Single-board computer

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The Raspberry Pi (Model 2B shown) is a low-cost single-board computer often used to teach computer science. Raspberry-Pi-2-Bare-BR.jpg
The Raspberry Pi (Model 2B shown) is a low-cost single-board computer often used to teach computer science.

A single-board computer (SBC) is a complete computer built on a single circuit board, with microprocessor(s), memory, input/output (I/O) and other features required of a functional computer. Single-board computers are commonly made as demonstration or development systems, for educational systems, or for use as embedded computer controllers. Many types of home computers or portable computers integrate all their functions onto a single printed circuit board.

Contents

Unlike a desktop personal computer, single board computers often do not rely on expansion slots for peripheral functions or expansion. Single board computers have been built using a wide range of microprocessors. Simple designs, such as those built by computer hobbyists, often use static RAM and low-cost 32- or 64-bit processors like ARM. Other types, such as blade servers, would perform similar to a server computer, only in a more compact format.

A computer-on-module is a type of single-board computer made to plug into a carrier board, baseboard, or backplane for system expansion. [2] [3]

History

An early MMD-1, the world's first true single board computer, with most chips removed Early 1976 MMD1 Prototype most chips removed.JPG
An early MMD-1, the world's first true single board computer, with most chips removed

The first true single-board computer was based on the Intel C8080A, also using Intel's first EPROM, the C1702A. Schematics for the machine, called the "dyna-micro" were published in Radio-Electronics magazine in May 1976. Later that year, production of the system began by E&L Instruments, a Derby, Connecticut based computer manufacturer, which branded the system as the "Mini Micro Designer 1", intending it for use as a programmable microcontroller for prototyping electronic products. [4] [5] The MMD-1 was made famous as an example microcomputer in popular 8080 instruction series of the time. [6]

Early SBCs figured heavily in the early history of home computers, such as the Acorn Electron and the BBC Micro, also developed by Acorn. Other typical early single board computers like the KIM-1 were often shipped without enclosure, which had to be added by the owner. Other early examples are the Ferguson Big Board, the Ampro Little Board, [7] and the Nascom. Many home computers in the 1980s were single-board computers, with some even encouraging owners to solder upgraded components directly to pre-marked points on the board.

As the PC became more prevalent, SBCs decreased in market share due to their low extensibility. The rapid adoption of IBM's standards for peripherals and the standardization of the PCI bus in the 1990s made motherboards and compatible components and peripherals cheap and ubiquitous, while the development of multimedia platforms such as the CD-ROM and Sound Blaster cards had begun to fast outpace the rate at which users needed to replace their personal computers. These two trends disincentivized single-board computers, and instead encouraged the proliferation of motherboards, which typically housed the CPU and other core components, with peripheral components such as hard disk drive controllers and graphics processors, and even some core components such as RAM modules, located on daughterboards.

Computers began to move back towards fewer boards in the 2000s. As new standards like USB dramatically reduced the variety of peripheral standards motherboards were expected to support, advances in integrated circuit manufacturing provided new chipsets which could provide the functionality of many daughterboards, particularly I/O, in a single chip. By the end of the decade, PC motherboards offered on-board support for disk drives including IDE, SATA, NVMe, RAID, integrated GPU, Ethernet, and traditional I/O such as serial port and parallel port, USB, and keyboard/mouse support. Plug-in "cards" retained their importance as high performance components, such as physically large and complex graphics coprocessors, high-end RAID controllers, and specialized I/O cards such as data acquisition and DSP boards.

The 2010s were defined by rapid and sustained growth in single-board computers, enabled largely by advances in integrated circuit production techniques that made it possible for the first time to include most or all of the core components of a motherboard on a single integrated circuit die. One of the more well known single-board-computers of the decade was the Raspberry Pi, which was built around a custom Broadcom SoC with open-source drivers. Originally intended for education, the Raspberry Pi contained a number of features, such as optimized Linux support and programmable GPIO pins, that were also greatly appealing to hobbyists, who used the Pi, and other comparable SBCs, for projects such as home automation, video game emulation, media streaming, and other experimentation. [8] In industry, the rapid growth of smartphones and other small-scale devices encouraged hardware manufacturers to move towards more frequent use of SoCs and the reduction of motherboards in size, extensibility and complexity, while the proliferation of the Internet of Things increased demand for small, cheap components that would allow unconventional devices to access the Internet. Both of these factors dramatically increased production of single-board computers throughout the decade.

By the end of the 2010s and the early 2020s, many devices, including smartphones, tablet computers, laptops and other smart devices, are powered by single-board computers which utilize advanced SoCs (System on a Chip). While this has greatly increased performance and power efficiency, it has raised concerns that single-board computers, particularly those built around SoCs, are harder to repair and may be less friendly to attempts to monitor or modify instructions programmed into the boards by manufacturers. [9]

Applications

A socket 3 based 486 SBC with power supply and flatscreen Densitron SBC all.JPG
A socket 3 based 486 SBC with power supply and flatscreen

Single board computers were made possible by increasing the density of integrated circuits. A single-board configuration reduces a system's overall cost, by reducing the number of circuit boards required, and by eliminating connectors and bus driver circuits that would otherwise be used. By putting all the functions on one board, a smaller overall system can be obtained, for example, as in notebook computers. Connectors are a frequent source of reliability problems, so a single-board system eliminates these problems. [10]

Single board computers are now commonly defined across two distinct architectures: no slots and slot support.

