Single-board computer
Encyclopedia
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
built on a single circuit board, with microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
(s), memory
Ram
-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...
, input/output
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...
(I/O) and other features required of a functional computer. Unlike a typical personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
, an SBC may not include slots
Edge connector
An edge connector is the portion of a printed circuit board consisting of traces leading to the edge of the board that are intended to plug into a matching socket. The edge connector is a money-saving device because it only requires a single discrete female connector , and they also tend to be...
into which accessory cards ("daughterboard
Daughterboard
A daughterboard, daughtercard or piggyback board is a circuit board meant to be an extension or "daughter" of a motherboard , or occasionally of another card...
s") may be plugged. An SBC may be based on almost any available microprocessor, and may be built up from discrete logic or programmable logic. Simple designs, such as built by computer hobbyists, often use static RAM and low-cost eight or 16 bit processors.
History
The first true single-board computer (see the May 1976 issue of Radio-ElectronicsRadio-Electronics
Radio-Electronics was an American electronics magazine that was published under various titles from 1929 to 2003. Hugo Gernsback started it as Radio-Craft in July 1929. The title was changed to Radio-Electronics in October 1948 and again to Electronics Now in July 1992. In January 2000 it was...
) called the "dyna-micro" was based on the Intel C8080
Intel 8080
The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...
A, and also used Intel's first EPROM
EPROM
An EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...
, the C1702A. The dyna-micro was re-branded by E&L Instruments of Derby, CT in 1976 as the "MMD-1" (Mini-Micro Designer 1) and was made famous as the example microcomputer in the very popular 8080 "BugBook" series of the time. SBCs also figured heavily in the early history of home computer
Home computer
Home computers were a class of microcomputers entering the market in 1977, and becoming increasingly common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a single nontechnical user...
s, for example in the Acorn Electron
Acorn Electron
The Acorn Electron is a budget version of the BBC Micro educational/home computer made by Acorn Computers Ltd. It has 32 kilobytes of RAM, and its ROM includes BBC BASIC along with its operating system....
and the BBC Micro
BBC Micro
The BBC Microcomputer System, or BBC Micro, was a series of microcomputers and associated peripherals designed and built by Acorn Computers for the BBC Computer Literacy Project, operated by the British Broadcasting Corporation...
. Other typical early single board computers were often shipped without enclosure
Enclosure (electrical)
An electrical enclosure is a cabinet for electrical or electronic equipment to mount switches, knobs and displays and to prevent electrical shock to equipment users and protect the contents from the environment...
, which had to be added by the owner, examples are the Ferguson Big Board and the Nascom
Nascom
The Nascom 1 and 2 were single-board computer kits issued in 1977 and 1979, respectively, based on the Zilog Z80 and including a keyboard and video interface, a serial port that could be used to store data on a tape cassette using the Kansas City standard, and two 8-bit parallel ports...
.
With the development of PCs there was a sharp shift away from SBC, with computers being constructed from a motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...
, with functions like serial ports, disk drive controller and graphics being provided on daughterboards. The recent availability of advanced chip sets providing most of the I/O features as embedded components allows motherboard manufacturers to offer motherboards with I/O traditionally provided by daughterboards. Most PC motherboards now offer on-board support for disk drives including IDE and SATA
Sata
Sata is a traditional dish from the Malaysian state of Terengganu, consisting of spiced fish meat wrapped in banana leaves and cooked on a grill.It is a type of Malaysian fish cake, or otak-otak...
with RAID
RAID
RAID is a storage technology that combines multiple disk drive components into a logical unit...
, graphics, Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
, and traditional I/O such as serial and parallel ports, USB, and keyboard/mouse support. Plug-in cards are now more commonly high performance graphics cards (really graphic co-processors), high end RAID controllers, and specialized I/O cards such as data acquisition and DSP (Digital Signal Processor) boards.
Applications
Single board computers are now commonly defined across two distinct architectures: no slots and slot support.Embedded
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
SBCs are units providing all the required I/O with no provision for plug-in cards. Applications are typically gaming (slot machines, video poker), kiosk, and machine control. Embedded SBCs are much smaller than the ATX-type motherboard
ATX
ATX is a motherboard form factor specification developed by Intel in 1995 to improve on previous de facto standards like the AT form factor. It was the first big change in computer case, motherboard, and power supply design in many years, improving standardization and interchangeability of parts...
found in PCs, and provide an I/O mix more targeted to an industrial application, such as on-board digital and analog I/O, on-board bootable flash memory (eliminating the need for a disk drive]), no video, etc.
The term "Single Board Computer" now generally applies to an architecture where the Single Board Computer is plugged into a backplane
Backplane
A backplane is a group of connectors connected in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors forming a computer bus. It is used as a backbone to connect several printed circuit boards together to make up a complete...
to provide for I/O cards. In the case of PC104, the bus is not a backplane in the traditional sense but is a series of pin connectors allowing I/O boards to be stacked.
