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Microbee Series 2 Models

Series 2 models were released in early 1984 (or late 1983?). A new Core board (coded MB1732) was used for all Series 2 models, except the APC. This board supported new 2764 type EPROMs (8KB) for Basic and WordBee/EDASM but retained the earlier 2532 type EPROM (4KB) for Telcom. The schematic shows that the new board could potentially support a 2732 type EPROM in place of the 2532 but it is not known if this type was ever used in production. Aside from the new Core board, the Series 2 machines are technically very similar to the previous Series 1 Microbee IC and Microbee 64K Plus models.
 

Experimenter

Overview

Name
Category
Release Date
Description
Microbee Series 2 Experimenter
Standard
ROM based
1984 (late 1983?)
The Experimenter was the budget model of the Series 2 range and was supplied with only 8KB RAM fitted. This is the only Microbee model ever to be released with less than 16KB RAM. IC sockets were provided on the Core board to allow an additional 8KB RAM to be easily fitted by the customer if required. The Experimenter is rarely seen today so it appears not to have sold in large numbers or customers found 8KB to be too limiting and soon upgraded to larger RAM capacities.

 

Details

Microbee Series 2 Experimenter Brochure
CPU
Zilog Z80 @ 3.375MHz
RAM
8KB total capacity. It is unclear whether the backup battery was fitted as standard to make the RAM non-volatile.
Uses CMOS Static RAM (SRAM), eg Hitachi HM6116 (each 2KB)
ROM
A total of 28K ROM can be fitted:
  • Microworld Basic (16KB). Fitted as standard.
  • WordBee Word Processor or EDASM (8KB). Optional.
  • Telcom (4KB). Fitted as standard.
Uses 2x 2764 EPROMs for Basic, 1x 2764 EPROM for WordBee/EDASM and 1x 2532 or 2732 EPROM for Telcom
Storage
Cassette tape via an external recorder.
Video
Monochrome composite video output using an external monitor. Two main display resolutions are available:
  • 64*16 characters.
  • 80*24 characters.
Uses Synertek 6545 CRT controller.
Graphics
Two graphics modes available using a Programmable Character Generator SRAM (PCG):
  • Low resolution (LORES):
    • 128*48 pixels on a 64*16 character display.
  • High resolution (HIRES):
    • 512*256 pixels on a 64*16 character display.
    • 640*264 pixels on a 80*24 character display.
PCG RAM capacity is 2KB, providing a maximum of 128 unique graphics characters.
Fonts
Dual fonts to support 64*16 and 80*24 character displays. Both fonts support upper and lower case characters (128 characters in total per font).
Uses a single 4KB ROM.
Sound
Internal speaker. Generates sound through software bit bashing.
Keyboard
60 key QWERTY style with a bit-paired layout.
Serial port
An RS232-like serial port using a DB25 socket at the rear. The port is configured as Data Terminal Equipment (DTE) but does not implement all RS232 standard signals and does not provide negative voltages on output. Nevertheless, it is compatible with many standard RS232 peripherals. Microworld Basic uses this port to provide 300 and 1200 baud serial communications through software bit bashing.
Parallel port
8 bit parallel I/O port via a DB15 socket at the rear.
Expansion interface
An interface to the Z80 bus is available at the rear, but the associated 50 way connector is not fitted as standard. This was available as an option.
DIN port
A 5 pin multifunction DIN socket at the rear carries:
  • Power input.
  • Composite video output for connection to a video monitor.
  • Tape recorder output for connection to an external recorder's AUX IN/MIC socket.
  • Tape recorder input for connection to an external recorder's EAR (earphone) socket.
System Clock
The master clock runs at 13.5MHz. This provides a 13.5MHz video dot clock and is divided by 4 to provide the 3.375MHz CPU clock.
Real Time Clock
None
Case
Standard
Power
12V 1A plugpack

 

Included Software
Version
Microworld Basic in ROM
5.22e
Telcom in ROM
1.0

Included Documentation
?

