16–32 KiB (Model A/B)
64–128 KiB (Model B+)
128 KiB (Master)
Plus 32–128 KB ROM, expandable to 272 KiB
100–800 KB (DFS)
160–1280 KB (ADFS floppy disks)
20 MB (ADFS hard disk)
UHF /composite /TTL
640×256, 8 colours (various framebuffer modes)
78×75, 8 colours (
Texas Instruments SN76489 , 4 channels, mono
TMS5220 speech synthesiser with phrase ROM (optional)
Keyboard, twin analogue joysticks with fire buttons, lightpen
RS-423 serial, user parallel,
1 MHz bus, Tube second processor interface
BBC MICROCOMPUTER SYSTEM, or
BBC MICRO, is a series of
microcomputers and associated peripherals designed and built by the
Acorn Computer company for the
BBC Computer Literacy Project, operated
by the British Broadcasting Corporation . Designed with an emphasis on
education, it was notable for its ruggedness, expandability, and the
quality of its operating system . An accompanying 1982 television
The Computer Programme " featuring
Chris Serle learning to use
the machine was also broadcast on
BBC 2 .
After the Literacy Project's call for bids for a computer to
accompany the TV programmes and literature, Acorn won the contract
with the Proton, a successor of its Atom computer prototyped at short
notice. Renamed the
BBC Micro, the system was adopted by most schools
United Kingdom , changing Acorn's fortunes. It was also
moderately successful as a home computer in the UK despite its high
cost. Acorn also employed the machine to simulate and develop the ARM
architecture which, many years later, has become hugely successful for
embedded systems , including tablets and cellphones . In 2013 ARM was
the most widely used
32-bit instruction set architecture .
While nine models were eventually produced with the
BBC brand, the
BBC Micro" is usually used colloquially to refer to the first
six (Model A, B, B+64, B+128, Master 128, and Master Compact),
Acorn Electron ; subsequent
BBC models are considered as
part of Acorn\'s Archimedes series.
* 1 History
* 2 Market impact
* 3 Description
* 3.1 Hardware features: Models A and B
* 3.1.1 Export models
* 3.1.2 Side product
* 3.2 Hardware features
* 3.2.1 B+64 and B+128
* 3.3 Software and expandability
* 3.4 Peripherals
BBC BASIC built-in programming language
* 3.4.2 Other languages
* 4 Successor machines
* 5 Retro computing scene
* 5.1 Continued development and support
* 6 Specifications (Model A to Model B+128)
* 6.1 Display modes
* 6.2 Optional extras
* 7 Use in the entertainment industry
* 8 See also
* 9 References
* 10 External links
BBC Micro team in 2008
During the early 1980s, the
BBC started what became known as the BBC
Computer Literacy Project. The project was initiated partly in
response to an ITV documentary series The Mighty Micro, in which
Christopher Evans of the UK's National Physical Laboratory predicted
the coming microcomputer revolution and its effect on the economy,
industry, and lifestyle of the United Kingdom.
BBC wanted to base its project on a microcomputer capable of
performing various tasks which they could then demonstrate in the TV
The Computer Programme . The list of topics included
programming , graphics , sound and music, teletext , controlling
external hardware, and artificial intelligence . It developed an
ambitious specification for a
BBC computer, and discussed the project
with several companies including
Acorn Computers ,
Sinclair Research ,
Tangerine Computer Systems , and
Dragon Data .
The Acorn team had already been working on a successor to their
existing Atom microcomputer. Known as the Proton, it included better
graphics and a faster 2 MHz
MOS Technology 6502 central processing
unit . The machine was only at the design stage at the time, and the
Acorn team, including
Steve Furber and
Sophie Wilson , had one week to
build a working prototype from the sketched designs. The team worked
through the night to get a working Proton together to show the BBC.