Single board computers are most commonly used in industrial situations where they are used in rackmount format for process control or embedded
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
within other devices to provide control and interfacing. Because of the very high levels of integration, reduced component counts and reduced connector counts, SBCs are often smaller, lighter, more power efficient and more reliable than comparable multi-board computers.
The primary advantage of an ATX motherboard as compared to an SBC is cost. Motherboards are manufactured by the millions for the consumer and office markets allowing tremendous economies of scale. Single Board Computers, on the other hand, are in a specialized market niche and are manufactured in much smaller numbers with the resultant higher cost. Motherboards and SBCs now offer similar levels of feature integration meaning that a motherboard failure in either standard will require equivalent replacement.
The primary advantage of a PICMG Single Board Computer is the availability of backplanes offering virtually any slot configuration including legacy ISA support. Motherboards tend to the latest slot technology such that PCI slots are becoming legacy support with PCI Express
PCI Express
PCI Express , officially abbreviated as PCIe, is a computer expansion card standard designed to replace the older PCI, PCI-X, and AGP bus standards...
becoming the standard. In addition, motherboards offer, at most, 7 slots while backplanes can offer up to 20 slots. In a backplane 12.3" wide, similar in size to an ATX motherboard at 12", a backplane with a Single Board Computer can offer 12 slots for I/O cards with virtually any mix of slot types.
Types, standards
Currently the most common variety of Single Board Computer in use is of a specific form factor similar to other full-size plug-in cards and is intended to be used in a backplaneBackplane
A backplane is a group of connectors connected in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors forming a computer bus. It is used as a backbone to connect several printed circuit boards together to make up a complete...
. Some architectures are dependent entirely on single-board computers, such as CompactPCI
CompactPCI
A CompactPCI system is a 3U or 6U Eurocard-based industrial computer, where all boards are connected via a passive PCI backplane. The connector pin assignments are standardized by the PICMG US and PICMG Europe organizations. PICMG stands for PCI Industrial Computers Manufacturers Group...
, PXI
PXI
PCI eXtensions for Instrumentation is one of several modular electronic instrumentation platforms in current use. These platforms are used as a basis for building electronic test equipment, automation systems, modular laboratory instruments in science, and the like. PXI is based on...
, VMEbus
VMEbus
VMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...
, VXI
VXI
The VXI bus architecture is an open standard platform for automated test based upon VMEbus. VXI stands for VME eXtensions for Instrumentation, defining additional bus lines for timing and triggering as well as mechanical requirements and standard protocols for configuration, message-based...
, PICMG
PICMG
The PCI Industrial Computer Manufacturers Group is a consortium of over 227 companies. The group, founded in 1994, was originally formed to adapt PCI technology for use in high-performance telecommunications, military and industrial computing applications but its work has now grown to include...
architecture, etc. In the Intel PC world, the intelligence and interface/control circuitry is placed on a plug-in board that is then inserted into a passive (or active) backplane. The end result is similar to having a system built with a motherboard
Motherboard
In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...
, except that the backplane determines the slot configuration. Backplanes are available with a mix of slots (ISA, PCI, PCIX, PCI-Express, etc.), usually totaling 20 or fewer, meaning it will fit in a 19" rackmount enclosure (17" wide chassis).
Some single-board computers also exist as form factors that stack like building blocks, and do not have the form of a traditional backplane. Examples of stacking SBC form factors include PC/104
PC/104
PC/104 is an embedded computer standard controlled by the which defines both a form factor and computer bus. PC/104 is intended for specialized embedded computing environments where applications depend on reliable data acquisition despite an often extreme environment...
, PC/104-Plus, PCI-104, EPIC, and EBX; these systems are commonly available for use in embedded control systems.
PICMG
PICMG
The PCI Industrial Computer Manufacturers Group is a consortium of over 227 companies. The group, founded in 1994, was originally formed to adapt PCI technology for use in high-performance telecommunications, military and industrial computing applications but its work has now grown to include...
provides standards for the backplane interface:
PICMG 1.0, 1.1 and 1.2 provide for ISA and PCI support with 1.2 adding PCIX support
PICMG 1.3 provides for PCI-Express support. Single Board Computers meeting the PICMG 1.3 specification are referred to as a System Host Board
System Host Board
thumb|right|300px|PICMG 1.3 SHB and BackplaneSystem Host Board is a term applied to a Single Board Computer meeting the PICMG 1.3 specification. PICMG 1.3 extended the previous PICMG specifications to continue support for PCI/PCI-X plug in cards as well as new support for PCI-Express.- External...
(SHB).
Stack-type SBCs often have memory provided on plug-cards such as SIMM
SIMM
A SIMM, or single in-line memory module, is a type of memory module containing random access memory used in computers from the early 1980s to the late 1990s. It differs from a dual in-line memory module , the most predominant form of memory module today, in that the contacts on a SIMM are redundant...
s and DIMM
DIMM
A DIMM or dual in-line memory module, comprises a series of dynamic random-access memory integrated circuits. These modules are mounted on a printed circuit board and designed for use in personal computers, workstations and servers...
s, however they can still be regarded as SBCs because although the memory modules are technically additional circuit boards, they have no extra functionality beyond providing memory and are basically just carriers for the RAM chips. Hard drive circuit boards are also not counted for determining if a computer is an SBC or not for two reasons, firstly because the HDD is regarded as a single block storage unit, and secondly because the SBC may not require a hard drive at all as most can be booted from their network connections.