Pricing
$
Microbee Series 2 Experimenter
$399.00
BeeModem
$149.50
RGB Colour Module
$125.00

 

Notes

 


Educator

Overview

Name
Category
Release Date
Description
Microbee Series 2 Educator
Standard
ROM based
1984 (late 1983?)
The Educator is the 16KB RAM model of the Series 2 range. Apart from the new Core board, this model is technically very similar for the Series 1 Microbee 16K IC but, unlike the IC, does not include WordBee in ROM as standard.

 

Details

Microbee Series 2 Educator Brochure
Microbee Series 2 Educator
CPU
Zilog Z80 @ 3.375MHz
RAM
16KB total capacity. Non-volatile (backup battery is fitted).
Uses CMOS Static RAM (SRAM), eg Hitachi HM6116 (each 2KB)
ROM
A total of 28K ROM can be fitted:
  • Microworld Basic (16KB). Fitted as standard.
  • WordBee Word Processor or EDASM (8KB). Optional.
  • Telcom (4KB). Fitted as standard.
Uses 2x 2764 EPROMs for Basic, 1x 2764 EPROM for WordBee/EDASM and 1x 2532 or 2732 EPROM for Telcom
Storage
Cassette tape via an external recorder.
Video
Monochrome composite video output using an external monitor. Two main display resolutions are available:
  • 64*16 characters.
  • 80*24 characters.
Uses Synertek 6545 CRT controller.
Graphics
Two graphics modes available using a Programmable Character Generator SRAM (PCG):
  • Low resolution (LORES):
    • 128*48 pixels on a 64*16 character display.
  • High resolution (HIRES):
    • 512*256 pixels on a 64*16 character display.
    • 640*264 pixels on a 80*24 character display.
PCG RAM capacity is 2KB, providing a maximum of 128 unique graphics characters.
Fonts
Dual fonts to support 64*16 and 80*24 character displays. Both fonts support upper and lower case characters (128 characters in total per font).
Uses a single 4KB ROM.
Sound
Internal speaker. Generates sound through software bit bashing.
Keyboard
60 key QWERTY style with a bit-paired layout.
Serial port
An RS232-like serial port using a DB25 socket at the rear. The port is configured as Data Terminal Equipment (DTE) but does not implement all RS232 standard signals and does not provide negative voltages on output. Nevertheless, it is compatible with many standard RS232 peripherals. Microworld Basic uses this port to provide 300 and 1200 baud serial communications through software bit bashing.
Parallel port
8 bit parallel I/O port via a DB15 socket at the rear.
Expansion interface
An interface to the Z80 bus is available at the rear, but the associated 50 way connector is not fitted as standard. This was available as an option.
DIN port
A 5 pin multifunction DIN socket at the rear carries:
  • Power input.
  • Composite video output for connection to a video monitor.
  • Tape recorder output for connection to an external recorder's AUX IN/MIC socket.
  • Tape recorder input for connection to an external recorder's EAR (earphone) socket.
System Clock
The master clock runs at 13.5MHz. This provides a 13.5MHz video dot clock and is divided by 4 to provide the 3.375MHz CPU clock.
Real Time Clock
None
Case
Standard
Power
12V 1A plugpack

 

Included Software
Version
Microworld Basic in ROM
5.22e
Telcom in ROM
1.0

Included Documentation
?

Pricing
$
Microbee Series 2 Educator
$449.00
BeeModem
$149.50
RGB Colour Module
$125.00

 

Notes

 


Personal Communicator (PC)

Overview

Name
Category
Release Date
Description
Microbee Series 2 Personal Communicator (PC)
Standard
ROM based
1984 (late 1983?)
The Personal Communicator is the 32KB RAM model of the Series 2 range. Apart from the new Core board, this model is technically very similar for the Series 1 Microbee 32K IC. The Personal Communicator also includes WordBee as standard like the IC, but unlike the lower cost Experimenter and Educator models.

