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MicroBee

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MicroBee(orMicro Bee) was a series of networkablehome computersbyApplied Technology,which became publicly listed company MicroBee Systems Limited soon after its release. The original Microbee computer was designed inAustraliaby a team including Owen Hill[1]and Matthew Starr.

MicroBee
DeveloperApplied Technology
TypeHome computers
Release dateFebruary 1982;42 years ago(1982-02)
Introductory priceA$399in Kit Form
Discontinued1990;34 years ago(1990)
Operating systemMicroWorldBASIC
DGOS (David Griffiths Operating System)
CPUZilog Z80@2 MHz
Memory16kBor32kB
GraphicsSynertek6545CRT controllerfor64 × 16characters (512 × 256pixels)
SoundMonotonic sound generator & speaker, 2octaves

The MicroBee's most distinctive features are its user configurable video display (capable of mimicking the displays of other computers and devices including theTRS-80,Sorcerer and SOL20 with later colour and graphic models 40 and 80 column terminals, Super-80,ZX Spectrum,early arcade machines,Amstrad CPC 464) and its battery backednon-volatile RAMand small size allowing it to be powered off, transported, and powered back on and resume activities on the currently loaded program or document.

It was originally packaged as a two board unit with the lower "baseboard" containing all components except the system memory which was mounted on the upper "core board".

Components

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The original main board consisted of:

The original coreboards consisted of:

  • Either 32KB capacity or 56KB capacity 6116 battery backed Non-volatile RAM
  • Either 16KB BASIC ROM or 4KB BOOT ROM
  • 50 way System Expansion port
  • Provision for 8KB Expansion ROM on 32KB Max capacity version

A floppy disk drive unit andS-100 busexpansion unit were available. They connected to a microbee by a 50 wayribbon cableto the System Expansion port.

The microbee had two networking options - BeeNet and StarNet. The BeeNet was a low cost low speed LAN (Local Area Network) for 16-32K ROM Models and the StarNet was for the 64K and larger DRAM models.

The BeeNet uses abus topologythat usessynchronousserial transfers. The StarNet uses a singlestar topologyusing dedicated 8-bit parallel data bus connections between the central hub and its remote spokes.

Ancestry

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The microbee was the integration, simplification and modernisation of the following S-100 cards sold by Applied Technology, Microworld BASIC and DGOS Monitor for their System Z.A.T. chassis.

  • DG680 CPU - Z80 Single board Computer designed by David Griffiths
  • MW640/DG640 VDU - Visual Display Unit designed by David Griffiths. (The DG640 VDU was itself was based upon the Processor Technology VDM-1.)
  • TCT-PCG - Programmable Character Generator for the DG640 VDU designed by Craig Barratt
  • MW864 - MEGAMEMORY 64KStatic RAMMemory board designed by Owen Hill
  • MW2516 - 16K ROM 16K ROM Card designed by Owen Hill
  • MW6545 - User Programmable VDU designed by John Wilmshurst

The removal of the S-100 bus support and configuration hardware and some other features made the microbee much simpler and cheaper than its ancestors.

Examples:

  1. The VDU Attribute RAM of the DG640 VDU was not employed in the original microbee (but was reinstated in a modified and extended form for the Premium Series Microbee)
  2. Z80 CTC (Counter Timer Counter)
  3. Tape motor on/off control
  4. 8 bit input sense port
  5. ConfigurationDIP switches

The utilisation of higher density memory devices made also the microbee smaller. HM6116 (2K x 8 bit) were instead of the earlier 2101 (1K x 1bit) and 2114 (1K x 4bit) static RAMS and 2732 (4K x 8 bit) ROMs instead of 2516 (2K x 8) ROMs as program ROM. Subsequent models used the even denser HM6264 (8K x 8 bit) static RAMs, 4164 (64K x 1 bit) dynamic RAM and 27128 (16K x 8 bit) 2764 (8K x 8) program ROMs.

