This is ROM based Zapple like monitor program for a Z80.  It is a menu driven ROM based program to allow you to bring up a basic functional system. It is toughly documented to allow its adaption to most hardware configurations.
 

This is a diagnostic program for a Versafloppy II disk controller board.  Again it is menu driven to allow you to bring up a basic functional system.

Please click Versafloppy II Diagnostic Program for more information.


SIO8.Z80
A Diagnostic Program for the SD Systems Serial IO/Clock Board.
This is a very powerful 8 Port Serial (RS232) I/O board. See here for a detailed description.
I have written a little program to configure the Serial Ports and Time/Clock chip on this board.
It can be see here, and downloaded here.  As usual it can be easily modified for the same chip on other boards.
  
Besides containing four Zilog 8530 dual serial I/O chips, this board also has a National Semiconductor MM58167 Clock/Calendar chip. The above program also allows the on board clock chip to be set and read. However for the S100Cpmputers  custom built PIC/RTC board (which also utilizes the MM58167), see below, has a more extensive and detailed program. That program will also work with this board BTW.


PCGET.ASM and  PCPUT.ASM  
Moving Files Back & Forth Between S-100 Computers and an IBM PC.
Often it is nice to be able to move a CP/M or other S-100 based programs (Monitor, diagnostics etc.) up to a PC. There it can be used as a backup storage area or assembled/run on a PC based Z80/CPM simulator. To do this one needs a way to conveniently get data back and forth. You could use a 5" floppy (on an old PC) and configure the S-100 system to read the disk, or use one of the older PC disk format reading programs and go in the other direction.

I opted for a simpler approach. I modified one of the many versions of Ward Christenson's CP/M's  "Modem Program" to simply pass files back and forth over a serial link. I use a USB->Serial connector on the PC and the SD Systems IO8 Serial board on the S-100 end. (With slight modifications any serial board can be used). The original program is stripped down to simply accept (or send) a file named in the CP/M command line.   These programs can be assembled to utilize the serial ports of the SD-Systems Serial IO board or the S100Computers Serial-IO Board. It can be easily modified for most other serial ports.
 

Both of these programs should be assembled with Digital Research's MAC assembler.  This program can be obtained here.

The Zip file of both programs can be obtained here.

If you are up to it, you can use the CP/M program "LU" to compress many CP/M files into one large file, upload that "library" file and extract files out on the PC side (using a CP/M simulator).  LU.COM can be obtained here.

On the PC end one can use any number of PC based serial port Modem programs. They should be capable of utilizing the original "XModem" protocol, not the newer "XModem (crc)" or "XModem (1K)" protocols.  I particularly like Celestial Software's  Absolute Telnet program. They have a free "light version" and a "Professional version" for $50. The latter is well worth it as it has many other additional useful features.


ALTAIR.COM
Running CPM3 on a PC
In much of my development work for building CPM programs for my S-100 system I actually build, edit, assemble and sometimes even execute the program first on an IBM PC  using Windows XP, 7, 10 etc.  One day I hope to have an S-100 video board of the resolution that current PC video boards have but for now, nothing compares with the editing convenience of Microsoft's Visual Studio when working with .Z80 or .ASM files.
 

While you can edit the programs under windows (Visual Studio), you need a "CPM emulator" to assemble them and/or execute them.  There are a few good CPM emulators for the PC available.  I like to work with Peter Schorn's AltairZ80 Simulator. He has put an enormous amount of work into building a Windows based program that behaves as if your PC was a S-100 Altair computer.  Start with this documentation for some background information.  However to assemble and run your own CPM programs you only need to launch the CPM3 emulator within the Altair.com program itself. From then on (transparent to you) you are operating under CPM3 in a Windows box. The necessary software and instructions are all described here.


Software for the  S100Computers IDE Drive/CFCard Board
I have constructed an S-100 board that allows one to interface an IDE hard drive (or memory board) to the S-100 bus.  Relative to the old ST-506 Winchester drives, IDE drives are simple to interface, quiet, and inexpensive.  All the software for that board can be found here.
 