Not only was the Acorn Proton the only machine to match the BBC's
specification, it also exceeded it in nearly every parameter. Based
on the Proton prototype the
BBC signed a contract with Acorn as early
as February 1981; by June the
BBC Micro's specifications and pricing
The keyboard of a Model B in close-up
The machine was released as the
Microcomputer on 1 December 1981,
although production problems pushed delivery of the majority of the
initial run into 1982. Nicknamed "the Beeb", it was popular in the
UK, especially in the educational market; about 80% of British schools
BYTE called the
BBC Micro Model B "a no-compromise computer that has
many uses beyond self-instruction in computer technology". It called
the Tube interface "the most innovative feature" of the computer, and
concluded that "although some other British microcomputers offer more
features for a given price, none of them surpass the
BBC ... in terms
of versatility and expansion capability". As with Sinclair 's ZX
Spectrum and Commodore 's
Commodore 64 , both released later in 1982,
demand greatly exceeded supply. For some months, there were long
delays before customers received the machines they had ordered.
Efforts were made to market the machine in the United States and West
Germany. By October 1983, the US operation reported that American
schools had placed orders with it totalling $21 million. In October
1984, while preparing a major expansion of its US dealer network,
Acorn claimed sales of 85 per cent of the computers in British
schools, and delivery of 40,000 machines per month. That December,
Acorn stated its intention to become the market leader in US
The New York Times
The New York Times considered the inclusion of
local area networking to be of prime importance to teachers. The
operation resulted in advertisements by at least one dealer in
Interface Age magazine, but ultimately the attempt failed. The
success of the machine in the UK was due largely to its acceptance as
an "educational" computer – UK schools used
BBC Micros to teach
computer literacy , information technology skills and a generation of
games programmers. Acorn became more known for its model B computer
than for its other products. Some Commonwealth countries, including
India , started their own Computer Literacy programs around 1987 and
BBC Micro, a clone of which was produced by Semiconductor
Complex Limited and named the SCL Unicorn.
The Model A and the Model B were priced initially at £235 and £335
respectively, but increasing almost immediately to £299 and £399 due
to increased costs. The Model B price of nearly £400 was roughly
£1200 (€1393) in 2011 prices. Acorn anticipated the total sales
to be around 12,000 units, but eventually more than 1.5 million BBC
Micros were sold.
The cost of the
BBC Models was high compared to competitors such as
ZX Spectrum and the Commodore 64, and from 1983 on Acorn attempted
to counter this by producing a simplified but largely compatible
version intended for game playing, the 32K
Acorn Electron .
HARDWARE FEATURES: MODELS A AND B
Rear of the
BBC Micro. Ports from left to right:
UHF out , video
RS-423 , cassette, analogue in and
The Model A had 16 KB of user RAM, while the Model B had 32 KB. A
feature that the Micro shared with other 6502 computers such as the
Apple and the early Commodore models was that the RAM was clocked
twice as fast as the CPU, with alternating access given to the CPU
and the video display controller . This gave the
BBC Micro a fully
unified memory address structure without speed penalties. To use the
CPU at full speed (2 MHz ) required the memory system to be capable of
performing four million access cycles per second.
Hitachi was the only
company, at the time, that made a DRAM that went that fast. So for the
prototype the only four 4816s in the country got hand-carried by the
rep. Most competing microcomputers with memory-mapped display
CPU speed penalties depending on the actions of the video
circuits (e.g. the
Amstrad CPC and to a lesser extent the ZX Spectrum
) or kept video memory completely separate from the
CPU address pool
The machine included a number of extra input/output interfaces:
serial and parallel printer ports; an
8-bit general purpose digital
I/O port; a port offering four analogue inputs, a light pen input, and
switch inputs; and an expansion connector (the "1 MHz bus") that
enabled other hardware to be connected. Extra ROMs could be fitted
(four on the PCB or sixteen with expansion hardware) and accessed via
paged memory. An
Econet network interface and a disk drive interface
were available as options. All motherboards had space for the
electronic components, but
Econet was rarely fitted. Additionally, an
Acorn proprietary interface named the "Tube " allowed a second
processor to be added. Three models of second processor were offered
by Acorn, based on the 6502 , Z80 and 32016 CPUs. The Tube was later
used in third-party add-ons, including a
Zilog Z80 board and hard disk
drive from Torch that allowed the
BBC machine to run
Separate pages, each with a codename, were used to control the access
to the I/O:
0xFC00 – 0xFCFF
1 MHz bus
0xFD00 – 0xFDFF
1 MHz bus / paged RAM
0xFE00 – 0xFEFF
Mapped I/O for resident hardware – video, cassette, sound,
The Tube interface allowed Acorn to use
BBC Micros with ARM CPUs as
software development machines when creating the
Acorn Archimedes .