Kit beginnings

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The computer was released as a kit, with assembly instructions included inYour Computermagazine, in February 1982.[2]After a successful bid for theNew South WalesDepartment of Education computer tender, the computer was repackaged in a two-tone beige and black case, and sold pre-built. The16 kBROMheld the MicroWorldBASICinterpreter written by Matthew Starr and DGOS (David Griffiths Operating System) compatible System Monitor. In addition to the16 kB ROM,there is additional ROM socket for optional programs such as WORDBEE (Word processor) or EDASM (a Z80 Editor/Assembler that was written by Ron Harris).[3]

Original MicroBees ran at aclock speedof2 MHz,with a video dot clock of12 MHz,which was sufficient to display64 × 16 characters(512 × 256 pixels) on a modifiedtelevisionorcomposite monitor.The original machines were supplied with16 or 32 kBofstatic RAM,and stored programs oncassette,using 300 or 1200Baudencoding.

The IC model

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The IC model was released in 1983, increasing the clock speed to3.375 MHz,and allowing (through use of a13.5 MHzvideo clock) display of80 × 24 characters(640 × 264 pixels), again on a modified television or composite monitor. It also included a4 kB"Telcom" terminal emulatorROM.

A complete MicroBee Computer-In-A-Book system

Disk machines

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A floppy disk based machine was also released in 1983. Early disk machines used56 kBofstatic RAM,with a4 kBBIOSROM.They ranCP/M2.2. Thedisk controller,based on theWestern DigitalWD1793Floppy Disk Controllerchip was contained in an add-on card that connected to the core board. The machine used 5.25 "floppy disks.

Dynamic RAMdisk machines with64 or 128 kBRAMfollowed soon after, with a WD2793 Floppy Disk Controller incorporated on the core board. Later disk machines used3.5 "floppy disks.

Colour

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A colour machine was also released in 1983, called the "32K Personal Communicator". This added a second byte of RAM for each character position, allowing each character to have 2 colours. The foreground colour has 32 possible values (5 bits) and are determined by the contents of the 82S123PROMlocated on the colour board. Not all foreground colours combinations are unique with only 27 being possible. The background colours were made up from the remaining 3 bits of the colour RAM byte (8 colours) and another 3 bits on a colour control port that controlled theRGBbackground intensity level. This allowed the intensity of each of the RGB colours to be set to full or half intensity but only 7 different values could be in effect at any one time and changing the intensity value would affect the entire display. The extra colour circuitry required an additional board mounted under the main board, with numerous messy connections to the main board.

The Premium, 256TC and Teleterm models released in 1986 incorporated colour on the main board and used a different colour design compared to the earlier model and was not compatible for the resultant colours that were produced but application and system software will work on either hardware designs. The later colour design was largely compatible with theColor Graphics Adapterused on theIBM PCwhere 4 bits were used for the foreground and another 4 bits for the background colours.

The B-ETI Serial Terminal

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The B-ETI was a Microbee-based serial terminal. It could emulate either anADM-3AorTelevideo912 terminal. The display format was monochrome80 × 24and it supported communication at either 300 or 1200baud.An advertisement for a "special introductory offer" with an asking price ofA$275appeared in the December 1983 issue ofElectronics Today Internationalmagazine.[4]

Introduction, BETI Users Guide:

The BETI was designed as a low cost serial terminal operating at speeds of up to 4800 baud (1200 baud withouthandshaking). The BETI also provides optional automatic code conversion to and from thebaudot5 level code used forRTTYandTelexapplications.

