Acorn BBC Master Turbo

The Acorn BBC Master Turbo combined a Master 128 with an internal 4 MHz 65C102 second processor and its own 64KB memory. Compatible software could run substantially faster while the host machine handled input, display and storage.

It brought Acorn’s established Tube co-processor architecture inside the computer and represented the fastest official 6502-family BBC system.

Notable Features

• 65C12 at 2 MHz with internal 65C102 co-processor at 4 MHz forms the centre of the system.
• The standard memory and storage configuration was 128KB host RAM plus 64KB co-processor RAM and Cassette and built-in WD1770 floppy controller.
• Its principal display arrangement was Television, composite video or RGB monitor.

Historical Significance

• It brought Acorn’s established Tube co-processor architecture inside the computer and represented the fastest official 6502-family BBC system.
• This page represents a distinct Acorn model rather than a regional, memory-only or bundled-software variation.

Collector’s Notes

• Original keyboards, power supplies, manuals, expansion cards and storage hardware materially improve a surviving system.
• Internal revisions and dealer-installed upgrades mean an individual machine should be checked against its serial label and fitted hardware.

Specifications

Technical Information
Name	Acorn BBC Master Turbo
Manufacturer	Acorn Computers
Launched	Wednesday, January 1, 1986
Discontinued	1993
Country	United Kingdom
CPU	65C12 at 2 MHz with internal 65C102 co-processor at 4 MHz
Units Sold
Operating System	Master MOS 3.20 with BBC BASIC IV and Tube software
I/O	Master interfaces, Tube architecture, cartridge slots and optional Econet
Keyboard	Integrated keyboard with numeric keypad and ten function keys
Storage	Cassette and built-in WD1770 floppy controller
Sound	Texas Instruments SN76489; three tone channels plus noise
Graphics	BBC display modes with shadow-screen memory
Display	Television, composite video or RGB monitor
ROM	128KB Master ROM plus co-processor firmware
RAM	128KB host RAM plus 64KB co-processor RAM
CPU Speed	2 MHz host; 4 MHz co-processor