 

Details

Microbee Series 2 Personal Communicator Brochure
CPU
Zilog Z80 @ 3.375MHz
RAM
32KB total capacity. Non-volatile (backup battery is fitted).
Uses CMOS Static RAM (SRAM), eg Hitachi HM6116 (each 2KB)
ROM
A total of 28K ROM can be fitted:
  • Microworld Basic (16KB). Fitted as standard.
  • WordBee Word Processor (8KB). Fitted as standard.
  • Telcom (4KB). Fitted as standard.
Uses 2x 2764 EPROMs for Basic, 1x 2764 EPROM for WordBee/EDASM and 1x 2532 or 2732 EPROM for Telcom
Storage
Cassette tape via an external recorder.
Video
Monochrome composite video output using an external monitor. Two main display resolutions are available:
  • 64*16 characters.
  • 80*24 characters.
Uses Synertek 6545 CRT controller.
Graphics
Two graphics modes available using a Programmable Character Generator SRAM (PCG):
  • Low resolution (LORES):
    • 128*48 pixels on a 64*16 character display.
  • High resolution (HIRES):
    • 512*256 pixels on a 64*16 character display.
    • 640*264 pixels on a 80*24 character display.
PCG RAM capacity is 2KB, providing a maximum of 128 unique graphics characters.
Fonts
Dual fonts to support 64*16 and 80*24 character displays. Both fonts support upper and lower case characters (128 characters in total per font).
Uses a single 4KB ROM.
Sound
Internal speaker. Generates sound through software bit bashing.
Keyboard
60 key QWERTY style with a bit-paired layout.
Serial port
An RS232-like serial port using a DB25 socket at the rear. The port is configured as Data Terminal Equipment (DTE) but does not implement all RS232 standard signals and does not provide negative voltages on output. Nevertheless, it is compatible with many standard RS232 peripherals. Microworld Basic uses this port to provide 300 and 1200 baud serial communications through software bit bashing.
Parallel port
8 bit parallel I/O port via a DB15 socket at the rear.
Expansion interface
An interface to the Z80 bus is available at the rear, but the associated 50 way connector is not fitted as standard. This was available as an option.
DIN port
A 5 pin multifunction DIN socket at the rear carries:
  • Power input.
  • Composite video output for connection to a video monitor.
  • Tape recorder output for connection to an external recorder's AUX IN/MIC socket.
  • Tape recorder input for connection to an external recorder's EAR (earphone) socket.
System Clock
The master clock runs at 13.5MHz. This provides a 13.5MHz video dot clock and is divided by 4 to provide the 3.375MHz CPU clock.
Real Time Clock
None
Case
Standard
Power
12V 1A plugpack

 

Included Software
Version
Microworld Basic in ROM
5.22e
WordBee in ROM
1.2
Telcom in ROM
1.0

Included Documentation
?

Pricing
$
Microbee Series 2 Personal Communicator
$499.00
BeeModem
$149.50
RGB Colour Module
$125.00

 

Notes

 


Advanced Personal Computer (APC)

Overview

Name
Category
Release Date
Description
Microbee Series 2 Advanced Personal Computer (APC)
Standard
Disk based
1984 (late 1983?)
The Advanced Personal Computer (APC) is the Series 2 incarnation of the earlier Series 1 Microbee 64K Plus. There appears to be no technical difference between the APC and the 64K Plus machines. Both use the same Core board (coded MB1656) to provide 56KB RAM (SRAM) and 4KB Boot/Monitor ROM. The external disk unit is also unchanged from the 64K Plus and still uses 5.25" DSDD 40 track disk drives to provide 390KB formatted disk capacity.