This resulted in the ARM development kit for the
BBC Micro in 1986,
priced at around £4000. From 2006 a kit with an ARM7TDMI
at 64 MHz, with as much as 64 MB of RAM, was released for the BBC
Micro and Master, using the Tube interface to upgrade the old 8-bit
RISC machines. Among the software that operated on
the Tube were an enhanced version of the Elite video game (see below)
and a computer-aided design system that required a second 6502
a 5-dimensional joystick named a "Bitstik".
The Model A and the Model B were built on the same printed circuit
board (PCB) and a Model A could be upgraded to a Model B without too
much difficulty. Users wishing to operate Model B software needed only
to add the extra RAM and the user/printer 6522 VIA (which many games
used for timers) and snip a link, a task that could be achieved
without soldering. To do a full upgrade with all the external ports
did, however, require soldering the connectors to the motherboard. The
original machines shipped with "OS 0.1", with later updates advertised
in magazines, supplied as a clip-in integrated circuit, with the last
official version being "OS 1.2". Variations in the Acorn OS exist as a
result of home-made projects and modified machines can still be bought
on internet auction sites such as eBay , as of 2011.
BBC Model A was phased out of production with the introduction of
the Electron , with chairman Chris Curry stating at the time that
Acorn "would no longer promote it" (the Model A).
BBC Micros used linear power supplies at the insistence of the
BBC's engineering specification, but these very hot-running PSUs were
soon replaced in production by switched mode units.
An apparent oversight in the manufacturing process resulted in a
significant number of Model Bs producing a constant buzzing noise from
the built-in speaker. This fault could be rectified partly by
soldering a resistor across two pads.
There were five developments of the main
BBC micro circuit board that
addressed various issues through the models production, from 'Issue 1'
through to 'Issue 7' with variants 5 and 6 not being released. The
Microcomputer Service Manual' from Acorn documented the
details of the technical changes.
Watford Electronics comments in their '32K Ram Board Manual':
Early issue BBCs (Issue 3 circuit boards and before) are notorious
for out of specification timings. If problems occur with this sort of
machine, the problem can generally be cured by the use of either a
CPU chip, or by replacing IC14 (a 74LS245) with either
another 74LS245 or the faster 74ALS245.
Advert in Interface Age magazine, November 1983, 'The BBC
Microcomputer Is Here!'
Two export models were developed: one for the US, with
speech hardware as standard; the other for
West Germany . Both were
fitted with radio frequency shielding as required by the respective
countries, and they were still based on the Intel 8271 floppy drive
controller. From June 1983 the name was always spelled out completely
– "British Broadcasting Corporation
Microcomputer System" – to
avoid confusion with Brown, Boveri "> Elite (
Acornsoft , 1984). The
unusual game screen used two display modes at once, to show both
detail and colour.
BBC Micro platform amassed a large software base of both games
and educational programs for its two main uses as a home and
educational computer. Notable examples of each include the original
release of Elite and Granny\'s Garden . Programming languages and
some applications were supplied on ROM chips to be installed on the
motherboard. These loaded instantly and left the RAM free for programs
Although appropriate content was little-supported by television
broadcasters, telesoftware could be downloaded via the optional
Teletext Adapter and the third-party teletext adaptors that emerged.
The built-in operating system,
Acorn MOS , provided an extensive API
to interface with all standard peripherals, ROM-based software and the
screen. Features private to some versions of BASIC, like vector
graphics , keyboard macros , cursor-based editing, sound queues and
envelopes , were placed in the MOS ROM and made available to any
BBC BASIC itself, being in a separate ROM, could be
replaced with any equivalent language.
