Z-80 Space-Time Productions Single Board Computer

Technical Support Information

Introduction

This site is technical repository for information related to the
Space-Time Productions Z-80 single board computer, "Master Controller Board", which were dated April 20, 1982 © M.Simon.

Somewhere between 75 and 100 of these boards were sold on Ebay between 2001 and 2005, both as bare pcb's and as "Kits", complete with a full complement of necessary IC's and component parts to get started.

The Mission of this web site is to be a forum to pass information related to this board and Z-80 programming and applications in general to the community of people who own it. Feel free to use any information provided, I am also interested in posting any programs or information you wish to share.
Plus, it's just great fun!

If you wish to donate information, source code, or photos for use on this site, it will be credited to you along with my sincerest thanks.

Other hobbyists who use different Z-80 based computers have also dropped by looking for information or have donated ideas and info.
So welcome, everyone! Please feel free to email, it's always good to hear from fellow enthusiasts.


I explain everything in excessive detail, so be prepared to do some reading...
~Joel

There are 10 types of people in the world: Those who understand binary and those who don't.

The Kit

The kit with IC's as seen on Ebay
The kit with main IC's, as seen in the past on Ebay

The chipset, connectors, and parts
The full-blown chipset, parts bag containing some "R's and C's" and connectors.
This particular sale came complete with the 74xx logic gates, and was a good buy for some lucky bidder.

These kits were sold by Ron Weiss Electronics; his Ebay identification is networkrw if you wish to contact him.
The kit contained:

  • CPU pcb
  • A/D pcb
  • Serial port-B expansion pcb
  • Monitor Rom
  • Z-80 Microprocessor
  • Z-80 SIO-0
  • 8253 Programmable Timer
  • 8255 Programmable I/O (various quantities 1-3)
  • 8279 Keyboard/Display Controller (not on all kits)
  • Various components (not on all kits)

As of December 5, 2005 Mr. Weiss informs me that he has completely sold out of these boards, however he has a few bare Analog-to-Digital ADC0816 boards and RS-232 Second Serial Port boards remaining in his stock.

Just as there are probably infinite number of ideas and applications you can use this board for, there are also a number of ways you can configure it as well. It doesn't necessarily have to have all the Input/Output IC's and so forth. For instance, you may only need one PIO chip instead of three, and no keyboard/display interface, or maybe you only need 1K of ram to control something - it's entirely up to you to configure it how you need it.

There are a number of TTL gate IC's you will need for decoding, timing, and buffering. Refer to the schematic IC layout for a complete list of IC's, XTAL, resistors and capacitors also needed.

This is a really fun and versatile computer! Designed as an industrial controller, there is no CRT/video circuitry or mass storage interfaces. It does have RS-232 serial ports and a specialized Keyboard/Display adapter (8279) on board. It uses industry standard Intel P8255 I/O port chips so interfacing and control of the 'real world' is relatively easy.

Since this kit is supplied only as a pcb, you pretty much have the freedom to creatively enclose this computer any way you like. It was likely designed to be installed inside one or more pieces of pre-existing equipment.

My Space-Time Productions Z-80 SBC

My Z-80 Single Board Computer consists of:

  • The bare pcb board.
  • One each Z-80 microprocessor.
  • 2716 Monitor rom.
  • Three each 8255 PIO Programmable Input/Output IC's.
  • One each 8279 Keyboard/Display IC.
  • One each 8253 PIT(CTC) for baud rate generation.
  • One each Z-80 SIO-0.
  • Various TTL-LS logic IC's.
  • Four each 2114 Static Rams (removed since the Memory Expansion PCB).
  • Sockets for each IC (a rule of mine).
I have not been able to easily locate [nor do I need] the AMD 9513 5x16-bit counter IC, and the AMD 9511 Floating Point Mathbox IC. Thanks, but I really don't have any application which could use either one of them.

Expansions I Have Made To This Computer:

  • Discrete I/O Board: Utilizes 4 each ULN2803 50V 500mA open-collector output driver IC's. Eight drivers on each IC provides 32 total Discrete Output points. I use 2 each 1K-ohm x 8 resistor pull-up packs tied to the 5V supply off the board. This gives me 16 Discrete switch inputs, which are high (logic 1) when the switch is open. I currently use this board to drive 28V "discrete input and outputs" on Avionics panels at my work desk, makes a good test-bed.

  • Memory Expansion Board: Completed April 2005, this board added two 32K non-volatile static rams and capacity for 4 each 2732 roms. The memory is bank switched using jumper pins. The fourth Rom socket is jumper selectable to hold either a 6116 Static Ram or a 2732 4Kx8 Eprom.

  • HD44740 LCD Display 2 x 40: I have also tied this 2x40 ASCII character display in using the 9511/12 socket at IC-17.
    This is an LED-backlit device which uses a negative 2Volts for biasing. $6.00 from BG Micro.
    I have built a special timing circuit using a 74LS175 which allows me to:

    • Read and Write the HD44780 as a directly mapped standard I/O device
    • Provide the -2.0Vdc bias voltage for the glass
    • Display the data bytes to and from the LCD using latched LED's
    IC-17 was designed for the AMD9511/12 floating point Mathbox. Since they are obsolete and difficult to find, it was the ideal place for this LCD Interface board as it has WAIT-, CLK, AB0, DB0-7, CS-, and both +12 and +5 available, as well as spare pins for -12V. This interface works significantly better than tying the LCD onto 8255 PIO, and saves those pins for other purposes.