 

Details

Microbee Series 2 Advanced Personal Computer Brochure
CPU
Zilog Z80 @ 3.375MHz
RAM
56KB total capacity (not 64K as you might think from the name). Non-volatile (backup battery is fitted).
Uses CMOS Static RAM (SRAM), eg Hitachi HM6116 (each 2KB)
ROM
4KB Boot/Monitor ROM (a single 2532 or 2732 EPROM)
Storage
Either:
  • Half height 5.25" DSDD 40 track floppy disk (386K capacity) via an external disk unit. Up to 4 disk drives can be fitted, or
  • Cassette tape via an external recorder
Video
Monochrome composite video output using an external monitor. Two main display resolutions are available:
  • 64*16 characters (for Basic)
  • 80*24 characters (for CP/M)
Uses Synertek 6545 CRT controller.
Graphics
Two graphics modes available using a Programmable Character Generator SRAM (PCG):
  • Low resolution (LORES):
    • 128*48 pixels on a 64*16 character display.
  • High resolution (HIRES):
    • 512*256 pixels on a 64*16 character display.
    • 640*264 pixels on a 80*24 character display.
PCG RAM capacity is 2KB, providing a maximum of 128 unique graphics characters.
Fonts
Dual fonts to support 64*16 and 80*24 character displays. Both fonts support upper and lower case characters (128 characters in total per font).
Uses a single 4KB ROM.
Sound
Internal speaker. Generates sound through software bit bashing.
Keyboard
60 key QWERTY style with a bit-paired layout.
Serial port
An RS232-like serial port using a DB25 socket at the rear. The port is configured as Data Terminal Equipment (DTE) but does not implement all RS232 standard signals and does not provide negative voltages on output. Nevertheless, it is compatible with many standard RS232 peripherals. Microworld Basic uses this port to provide 300 and 1200 baud serial communications through software bit bashing.
Parallel port
8 bit parallel I/O port via a DB15 socket at the rear.
Expansion interface
An interface to the Z80 bus is available at the rear with 50 way connector fitted as standard in this model. This interface is used to attach an external floppy drive unit.
DIN port
A 5 pin multifunction DIN socket at the rear carries:
  • Power input.
  • Composite video output for connection to a video monitor.
  • Tape recorder output for connection to an external recorder's AUX IN/MIC socket.
  • Tape recorder input for connection to an external recorder's EAR (earphone) socket.
System Clock
The master clock runs at 13.5MHz. This provides a 13.5MHz video dot clock and is divided by 4 to provide the 3.375MHz CPU clock.
Real Time Clock
None
Case
Standard
Power
If attached, power is supplied from the external disk unit via the 50 way Expansion interface. Otherwise, a standard 12V 1A plugpack can be used to supply power via the DIN connector. Both sources of power should not be used at the same time as a ground loop can develop leading to video interference.

 

Included Software
Version
Boot/Monitor in ROM
?
Microworld Basic on disk
EDASM on disk

Included Documentation
?

Pricing
$
Microbee Series 2 APC with single 5.25" DSDD disk drive
$1495.00
Microbee Series 2 APC with dual 5.25" DSDD disk drives
$1795.00
Additional 5.25" DSDD disk drive
$300.00
BeeModem
$149.50
RGB Colour Module
$125.00

 

Notes

  • While the usual configuration for this machine is to have an external disk unit connected and to automatically boot CP/M from disk on power up, it can also be used in a diskless configuration:
    • By default, the machine will boot to a blank screen with an inverse block displayed in the top left corner of the display. It will remain in this mode indefinitely, looking for a disk to boot from.
    • To use the machine without a disk, hold down the 'M' key during power up (or during a manual Reset) to invoke the Microbee Disk Monitor program.
    • Use the Monitor to load Microworld Basic (v5.22e) from tape using the 'R' command. Once Basic has been loaded it can be invoked with the 'G' command - 'G 8000'.
    • An optional coreboard switch allows the RAM address range of 8000H - DFFFH to be write protected once loaded with Basic and other tape versions of EDASM, WordBee, etc.
    • With pre-loaded write protected non-volatile RAM the APC can then effectively be used in the same way as the other Series 2 ROM based models.