BASIC, other languages and utility ROM chips resided in any of four
16 KB paged ROM sockets, with OS support for sixteen sockets via
expansion hardware. The five (total) sockets were located partially
obscured under the keyboard, with the leftmost socket hard-wired for
the OS. While the original usage for the perforated panel on the left
of the keyboard was for a Serial ROM or Speech ROM, a ZIF socket or
edgecard connector could be installed in that location instead. The
socket could be connected to one of the empty Sideways/PagedROM
sockets via a header cable. The paged ROM system was essentially
modular. A language-independent system of star commands, prefixed with
an asterisk, provided the ability to select a language (for example
*BASIC, *PASCAL), a filing system (*TAPE, *DISC), change settings
(*FX, *OPT) or carry out ROM-supplied tasks (*COPY, *BACKUP) from the
command line. The MOS recognised a handful of built-in commands, and
polled the paged ROMs in descending order for service otherwise; if
none of them claimed the command then the OS returned a Bad command
error. Connecting an external EPROM programmer, one could write
extensive programs, copy to programmable ROM (PROM) or EPROM, then
invoke them without taxing user memory. Main article: Sideways address
Not all ROMs offered star commands (ROMs containing data files, for
instance), but any ROM could "hook " into certain vectors to enhance
the system's functionality. Often the ROM was a device driver for mass
storage combined with a filing system, starting with Acorn's 1982 Disc
Filing System whose
API became the de facto standard for floppy disc
access. The Acorn
Graphics Extension ROM (GXR) expanded the VDU
routines to draw geometric shapes, flood fills and sprites. During
Micro Power designed and marketed a Basic Extension ROM,
introducing statements such as WHILE, ENDWHILE, CASE, WHEN, OTHERWISE,
and ENDCASE, as well as direct mode commands including VERIFY.
Acorn strongly discouraged programmers from directly accessing the
system variables and hardware, favouring official system calls . This
was ostensibly to make sure programs kept working when migrated to
coprocessors that utilised the Tube interface, but it also made BBC
Micro software more portable across the Acorn range. Whereas
untrappable PEEKs and POKEs were commonly used by other computers to
reach the system elements, programs in either machine code or BBC
BASIC would instead pass parameters to an operating system routine. In
this way the MOS could translate the request for the local machine or
send it across the Tube interface, as direct access was impossible
from the coprocessor. Published programs largely conformed to the API
except for games, which routinely engaged with the hardware for
greater speed, and thus required a particular Acorn model.
As the early
BBC Micros had ample I/O allowing machines to be
interconnected, and as many schools and universities employed the
Econet networks, numerous networked multiplayer games were
created. With the exception of a tank game, Bolo , few became popular,
in no small measure due to the limited number of machines aggregated
in one place. A relatively late but well documented example can be
found in a dissertation based on a ringed
In line with its ethos of expandability Acorn produced its own range
of peripherals for the
BBC Micro, including:
* Tape recorder
* Floppy drive interface upgrade
* Floppy drives (single and double)
Econet networking upgrade
* Winchester disk system
* 6502 Second Processor
* Z80 Second processor (with
CP/M and business software suite)
* 32016 Second processor
* ARM Evaluation System
* Speech synthesiser
* Music 500 synthesiser
* IEEE 488 Interface
Other manufactures also produced an abundance of add-on hardware,
some the most common being:
* Printers, plotters
BBC BASIC Built-in Programming Language
BBC BASIC BASIC prompt after switch-on or hard
The built-in ROM-resident
BBC BASIC programming language interpreter
realised the system's educational emphasis and was key to its success;
not only was it the most comprehensive BASIC compared to other
contemporary implementations but it ran very efficiently and was
therefore fast. Advanced programs could be written without resorting
to non-structured programming or machine code (necessary with many
competing computers). Should one want or need to do some assembly
BBC BASIC featured a built-in assembler that allowed a
very easy mixture of
BBC BASIC and assembler for whatever processor
BBC BASIC was operating on.
BBC Micro was released, many competing home computers used
Microsoft BASIC , or variants typically designed to resemble it.
Compared to Microsoft BASIC,
BBC BASIC featured IF…THEN…ELSE,
REPEAT…UNTIL, named procedures and functions, but retained
GOSUB for compatibility. It also supported high-resolution graphics,
four-channel sound, pointer-based memory access (borrowed from
and rudimentary macro assembly. Long variable names were accepted and
distinguished completely, not just by the first two characters.
Acorn had made a point of not just supporting
BBC Basic but a number
of contemporary languages, some of which were supplied as ROM chips to
fit the spare 'Sideways-ROM' sockets on the motherboard. Other
languages were supplied on tape or disk based.