Form Factors
- AdvancedTCAAdvanced Telecommunications Computing ArchitectureAdvanced Telecommunications Computing Architecture is the largest specification effort in the history of the PCI Industrial Computer Manufacturers Group , with more than 100 companies participating. Known as AdvancedTCA, the official specification designation PICMG 3.x was ratified by the PICMG...
- CompactPCICompactPCIA CompactPCI system is a 3U or 6U Eurocard-based industrial computer, where all boards are connected via a passive PCI backplane. The connector pin assignments are standardized by the PICMG US and PICMG Europe organizations. PICMG stands for PCI Industrial Computers Manufacturers Group...
- Embedded Compact ExtendedEmbedded Compact ExtendedEmbedded Compact Extended is a small form factor Single Board Computer specification set out by Intel. ECX boards measure 105mm x 146mm....
(ECX) - Micro Tca
- Mini-ITXMini-ITXMini-ITX is a 17 x 17 cm low-power motherboard form factor developed by VIA Technologies in 2001. Mini-ITX is slightly smaller than microATX. Mini-ITX boards can often be passively cooled due to their low power consumption architecture, which makes them useful for home theater PC systems,...
- PC/104PC/104PC/104 is an embedded computer standard controlled by the which defines both a form factor and computer bus. PC/104 is intended for specialized embedded computing environments where applications depend on reliable data acquisition despite an often extreme environment...
- PICMGPICMGThe PCI Industrial Computer Manufacturers Group is a consortium of over 227 companies. The group, founded in 1994, was originally formed to adapt PCI technology for use in high-performance telecommunications, military and industrial computing applications but its work has now grown to include...
- PXIPXIPCI eXtensions for Instrumentation is one of several modular electronic instrumentation platforms in current use. These platforms are used as a basis for building electronic test equipment, automation systems, modular laboratory instruments in science, and the like. PXI is based on...
- VMEbusVMEbusVMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...
- VPXVPXVPX, formerly known as VITA 46, is an ANSI standard that provides VMEbus-based systems with support for switched fabrics over a new high speed connector...
- VXIVXIThe VXI bus architecture is an open standard platform for automated test based upon VMEbus. VXI stands for VME eXtensions for Instrumentation, defining additional bus lines for timing and triggering as well as mechanical requirements and standard protocols for configuration, message-based...
See also
- Single-board microcontrollerSingle-board microcontrollerA single-board microcontroller is a microcontroller built onto a single printed circuit board. This board provides all of the circuitry necessary for a useful control task: microprocessor, I/O circuits, clock generator, RAM, stored program memory and any support ICs necessary...
- ArduinoArduinoArduino is an open-source single-board microcontroller, descendant of the open-source Wiring platform, designed to make the process of using electronics in multidisciplinary projects more accessible. The hardware consists of a simple open hardware design for the Arduino board with an Atmel AVR...
- Apple IApple IThe original Apple Computer, also known retroactively as the Apple I, or Apple-1, is a personal computer released by the Apple Computer Company in 1976. They were designed and hand-built by Steve Wozniak. Wozniak's friend Steve Jobs had the idea of selling the computer...
- BeagleBoard
- ECB AT91
- Embedded systemEmbedded systemAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
- GMC-4GMC-4The GMC-4 is the only 4-bit microcomputer to be mass-produced in the last 30 years. It was produced by Gakken, a Japanese publisher - as a mook. The mook comprised a magazine attached to a box containing the components required to assemble the computer....
- GumstixGumstixGumstix is a company founded in 2003 by Gordon Kruberg that produces small single-board computers. The name Gumstix refers to the size of the first such computer being the approximate size of a stick of gum....
- IGEPv2IGEPv2The IGEPv2 board is a low-power, fanless single-board computer developed and produced by Spanish corporation ISEE and is the second IGEP platform in the series.-Board Specifications:* Package on package Memory/Processor...
- KIM-1KIM-1The KIM-1, short for Keyboard Input Monitor, was a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976...
- N8VEMN8VEMN8VEM is a homebrew computing project. It features a variety of free and open hardware and software. N8VEM builders make their own homebrew computer systems for themselves and share their experiences with other homebrew computer hobbyists...
- P112P112The P112 is a single-board computer carrying a Zilog Z180 microprocessor. It was designed by Dave Brooks in 1996, went out of production, and then brought back in 2004 by David Griffith. It's capable of running CP/M, but usually runs ZSDOS, an enhanced CP/M look-alike.- External links :* * *...
- Raspberry PiRaspberry PiThe Raspberry Pi is a single-board computer developed by the Raspberry Pi Foundation. Scheduled for public release in December 2011, the foundation plans to release two versions that range from US$25 to $35...
- SBC6446