trace layout program called Freerouter.  The windows .exe program can be downloaded from here.  It is completely self contained and should run in any folder on your system. 

You feed it a .dsn file (generated with pcbnew using the file menu "Export" command).  It returns a .ses file which is reaccepted by pcbnew.  See the above diagram. Rout optimization for complex S100 boards like these is a slow process. Complex boards can takes days.  You can watch the number of "vias" decrease, and the overall length of all the boards traces decrease over time.  When you see no further improvement its time to stop.   The critical file we want in the end is the pcbnew generated .kicad_brd file with the optimized board traces supplied by freerouter. That file is then used by the pcbnew "Plot" command to generate the boards "Gerber files". These files are required by board manufactures to fabricate your board.

This site (at the bottom of each boards description page) has the required .kicad_brd file you need to generate the Gerber and drill hole files for manufacturing our boards.

Using S100Computer KiCAD files
All S100computers S100 boards now have a Gerber .zip file at the bottom of each boards page. If you wish to use these files for your own run its easiest if you use only this .zip file.    If you do your own layout, I suggest the following approach:-

When you “Plot” the files in KiCAD place them in an empty/new sub-folder (Gerber).  Then go to that folder and combine them all into one .zip file.  This is the file you send to the board manufacture.  In that folder the should be a total of 12 files including the zip file.  Always, no exception.  If less, go back to the “plot” dialog and find out what file is missing.  (This assumes you will not have a silkscreen on the back of the board).
One quirk of freerouter is that sometimes it places vias between the gold edge connectors.  I largely mitigate this by placing a protected/keep-out area on the bottom ¼ of the connectors.  See this picture:-
  S100 Connector-Freerouter
It must be less than half the height of the connector pads.  Even then,  after the board is resolved, occasionally you will have to hand tweak some vias by moving them upwards.  I also like to when possible, avoid traces running near the tops of the gold pads by pushing them up. 

While on this, in general before I send a board to freerouter I hand lay down some wide major power lines.  When a board is done I tweak things like moving around an Vcc traces that are on 3 sides of a pad/via away slightly. Highlighting the Vcc traces and running extra traces (if possible) to the power pins of the major power hungry chips like a 1508 CPLD.   This often requires shifting freerouter traces and using multiple vias.  So in many case the final Gurber file will NOT be the same as the original Freerouter/KiCAD "Plot" files.
Finally before you save the Gerber plot files be sure to do a “design check”.  On a few occasions, (~3 times for probably 1000 runs), freerouter had a via too close to a trace.
So if you wish to use these S100Computers files for your own run, use only the .zip Gerber file at the bottom of each boards page.  If you “roll your own”  you need to go through the above steps.  The .zip files are all you need to send to most board fabricators.

Lastly one trick, before you import the freerouter .ses file back into KiCAD save the .kicad_pcb file with another name such as xxx(no traces).kicad_pcb.  That way if you wish to modify the board you will not have to remove all the freerouter traces (KiCAD removes your own hand drawn traces as well).

S100 Board Manufactures.

Almost any printed circuit board manufacture can fabricate these relatively simple two sided printed circuit boards. Issues are cost, time and what their setup/minimum order is. Highly recommended for production boards (with gold plated fingers etc.) is PCBcart.com and for prototype boards  4pcb.com.  The latter have a $33 deal per board if you order 4 or more boards. However unfortunately they don't supply gold plated edge connectors at this price.  For such final production boards PCBcart is the best.
  PCB MFgs


Parts Lists.
Most of the boards on this site use common 74LSxx style chips.  If you are going to build a number of S100 boards (or repair them),  you really should build up a stash of these chips.  I get most of my components from Jameco, Mouser, Anchor-Electronics, Unicorn Electronics or for discontinued chips UTSource, and in that order.  I use Jameco for all the support stuff, sockets, jumpers etc.    I wish I had time to write-up a detailed BOM for each board, fortunately Richard Chin and Rick Bingham have done so for some boards - thanks Richard & Rick.  If you want to contribute please send one on to me.

KiCAD Download (Note this is a large file, 197MB).
KiCAD Folder of default KiCAD and S100Computers Footprints etc. (Note this is a large file, 32MB).
Freerouter Download
Advanced Circuits Prototype Boards site
PCB Cart Commercial Boards site


This page was last modified on 07/02/2017