Specifications:[5]

  • Codes supported: US ASCII and CCITT BAUDOT.
  • Baud rates: 45.5, 50, 75, 110, 300, 600, 1200, 2400, 4800.
  • Default settings: 4800 baud USASCIIfull duplex.
  • Emulation: ADM-3A and TVI 912C (except for attributes).
  • RS232 port: Configured as DTE with 0-12V swing.
  • Parallel port: Connects toCentronicsprinter with adapter.
  • Internal buffer: 1800 bytes.
  • Power supply read: 9 - 12 V at 800mA.
  • Video output:Composite video:negative sync, 1V p-p into 75 ohms, 50 Hz frame, 15625 Hz line frequency.
  • Screen format: 80 characters by 24 for lines, 64 by 16 lines for setup mode.
  • Attribute: Reverse video, enabled byescape sequence.
  • Keyboard: Full size, 60-keyQWERTYlayout, positive travel. Two shot moulded key tops.
  • Microprocessor: Z80A at 3.375 MHz.
  • Control program: 4k 2532EPROM.
  • Sound generation: Built in loudspeaker for BELL.
  • Case: 342mm W × 239mm D × 42mm H.Injection mouldedABS.

The Premium Series MicroBee

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In 1985, a new mainboard was introduced. The resulting machine was called the "Premium Series" model. The new mainboard had8 kBof screenRAM,8 kBof "attribute" RAM (raising the possible number of PCG characters to32 768),8 kBof colour RAM, and up to32 kB(16 kBinstalled) of PCG RAM.16 kBPCG RAM was sufficient to allow full512 × 256 bitmapped displays with a limited colour palette. These machines were typically sold with dual-floppy drives (or a10 MB'Winchester' disc) held in a monitor stand that connected to the main unit.

Physical coding for tape storage

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Microbee 32K IC

Standard MicroBee Tapes are encoded at300 or 1200 baudusing its own variation of Processor Technology's SOLOS/CUTER Tape protocol[6]that consists of a 300 baud metadata header followed by data payload blocks encoded at the desired transfer rate using CUTS (Computer Users Tape System).[7]

Thewav2datsoftware converts audio data into Microbee files.

Books

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A few books were written about the Microbee, including:

  • Wildcards- By Robert Alan Burt, Peter Terence Ford, and Ash Nallawalla[8]
  • Wildcards 2- By Robert Alan Burt, Peter Terence Ford, and Ash Nallawalla[9]
  • Wildcards 3- By Robert Alan Burt, Peter Terence Ford, and Ash Nallawalla[10]
  • Wildcards 4- By Robert Alan Burt, Peter Terence Ford, and Ash Nallawalla[11]
  • Getting started on your MicroBee- By Petr Lukes and Tim Hartnell[12]
  • Shake hands with the Microbee- By Pam Kelly-Hartley, Joy McKneil and Tony Melius[13]
  • The Penguin book of Microbee games- By David Johns and edited by Tim Hartnell[14]
  • The Winners- compiled by the Sydney Microbee User's Group[15]

Games

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Games for the MicroBee include both original titles and clones of pre-existing games, including:

  • Asteroids
  • Bunyip Adventure,atext adventure[16]
  • Cricket
  • Emu Joust- aJoustclone
  • Gorilla Maths- a mental maths challenge with inklings of Donkey Kong
  • Halloween Harry
  • Hoards of the Deep Realm[17]
  • Lemonade Stall- a game for budding business entrepreneurs.
  • Microspace Invaders
  • Robotman- aPac-Manclone by Paul Wilmhurst[18]
  • Scrambler
  • Sword Quest- aDungeons & Dragonsstyle game by P Jepson and C Temple[19]
  • Toady- a word guessing game
  • Underworld of Kin- By Andy William Farrell
  • Wumpus

As well, numerousadventure gameswere written, mainly inBASIC,plus educational software.[20][21]

Final versions

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The final version of the MicroBee, released in 1987, was the 256TC. This increased the memory to256 kBofdynamic RAMand had a new keyboard with numeric keypad. The computer had a built in3.5 "floppydisk drive supporting both800 kB(DSDD) and400 kB(SSDD) formats. Bundled software included "Videotex" (avideotexterminal program), "Simply Write" (a word processor) and "Telcom" (a serial terminal emulator program).

MicroBee Systemsalso designed aPC clone,called the "Matilda", or 640TC, which ran an NEC V40 (seeNEC V20chip), and emulated the MicroBeeCP/Msystems in software.