 
Please click An S-100 IDE Hard Disk Controller Board  for more information.
 
 
Software for the S100Computers PIC & RTC S-100 Board
The PIC and RTC S-100  Board  I have constructed with its Priority Interrupt and Real Time Clock S-100 board that allows one to utilize the interrupt structure of the S-100 bus with both 8 and 16 bit CPU's.  The board also contains a National Semiconductor MM58167 Clock/Calendar chip.  This is really two S-100 boards in one.  Example software for interrupt testing can be seen here, and downloaded here.   Software for the RTC chip and checking its functionality worth CPM3's date and time stamping capability can be downloaded here.
 


PCLOAD.ASM
Moving Files From a PC to an S100 System anywhere in its address space from 1K to 1M
In developing software for 8088, 8086, 80286 and 80386 S100 systems it is often necessary to load software above a Z80's 64K address space.  For example the 8086 monitor resides at F000:8000H.    This is particularly handy when you are first developing hardware/software. (BTW, the most recent versions of these '86 monitors have an internal command, ("W"),  to do what we have below for you).  Such a file transfer process allows you to utilize programs like Visual Studio and NASM to write your programs on the PC and quickly test the results in your S-100 system.

I have written a short simple version of the above PCGET to directly load the code (.bin, .com etc.) from a PC directly into the S-100 memory space. It is a small CPM based program called PCLOAD.COM.   The program asks for a Load address. This can be any 1K boundary from 1K-64K.  If however you have our S100Computers Z80 CPU board, it utilizes the "Memory Window" on that board and can load the code anywhere from 1K up to 1M.
   

The program to download from a PC a file to a CP/M system is PCLOAD.COM. The source can be seen here.
The programs can be assembled with Digital Research's MAC assembler.  This program can be obtained here.

XMODEM
Moving Files From one PC to another.
The CPM program "XModem" is a well known program used to conveniently move CPM files from one computer to another over a serial (or modem) link.  Many versions of this program can be found on the web.  Unfortunately some have bugs that appear when large programs are transferred. The version here has been cleaned up by Bob Bell and can now also be downloaded from this site.

XModem.zip


A Collection of CPM based 8080/Z80/8086 Assemblers and Linkers.
Over the years I utilized a number of assemblers and linkers. Each had its own advantage and quirks.  I have put together a collection of some of the better ones in one spot for easy downloads.  They include the following (in no particular order) ....

TDL's Z80 Macro Assembler.
Cromemco's Z80 Assembler.
Digital Research's MAC and RMAC
SLR's ZASM
Digital Research's ASM86
Microsoft's M80 and L80
SD Systems ZASM
8086 Assemblers
68K Assembler
6502 Assembler
Z80 T0 8080 Translator
Others.

They are all briefly discussed and can be downloaded here


A Collection of Useful Assembly Language Routines
Check here for a collection of small but useful Z80, 8080 and 8086 Assembly Language routines I use time and time again in programs.


A Collection of all Digital Research Software
Check here for a collection of all Digital Research Software, Source code and Manuals.  An amazing collection!


Bringing Up CPM3 for the First Time
Writing a CPM3 BIOS for the S-100 ZFDC FDC Board
Most early S-100 Computer systems used CPM2.2 (or earlier) as the basic computer disk operating system.  The system was fairly simple to implement and was the germination base for much of the microcomputer worlds software.  The system however had many limitations in particular it was designed for a standard 8" IBM single density single sided floppy disk with 128 byte sectors.  As newer disk sizes and formats started to appear -- particularly hard disks, the system started to show its limitations.  Digital Research's answer was CPM3.  This version of CPM allowed essentially any sector size and disk format to be used easily and efficiently.  What CPM3 did was hide within the operation system itself the 128 byte sector size requirement and allow the BIOS to work easily with any sector size "transparently". The system had an  elaborate disk hashing/data buffering system as well.  Of particular usefulness was the fact that it existed in two forms. A "standard" NON BANKED version that operated like CPM2.2 in a Z80 system with 64K (or less) of RAM.