  • Monitor Rom: I have added various features and functions to the original Monitor program, as follows:

    • Rev 8.1
      • Jumps the baud rate up to 38,400 for the console Serial A [reqs new xtal].
      • Sets Serial B at 31,250 Baud for MIDI data.
      • Has ANSI color sequences for changing text color on-the-fly with Hyperterminal.
      • Initializes all devices on bootup, including the HD44780 LCD.
      • Generates ROM checksums on bootup.
      • Has a CP/M-like multi-device output print command.

    I have done some development for an 8K monitor program which uses the front panel and the 2x40 LCD display, rather than using an external terminal or PC computer running Hyperterminal. I only get to work on this once in a while, and so it is still pretty much in early stages.

  • MIDI Interface for Serial B port: See the menu for how I created an opto-isolated circuit for connecting MIDI devices. I have acquired a MOS 6581 CBM synthesizer IC [from the Commodore C64 computer], and am planning a music synthesis circuit board as a future add-in.

  • Front Panel: I was able to salvage about 36 professional LED-lighted switches and 9 green and 9 red indicators (which also look exactly like the switches) off of some old equipment. They are top-quality devices and would probably have cost me about $6.00USD each new. Had new 19" rack panel milled-out by a friend. Completed the interface PCB and am in the middle of code and test. The control gained by this will give some monitor functions without a host PC, and will primarily be to interact with the MIDI and 6251 SID music synthesizer IC. See the pics on the 8279 Panel page, I think you'll like it.

Resource Literature

These are two valuable books for use alongside your Space-Time Computer. The MCS-80 User's Manual cover takes several forms, here is an early one. You can usually find this one on Amazon. It's focus is on the 8080-8085, but there is a wealth of technical data sheets inside including the 2114 static ram, various proms, 8212 I/O port, a very in-depth data set on the 8255 PIO, 8251 UART and lots of good background info on RS232, 8253 PIT, and 8279. ISBN: 1555120091

The Z-80 book by Rodnay Zaks is a good resource for Z-80 Assembly/Machine Code, teaches a lot about the fundamentals and concepts of programming, a good instruction code breakdown (there are a few errors in the book, but easy enough to locate and correct), how to handle data in tables, binary math and a lot about the workings of the Z-80 signals. Also has execution times for each instruction based on a 2MHz clock (same as the Space-Time). Very handy. ISBN: 0895880695

These are both easily available from Amazon.com and Ebay.

Practical Applications

While I like to believe that the possibilities are just about boundless, let me just preface everything by saying that you have to be a hobbyist on the level of enjoying things that work down to the bit level and one who likes vintage technology to get the sense of fulfillment that I have from this project. It can be all-consuming, and you should be prepared to funnel some funds and plenty of hours of research and soldering into it.

Here are a few things the users have done:

  • Robotics One person combined the services of this board to an S-100 Z-80 board to control his life-size R2-D2 robot!
  • Model Railroads As a controller to animate, control motion and lighting based on where the train is in the layout.
  • Christmas Lights To send flashy sequences to light strings by way of Solid State Relays.
  • Process Control To control sequences on a machine based on position switch inputs (assembly line stuff).
  • Education Probably one of its strongest selling points, to teach Z-80 machine language, circuitry, I/O and the old BASIC computer language.

Here are some ideas that I have.
Some of these I've completed, others are in work or waiting in the wings:

  • BSA Pinewood Derby As a race controller to sequence the 'tree', pull in the car-blocking solenoids and to time the cars as well as determine the winner.
  • MIDI Filtering To take in canned MIDI files and filter out the Track 10 "Percussion" track before it hits the keyboard.
  • MIDI Instrument To read in switches or key-hits and convert them to a MIDI stream for driving keyboard or drum machine.
  • MIDI Light Controller To allow stage lights or special effects displays to be synchronized to music.
  • SID Synthesizer To drive the Commodore 64 "SID" chip and take MIDI data out to it.
  • Church Chimes There is a local church whose paper-roll-driven chime machine is long dead (mid 1950's). I'd like to build a MIDI receiver that would use the 8255 outputs to strike the chimes based on which note was being played and resurrect this machine.
  • CP/M Computer I've always wanted to hook a CF card into my Z-80 computer and make it run some older games and software.

News:

During October 2007 Gary Stephens sent me two Space-Time Production computers that he purchased a while back that he was no longer interested in. One board is completely bare as the day it was born, the other board is fully populated with IC's and some sockets and connectors. I am doing some work on this one to get it fully operational, it is destined for the Pinewood Derby Race Controller and Giant Display.

I will post more information on this as I get farther along in the project.

Notes:

If you own one of these computers, please take a moment to email me.
Also, I'm interested in what you are doing with your Space-Time Productions computer, and would like to include that information in my website. Photos are welcome as well.

ALSO: If you bought one of these boards a while back and aren't using it, please contact me. They are increasingly rare and the IC's that were sold in the "kits", such as the Z-80 SIO and the Intel P8279, P8253 and P8255 chips are in short supply as well. Thanks!

Are you missing some chips for your Space-Time computer? I have a wealth of DIP type IC's, several Z-80 CPU's, 74LSxx series logic, the resistor network DIP, plenty of 2732 4Kx8 Eproms if you need your program burned onto a chip just for your particular application - Let me know!

My Z-80 Computer

Click HERE if you do not see a menu frame to the left.

This site created September 2004.

All information contained herein that is generated by Joel Owens ©2007.
Other information credited to its sources.
This site is not affiliated with Space-Time Productions, Mr. M. Simon, or Mr. Ron Weiss, however I extend a grateful Thanks to those parties.
This site has a sole purpose to provide technical information, and is not intended to infringe any prior
copyrights nor to derive funds that would otherwise be the property of Microsoft, Space-Time Productions
or it affiliates, either past or present.