Programming Languages from Acorn:
* ISO Pascal (2× 16 KB ROM + floppy disk)
* S-Pascal (disk or tape)
BCPL (ROM plus further optional disk based modules)
* Forth (16 KB ROM)
* LISP (disk,tape or ROM)
* Logo (2× 16 KB ROM)
Graphics (disk or tape)
* Micro-PROLOG (16 KB ROM)
* COMAL (16 KB ROM)
* Microfocus CIS COBOL (running under
CP/M on floppy disks via the
Z80 second processor)
Acorn produced their own
32-bit Reduced Instruction Set (RISC) CPU
during 1985, the ARM1. Furber composed a reference model of the
processor on the
BBC Micro with 808 lines of BASIC, and ARM Holdings
retains copies of the code for intellectual property purposes. The
first prototype ARM platforms, the ARM Evaluation System and the A500
workstation, functioned as second processors attached to the BBC
Micro's Tube interface. Acorn staff developed the A500's operating
system in situ through the Tube until, one by one, the on-board I/O
ports were enabled and the A500 ran as a stand-alone computer. With
an upgraded processor this was eventually released during 1987 as four
models in the Archimedes series, the lower-specified two models (512
KB and 1 MB) continuing the
Microcomputer brand with the
distinctive red function keys. Although the Archimedes ultimately was
not a major success, the ARM family of processors has become the
dominant processor architecture in mobile embedded consumer devices,
particularly mobile telephones.
Acorn's last BBC-related model, the
BBC A3000, was released in 1989.
It was essentially a 1 MB Archimedes back in a single case form factor
RETRO COMPUTING SCENE
Hermann Hauser playing a game on a Master in
As of 2005, thanks to its ready expandability and I/O functions,
there are still numbers of
BBC Micros in use, and a retrocomputing
community of dedicated users finding new tasks for the old hardware.
They still survive in a few interactive displays in museums across the
United Kingdom, and the
Jodrell Bank observatory was reported to be
still using a
BBC Micro to steer its 42 ft radio telescope during
2004. The Archimedes came with 65Arthur, an emulator which BYTE
stated "lets many programs for the
BBC Micro run"; other emulators
exist for many operating systems. Clockwise from top left:
Hermann Hauser ,
Andy Hopper ,
Christopher Curry ,
Sophie Wilson ,
Chris Serle , David Kitson, Chris Turner, and Steve
Furber at the
BBC Micro 30th anniversary in 2012
In March 2008, the creators of the
BBC Micro met at the Science
Museum in London. There was to be an exhibition about the computer and
its legacy during 2009.
National Museum of Computing at
Bletchley Park uses
as part of a scheme to educate school children about computer
In March 2012, the
BBC and Acorn teams responsible for the
and Computer Literacy Project met for a 30th anniversary party,
entitled "Beeb@30". This was held at ARM 's offices in Cambridge and
was co-hosted by the
Centre for Computing History .
CONTINUED DEVELOPMENT AND SUPPORT
Long after the "venerable old Beeb" was superseded, additional
hardware and software has been developed. Such developments have
included Sprow's 1999 zip compression utility and a ROM
Y2K bugfix for
BBC Master .
There are also a number of websites still supporting both hardware
and software development for the
BBC micros and Acorn in general.
SPECIFICATIONS (MODEL A TO MODEL B+128)
MOS Technology 6502A at 2 MHz
Rockwell Semiconductor 6512A at 2 MHz
64 KB composed of 32 KB standard memory, 20 KB video (Shadow )
memory and 12 KB extended (special Sideways) memory.
128 KB composed of 32 KB standard memory, 20 KB video (Shadow)
memory and 76 KB extended (Sideways) memory.
32 KB of ROM composed of a 16 KB MOS (Machine Operating System)
chip, and 16 KB read-only paged space defaulting to the
chip. Four paged 16 KB ROM sockets standard, expandable to 16.