However there was a much more efficient "BANKED" version of CPM3 which by using onboard 'bank switching" hardware, could utilize up to (in theory) many megabytes of RAM. Typically 128K or 256K RAM systems were used.   This allowed for a very fast and sophisticated system with for example things like file time and date stamping. 

It should be noted that this BANKED system absolutely requires that the Z80 can switch in and out a portion of its 64K adders space with other RAM boards.  There were a number of ways this was done in hardware.  The Cromemco and Godbout systems utilized an IO port to switch RAM boards.  Intersystem's and our own S100Computes Z80 board, use on-board Z80 CPU board hardware to extend the addressing range of the Z80.  We will discuss this later.

For now lets start with a very simple CPM3 BIOS.  We will step by step build the system up to a much more complex setup. Eventually arriving at a BANKED system with multiple floppy, hard and memory disk connections.  
Please click here to read about this process.


Bringing Up CPM3 for the First Time
Writing a CPM3 BIOS for an S-100 IDE Hard Disk or CF Card
This section is an extension of the above CPM3 for a floppy disk except that now we will boot CPM3 up from a Hard Disk
Please click here to read about this process.


Bringing Up CPM86+ for the First Time
Writing a CPM86+ BIOS for the Dual S-100 IDE and ZFDC Boards
This section is devoted to beginners trying to implement CPM86+ in their S-100 system.  Obviously the system must have an 8686 (or above) CPU board.   The details and examples given are quite general and can be applied to any capable S-100 system. However all the examples are centered around our Dual IDE and ZFDC disk controllers.
Please click here to read about this process.


CPM, MSDOS etc. CF Card Images
Please click here to go to the page to copy various CPM3 and MSDOS CF card images to CF cards.

8086.A86
An 8086 System PROM Monitor
This is a ROM based Zapple  like monitor program for an 8086 based system.  It is a menu driven program to allow you to bring up a basic functional system. It is toughly documented to allow its adaption to most hardware configurations. 
The monitor contains three separate sections:-

1.    A basic monitor like the MASTER.Z80 one described above.
2.    A diagnostic section to run the IDE board with an 8086
3.    A modified version of the IBM-PC/AT BIOS that allows you to run MSDOS (V5.01) unaltered.
   
    
Please click 8086 Monitor for more information.
 


68000.X68
A 68000 System PROM Monitor
This is a simple ROM based Zapple like monitor program for an Motorola 68000 based system.  It is a menu driven ROM based program to allow you to bring up a basic functional system. It is documented to allow its adaption to most hardware configurations.
       
Please click 68000 Monitor for more information.

 
65MON.ASM
A 6502 System PROM Monitor
This is a simple ROM based Zapple like monitor program for a simple 6502 based system.  It is a menu driven ROM based program to allow you to bring up a basic functional monitor on the S-100 bus. It is documented to allow its adaption to most hardware configurations.
       
Please click 6502 Monitor for more information.


80386.A86
A 80386 System PROM Monitor
This is a ROM based 80386 monitor evolving from the above 8086 based monitor.  It is a menu driven based program to allow you to bring up a basic 80386 functional system. It is toughly documented to allow its adaption to most hardware configurations.  The monitor also allows one to exercise the complex "Protect Mode" 32 bit features of the 80386 with its sophisticated memory management and interrupt features. The monitor contains four separate sections:-

1.    A basic Real Mode monitor like the 8086 one described above.
2.    A diagnostic section to run the IDE board with an 80386 (Real Mode).
3.    A modified version of the IBM-PC/AT BIOS that allows you to run MSDOS (V5.01) unaltered (Real Mode).
4.    Protect Mode/32 bit mode with basic monitor commands, interrupts debugging/single stepping etc.
         
Please click 80386 Monitor for more information.

8080.ASM
An 8080 monitor
This is ROM based Zapple like monitor program for the 8080 CPU board.  It is a menu driven ROM based program to allow you to bring up a basic functional system. It is documented to allow its adaption to most hardware configurations.
 
    
Please click 8080 Monitor Program  for more information.