An advanced next generation model code named "Gamma", based on theMotorola 68010and twoZilog Z80processors, was designed but never made it to the market.[22][23]

In 1992, after having undergone a number of ownership changes, the company ceased trading.[24]

Legacy

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After almost 20 years, the Microbee brand was re-launched in 2012 by Microbee Technology Pty Ltd, run by a Microbee employee from the 1980s, Ewan Wordsworth.[24]The company produced a limited edition (100 unit only) kit, the Premium Plus. The new version was still Z80-based and followed the original two-board design. It had dual-processor architecture, with some enhancements such as floppy emulation of theSD memory card.[25]

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In the '80s parody movieKung Fury,Hackerman is hacking the timeline with MicroBee computers (along with aZX Spectrumand aPower Glove) and Kung Fury himself also rides in the cyberspace on a MicroBee.[26]

References

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  1. ^Secret of project Granny SmithBy Gordon Laing, July 12, 2005 - theage.au
  2. ^Microbee computer,From:Owen Hill Date:24 Aug 1998, Link list on Australian network policy and communications
  3. ^Graphic Word bee user's manualby Ron Harris and Gordon Rowell, Honeysoft, c1985., National Library of Australia
  4. ^B-ETI Advertisement. (December 1983).Electronics Today International,p. 51.
  5. ^"BETI Serial Terminal Operator's Guide", Microbee Technology.
  6. ^"User's manual"(PDF).sol20.org.RetrievedJune 29,2023.
  7. ^Robert M. Marsh."Computer users tape system"(PDF).sol20.org.RetrievedJune 29,2023.
  8. ^Burt, Robert; Ford, Peter T.; Ash Nallawalla (1983).Wildcards.Australia: BF&N Publishing. p. 100.ISBN0949127000.
  9. ^Burt, Robert; Ford, Peter T; Ash Nallawalla (1983).Wildcards 2.Australia: BF&N Publishing. p. 120.ISBN0949127019.
  10. ^Burt, Robert; Ford, Peter; Ash Nallawalla (1985).Wildcards 3.Melbourne: Pitman. p. 109.ISBN0858962039.
  11. ^Burt, Robert; Ford, Peter; Ash Nallawalla (1985).Wildcards 4.Melbourne: Pitman. p. 122.ISBN0858962020.
  12. ^Lukes, Petr (1984).Getting Started on your Microbee.Australia: Pitman. p. 105.ISBN0858960869.
  13. ^Kelly-Hartley, Pam (1985).Shake hands with the Microbee.Australia: Pitman. p. 127.ISBN0858960990.
  14. ^Johns, David (1983).The Penguin book of Microbee games.Australia: Penguin. p. 104.ISBN0140078916.
  15. ^The Winners.Australia: Honeysoft Publishing. 1985. p. 57.ISBN0949309397.
  16. ^"Bunyip Adventure".Play It Again.RetrievedAugust 13,2024.
  17. ^"Hoards of Deep Realm".RetrievedJune 29,2023.
  18. ^MBEE - Microbee (Australian),The Giant List of Classic Game Programmers
  19. ^Old computers museum[dead link‍]
  20. ^Chilly Willy & Halloween Harryby John Passfield
  21. ^Ring of Doom / Ödesringen,Produced by: Microworld, Author: Chris Peters, Year: 1983, System: Microbee, Type: Text adventure,Tolkien computer games
  22. ^Microbee Systems:WHEN OWEN HILL STOOD STILLAn interview with Owen Hill, founder of Microbee Systems. Published in Your Computer, February 1986.
  23. ^Gamma,Microbee, The As-Yet Unnamed Computer Museum!!
  24. ^ab"About Us / History".Microbee Technology Pty Ltd.RetrievedOctober 20,2017.
  25. ^"Premium Plus Limited Edition Kit".Microbee Technology Pty Ltd. Archived fromthe originalon April 3, 2013.RetrievedOctober 20,2017.
  26. ^"Kung Fury".
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