48 KB of ROM composed of 16 KB MOS, 16 KB DFS , and 16 KB read-only
paged space defaulting to the
Full-travel keyboard with a top row of ten red-orange function keys
ƒ0–ƒ9. These generated text semigraphics when pressed with CTRL or
SHIFT, and could be programmed with keyboard macros. The arrow keys
and BREAK could also serve as function keys. Links on the keyboard PCB
allowed users to select the behaviour of Shift+Break, and Display Mode
As Model B except
RGB (Optional upgrade, soldering required).
6-pin DIN digital
RGB connector +5 V/0 V, 1 V p-p composite colour
or monochrome video (link S39) and built-in
RF modulator .
As Model B, but Modes 0, 1, 2, and 3 not available due to lack of
Configurable graphics in Modes 0–6 (see table below) based on the
Motorola 6845 CRT controller or Mode 7, a special
Teletext mode, based
Teletext chip and only taking 1 KB of RAM.
Four independent sound channels (one noise and three melodic) using
Texas Instruments SN76489 sound chip . Phoneme-based speech
synthesis using the
TMS5220 with a custom Acorn ROM
(the "PHROM", a
TMS6100 ) of
Kenneth Kendall 's voice (optional).
Tape interface (with a relay operated motor control, controlled via
2 pins on a circular 7-pin
DIN connector ), using the CUTS variation
Kansas City standard data encoding scheme operating at 1200 or
Optional floppy disk interface based initially on the Intel 8271
controller and later on the
WD1770 , also requiring the installation
of the DFS (disk filing system) ROM (and of soldered connector on
Model A). (
5.25" floppy drive usually used) – Densities:
Single-Sided, Single Density, Single-Sided, Double-Density,
Double-Sided, Single-Density and Double-Sided, Double-Density.
Floppy disk controller based on the
Western Digital WD1770
controller and DFS ROM as standard (except ANB51, ANB52 ).
None (lack of memory).
Additional ADFS ROM required, external drive unit connected to the
1 MHz Bus interface. (Winchester Hard disc drives with 5 MB, 10 MB or
20 MB capacities. Maximum of 512 MB per drive, up to four drives).
Optional upgrade, soldering required.
RS-423 serial port.
Optional upgrade, soldering required.
Centronics -compatible parallel port.
Optional upgrade, soldering required.
20-pin IDC "user port" with 8 general purpose digital I/O pins and
two special/trigger sensitive digital pins used for control purposes
(for e.g. a turtle when using the Logo programming language).
Optional upgrade, soldering required.
DA15 socket with four 8/12 bit analogue inputs based on µPD7002 IC
(suitable for two joysticks ), two inputs suitable for pushbuttons and
an input for a light pen .
1 MHz Bus
Optional upgrade, soldering required.
34-pin IDC connector for generic expansion on a "daisy-chain" (used
for connecting hard disks, sound synthesisers etc.).
Optional upgrade, soldering required.
40-pin IDC connector for external second CPU. Options included a
second 6502 , a
Zilog Z80 , the ARM Evaluation System , or a National
Semiconductor 32016 (the latter was either branded "
System – 32016 Second Processor" or "Acorn Computer – Cambridge
Co-Processor"), other vendors added 6809, 6800, 68000 and 68008. A 10
MHz 80186 co-processor from a
BBC Master can be connected through a
co-processor adapter to a
BBC Micro, thus enjoying a limited degree of
Network (Optional extra)
Econet large-scale low-cost networking system – around 100 kbit/s
Motorola 68B54 (standard on US model).
Secondary power output
Power supply for external disk drives, 6-pin, top to bottom, left to
0 V, 0 V
+5 V DC @ 1.25 A, +12 V DC @ 1.25 A,
NC, −5 V DC @75 mA,
IBM PC with the contemporary Color
Graphics Adapter , the
video output of the
BBC Micro could be switched by software between a
number of display modes . These varied between 20 and 40-column text
suitable for a domestic TV, to 80-column text best viewed with a
high-quality RGB-connected monitor (The 80-column mode was often too
blurred to view when using a domestic TV via the
UHF output). The
variety of modes offered applications a flexible compromise between
colour depth, resolution and memory economy. In the first models, the
OS and applications were left with the RAM left over from the display
Mode 7 was a
Teletext mode, extremely economical on memory and an
original requirement due to the BBC's own use of broadcast teletext
(Ceefax). It also made the computer useful as a
Prestel terminal. The
teletext characters were generated on board, for use with monitors and
TV sets without a
Teletext receiver. Train time displays at UK
stations were driven by
BBC Master computers in this mode until around
the late 1990s. Mode 7 used only 1 KB for video RAM by storing each
character as its
ASCII code, rather than its bitmap image as was
needed for the other modes.