PDP_MON
A PDP-11 monitor
This is ROM based Zapple like monitor program for the PDP-11 CPU board.  It is a menu driven ROM based program to allow you to bring up a basic functional system. It is documented to allow its adaption to most hardware configurations.
 
    
Please click PDP-11 CPU Monitor for more information.


Bringing Up MSDOS for the First Time
This section is devoted to beginners who want to implement MSDOS in their S-100 system.  Obviously the system must have an 8686 (or above) CPU board.   The details and examples given are quite general and can be applied to any capable S-100 system. However all the examples are centered around our Dual IDE and ZFDC disk controllers.
Please click here to read about this process.


Serial Communications Program (SCP) V2.0 Community Release.
This software was written entirely by Bob Bell.  Bob is well known to our community.  If you have any questions about the software you should contact him directly. He has submitted the following summary:-

Attached below is the version 2.0 Community Release of my new/old Serial Communications Program.  After over 17 years of on-again, off-again work, this is finally in a state where I can release it for public consumption.  The zip includes three files: A readme for a brief explanation of program operation, an assembled and ready to run .com file and the source code in Z80 assembler.  My apologies to those running 8080/85 CPUs.  There were parts of this program that would have been very difficult without the additional facilities of the Z80.  For those in need of a communications program, albeit XMODEM only, I recommend Martin Eberhard's excellent XMODEM program.

The catalyst for this program came in the late 1990s when I came to the realization that my 8" and 5 1/4" floppy disks were not going to last forever.  I had already lost some files due to magnetic and physical damage (fortunately, retrieved from backups), and I concluded that the best way to protect against further loss was to create an easy means of transferring data between my CP/M machine and any one of my Windows (or, at the time, old DOS machines), where hard drives are more reliable, and easier to backup.  It was not difficult to get 22NICE operating to transfer files by floppy, but the only format I had in common was 5 1/4" where I had a total capacity on the disk of 184K.  This proved difficult and time-consuming, so I set out to create a more automated means of transferring files without the file size limitation.  Here is where SCP began.  I had very limited knowledge of communications protocols and thought that XMODEM was for making computers speak to mainframes over a modem.  SCP version 1 was very primitive, but worked...s l o w l y.  There I got stuck, because I could not get enough speed to satisfy my needs.  The program went on the back-burner and I moved on to other things.  Then about 2012 I discovered this group and learned that I was not the only guy in the world trying to keep an S100 machine afloat, and my interests in reviving my old "save the disks" project was rekindled.  The rest is documented in the Revision History of the Source file and here it is, now, the culmination of countless hours of work, SCP version 2.0.

Please give it a try on your Z80 machine. Feedback is welcome through this forum or direct to my email address, shown in the source file.  There are some known bugs, omissions and limitations documented at the beginning of the source file.  I hope they don't cause you any operational difficulties.

Although I have copyrighted this program, I do hereby grant permission for anyone on this forum to use the program at no cost, and share it with anyone else who can use it.  If you make modifications to the program, please let me know what the changes are, so I can incorporate them into the original.  If you use any major parts of the program in other programs you write, recognition for the code I wrote would be appreciated.

Bob Bell

Please click here to download the SCP.zip file containing the program


68030.X68
A 68030 Monitor
This is ROM based Zapple like monitor program for the 68030 CPU board.  It is a menu driven ROM based program to allow you to bring up a basic functional system. It is documented to allow its adaption to most hardware configurations.
       
Please click here for the 68030 Monitor Text File listing and here for the 68030 Monitor.ZIP files.

PDP11 Progarms
This is a page that will contain a growing list of small PDP11 programs suitable to run with our PDP11 CPU board.
Please click here.   


Bringing Up CPM68K for the First Time
Bringing up CPM68K (using a 68000, 68010 or 68030 S-100 Board) can be a somewhat daunting task for beginners.  Not only is the hardware different and you have to worry about its (often untested) functionality, but the software is an order of magnitude more complex.  Please see here for more information



FPGA_DC Board Software
This page contains programs related to the three FPGA_DC Disk Controller Boards.  To make any sense you must be familiar with that series of boards before going further.
Please click here.

This page was last modified on 08/09/2023