BBC Cheese Wedge
Encyclopedia
Second processors
The Second Processors connected to Acorn's proprietary and trademarked Tube interfaceTube (BBC Micro)
In computing, the Tube was the expansion interface and architecture of the BBC Microcomputer System which allowed the BBC Micro to communicate with a second processor, or coprocessor....
. Only one second processor could be connected at a time. The terminology of second processor was slightly misleading, since connected and switched on, the system worked on a "master-slave" model, with the processor in the external unit taking control while the 6502 in the "main" computer simply took on responsibility for I/O
I/O
I/O may refer to:* Input/output, a system of communication for information processing systems* Input-output model, an economic model of flow prediction between sectors...
.
6502 Second Processor
The 6502 Second Processor (using a 65C02) was clocked at 3 MHz, a full 50% faster than the 6502 inside a BBC Model B, and also had 64kB of RAMRam
-Animals:*Ram, an uncastrated male sheep*Ram cichlid, a species of freshwater fish endemic to Colombia and Venezuela-Military:*Battering ram*Ramming, a military tactic in which one vehicle runs into another...
, of which typically 30–44kB was free for application data (compared to as little as 8½kB on an unexpanded Model B in graphics mode, or even less with the disc interface).
Z80 Second Processor
The Z80Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...
Second Processor required the floppy disc upgrade: it was aimed at business and enabled the BBC system to run CP/M
CP/M
CP/M was a mass-market operating system created for Intel 8080/85 based microcomputers by Gary Kildall of Digital Research, Inc...
programs. It ran at 6 MHz and had 64kB of RAM.
32016 Second Processor
A sophisticated Second Processor sometimes branded as "Acorn Cambridge Co-Processor" with an Acorn logo, and sometimes as "BBC Microcomputer System 32016 Second Processor" along with the BBC Micro's owl logo. The device uses the National Semiconductor 32016 CPU and National Semiconductor 32081 FPU running at 6 MHz. It runs the non-graphical Panos operating systemOperating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
. Various programming languages are available including C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
, FORTRAN
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
, Lisp, and Pascal
Pascal (programming language)
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...
, in addition to a version of BBC BASIC
BBC BASIC
BBC BASIC is a programming language, developed in 1981 as a native programming language for the MOS Technology 6502 based Acorn BBC Micro home/personal computer, mainly by Sophie Wilson. It is a version of the BASIC programming language adapted for a U.K...
. The processor comes with 1MB of RAM as standard.
The processor is also inside the Acorn Cambridge Workstation this time using 10 MHz parts and 4MB of RAM, sold as part of the Acorn Business Computer
Acorn Business Computer
The Acorn Business Computer was a series of microcomputers announced at the end of 1983 by the British company Acorn Computers. The series of eight computers was aimed at the business, research and further education markets. However, the ABC range was cancelled before any of the models were...
line.
Universal Second Processor Unit
The Universal Second Processor Unit was an adapter for BBC Master internal co-processor boards, to allow them to be used as external co-processors. It comprised a power supply, interface logic and a connector that matched the internal co-processor connector built into the BBC Master main board. This allowed the BBC B and B+ to use the Turbo board (4 MHz 65C102 with 64kB of RAM) and the Master 512 board (10 MHz 80186 with 512kB of RAM), by fitting them into this expansion unit. It also allowed the BBC Master to have two internal co-processor boards connected, only one of which could be enabled through software.ARM Evaluation System
One of the first production RISC processors the ARMARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
Evaluation System was part of the development programme leading to the Acorn Archimedes
Acorn Archimedes
The Acorn Archimedes was Acorn Computers Ltd's first general purpose home computer to be based on their own ARM architecture.Using a RISC design with a 32-bit CPU, at its launch in June 1987, the Archimedes was stated as running at 4 MIPS, with a claim of 18 MIPS during tests.The name is commonly...
and its early Arthur operating system. It was not branded "BBC" but is physically contained within the family's "cheese wedge" case. The ARM 1 processor was clocked at 8 MHz, and was fitted with 2MB or 4MB of RAM.
In 2006 a new ARM processor board using an ARM7TDMI processor was designed and sold, without an enclosure but able to fit within the original case.
Adapters
The adapters connected to the BBC Micro's 1 MHz bus interface. Adapters could be daisy-chainDaisy chain (electrical engineering)
In electrical and electronic engineering a daisy chain is a wiring scheme in which multiple devices are wired together in sequence or in a ring...
ed, allowing more than one to be fitted.
Teletext Adapter
The teletextTeletext
Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...
-like "Mode 7" display mode inside the 8-bit BBC Micros made a broadcast teletext adapter an obvious expansion, and the BBC would broadcast telesoftware
Telesoftware
The word Telesoftware was coined by W J G Overington who first proposed the idea; it literally means “software at a distance” and it refers to the transmission of programs for a microprocessor or home computers via broadcast Teletext...
free over Ceefax
Ceefax
Ceefax is the BBC's teletext information service transmitted via the analogue signal, started in 1974 and will run until April 2012 for Pages from Ceefax, while the actual interactive service will run until 24 October 2012, in-line with the digital switchover.-History:During the late 60s, engineer...
. The initial software to use the adapter was quite basic but the BBC decided to rewrite it and produced the Advanced Teletext System. This new ROM added several new features including support for the new Fastext system, which introduced the four coloured buttons subsequently found almost ubiquitously on European remote controls, including the "red button" which remains a feature of digital television broadcasting.
Prestel Adapter
The PrestelPrestel
Prestel , the brand name for the UK Post Office's Viewdata technology, was an interactive videotex system developed during the late 1970s and commercially launched in 1979...
adapter was essentially a modem
Modem
A modem is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data...
fitted into the "cheese wedge"-shaped case. It enabled the user to connect to Prestel viewdata
Viewdata
Viewdata is a Videotex implementation. It is a type of information retrieval service in which a subscriber can access a remote database via a common carrier channel, request data and receive requested data on a video display over a separate channel. Samuel Fedida was credited as inventor of the...
services over a telephone line.
IEEE 488 Interface
Allowed the BBC Micro to talk over an IEEE 488 bus to specialised equipment. "Acorn" rather than "BBC" branded.Econet Bridge
Used to connect two EconetEconet
Econet was Acorn's low-cost local area network system, intended for use by schools and small businesses. Econet is rumoured to be an abbreviation of Economy Network, but Acorn were always careful to stress the Greek root, oikos, meaning "house"....
segments together. An Econet Bridge is capable of automatically learning a simple network topology and selectively forwarding packets from one LAN segment to the other using a simple routing table based on the contents of the network byte in the Econet packet.
The Econet Bridge is unique among the cheese wedge expansions, in that it is a stand-alone device that does not require a BBC computer to operate.
General
32016
- Binary Dinosaurs 32016 co-processor
- BeebMaster's 32016
- Acorn Cambridge Co-Processor @ The Centre for Computing History