Modes 0 to 6 (the '
ASCII ' modes) could display colours from a
logical palette of sixteen: the eight basic colours at the vertices of
RGB colour cube and eight flashing colours made by alternating the
basic colour with its inverse. The palette could be freely
reprogrammed without touching display memory. Modes 3 and 6 were
special text-only modes that used less RAM by reducing the number of
text rows and inserting blank scan lines below each row. Mode 6 was
the smallest, allocating 8 KB as video memory. Modes 0 to 6 could show
diacritics and other user defined characters. All modes except 7
supported bitmapped graphics , but graphics commands such as DRAW and
PLOT had no effect in the text-only modes.
BBC B+ and the later Master provided 'shadow modes', where the
1–20 KB frame buffer was stored in an alternative RAM bank, freeing
the main memory for user programs. This feature was requested by
setting bit 7 of the mode variable, i.e. by requesting modes
80 × 32
640 × 256
40 × 32
320 × 256
20 × 32
160 × 256
80 × 25
640 × 200
40 × 32
320 × 256
20 × 32
160 × 256
40 × 25
320 × 200
40 × 25
480 × 500
A speech synthesis upgrade based on the
Texas Instruments TMS5220
featured sampled phonemes spoken by
Kenneth Kendall .
The speech system was standard on the US model where it had an
American vocabulary. Elsewhere it sold poorly and was eventually
largely replaced by
Superior Software 's software-based synthesiser
using the standard sound hardware.
The speech upgrade also added two empty sockets next to the keyboard
intended to take 16 KB serial ROM cartridges containing either extra
speech phoneme data (in addition to the default speech ROM fitted to
the motherboard), or general software accessed through the ROM Filing
System. The original plan was that some games would be released on
cartridges, but due to the limited sales of the speech upgrade, little
or no software was ever produced for these sockets. The cut-out space
next to the keyboard (nicknamed the "ashtray") was more commonly used
to install other upgrades, such as a ZIF socket for conventional paged
USE IN THE ENTERTAINMENT INDUSTRY
BBC Domesday Project
BBC Domesday Project , a pioneering multimedia experiment, was
based on a modified version of the
BBC Micro's successor, the BBC
Vince Clarke of the British synth pop bands
Depeche Mode ,
Yazoo , and
Erasure used a
BBC Micro (and later a
BBC Master ) with
the UMI music sequencer to compose many hits. In music videos from
the 1980s featuring Vince Clarke, a
BBC Micro is often present or
provides text and graphics such as a clip for Erasure's "Oh L'Amour".
The musical group Queen used the UMI Music Sequencer on their record A
Kind of Magic . The UMI is also mentioned in the CD booklet. Other
bands who have used the Beeb for making music are
A-ha and the reggae
Steel Pulse . Paul Ridout is credited as "UMI programmer" on Cars
Benjamin Orr 's 1986 solo album, The Lace . Black
Uhuru used the Envelope Generator from SYSTEM software (Sheffield)
running on a
BBC Micro, to create some of the electro-dub sounds on
Try It (Anthem album 1983).
BBC Micro was used extensively to provide graphics and sound
effects for many early 1980s
BBC TV shows. These included, notably,
series 3 and 4 of
The Adventure Game ; the children's quiz game
"First Class" (where the onscreen scoreboard was provided by a BBC
Micro nicknamed "Eugene"); and numerous 1980s episodes of Doctor Who
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The Five Doctors ", and "The Twin Dilemma
* 1980s portal
BBC Computer Literacy Project 2012
Micro Bit – modern successor to the project
Micro Men -
BBC documentary drama
Micro Live –
BBC television programme
Making the Most of the Micro –
BBC television programme
BEEBUG – user group magazine
The Micro User (also known as Acorn Computing)
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Watford Electronics 32K Ram Board Manual
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depend to some significant extent on this information. I wrote the
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