Embedded 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 automation. Embedded SBCs are much smaller than the ATX-type motherboard 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 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 within other devices to provide control and interfacing. They are used in deep-sea exploration on the ALICE deep sea probes and in outer space, on the Ariane and Pegasus rockets and Space Shuttle. [11] 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. [12]

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 are a market niche and are manufactured less often and at a higher cost. Motherboards and SBCs now offer similar levels of feature integration meaning that a motherboard failure in either standard will require equivalent replacement

Types, standards

Ranges of single-board computers include Raspberry Pi, BeagleBoard and Nano Pi. [13] [14] [15]

One common variety of single board computer uses standardized computer form factors intended for use in a backplane enclosure. Some of these types are CompactPCI, PXI, VMEbus, VXI, and PICMG. SBCs have been built around various internal processing structures including the Intel architecture, multiprocessing architectures, and lower power processing systems like RISC and SPARC. 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 result is similar to having a system built with a motherboard, except that the backplane determines the slot configuration. Backplanes are available with a mix of slots (ISA, PCI, PCI-X, PCI-Express, etc.), usually totaling 20 or fewer, meaning it will fit in a 19" rackmount enclosure (17" wide chassis).

Some single-board computers have connectors that allow a stack of circuit boards, each containing expansion hardware, to be assembled without a traditional backplane. Examples of stacking SBC form factors include PC/104, PC/104-Plus, PCI-104, EPIC, and EBX; these systems are commonly available for use in embedded control systems.

Stack-type SBCs often have memory provided on plug-cards such as SIMMs and DIMMs. 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

See also

Related Research Articles

<span class="mw-page-title-main">Backplane</span> Group of electrical connectors specifically aligned

A backplane or backplane system is a group of electrical connectors 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 to connect several printed circuit boards together to make up a complete computer system. Backplanes commonly use a printed circuit board, but wire-wrapped backplanes have also been used in minicomputers and high-reliability applications.

<span class="mw-page-title-main">Industry Standard Architecture</span> Internal expansion bus in early PC compatibles

Industry Standard Architecture (ISA) is the 16-bit internal bus of IBM PC/AT and similar computers based on the Intel 80286 and its immediate successors during the 1980s. The bus was (largely) backward compatible with the 8-bit bus of the 8088-based IBM PC, including the IBM PC/XT as well as IBM PC compatibles.

<span class="mw-page-title-main">Motherboard</span> Main printed circuit board (PCB) for a computing device

A motherboard is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems, such as the central processor, the chipset's input/output and memory controllers, interface connectors, and other components integrated for general use.

<span class="mw-page-title-main">VESA Local Bus</span> Expansion bus for 486 PCs

The VESA Local Bus is a short-lived expansion bus introduced during the i486 generation of x86 IBM-compatible personal computers. Created by VESA, the VESA Local Bus worked alongside the then-dominant ISA bus to provide a standardized high-speed conduit intended primarily to accelerate video (graphics) operations. VLB provides a standardized fast path that add-in (video) card makers could tap for greatly accelerated memory-mapped I/O and DMA, while still using the familiar ISA bus to handle basic device duties such as interrupts and port-mapped I/O. Some high-end 386DX motherboards also had a VL-Bus slot.

<span class="mw-page-title-main">Expansion card</span> Circuit board for connecting to a computer system to add functionality

In computing, an expansion card is a printed circuit board that can be inserted into an electrical connector, or expansion slot on a computer's motherboard to add functionality to a computer system. Sometimes the design of the computer's case and motherboard involves placing most of these slots onto a separate, removable card. Typically such cards are referred to as a riser card in part because they project upward from the board and allow expansion cards to be placed above and parallel to the motherboard.

<span class="mw-page-title-main">PCI Express</span> Computer expansion bus standard

PCI Express, officially abbreviated as PCIe or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common motherboard interface for personal computers' graphics cards, sound cards, hard disk drive host adapters, SSDs, Wi-Fi and Ethernet hardware connections. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism, and native hot-swap functionality. More recent revisions of the PCIe standard provide hardware support for I/O virtualization.

In computing, a plug and play (PnP) device or computer bus is one with a specification that facilitates the recognition of a hardware component in a system without the need for physical device configuration or user intervention in resolving resource conflicts. The term "plug and play" has since been expanded to a wide variety of applications to which the same lack of user setup applies.

<span class="mw-page-title-main">Chipset</span> Electronic component to manage data flow of a CPU

In a computer system, a chipset is a set of electronic components on one or more integrated circuits that manages the data flow between the processor, memory and peripherals. The chipset is usually found on the motherboard of computers. Chipsets are usually designed to work with a specific family of microprocessors. Because it controls communications between the processor and external devices, the chipset plays a crucial role in determining system performance.

<span class="mw-page-title-main">Mini-ITX</span> 17 × 17 cm motherboard

Mini-ITX is a 170 mm × 170 mm motherboard form factor developed by VIA Technologies in 2001. Mini-ITX motherboards have been traditionally used in small-configured computer systems. Originally, Mini-ITX was a niche standard designed for fanless cooling with a low power consumption architecture, which made them useful for home theater PC systems, where fan noise can detract from the cinema experience.

<span class="mw-page-title-main">PC/104</span> Computer standard family

PC/104 is a family of embedded computer standards which define both form factors and computer buses by the PC/104 Consortium. Its name derives from the 104 pins on the interboard connector (ISA) in the original PC/104 specification and has been retained in subsequent revisions, despite changes to connectors. PC/104 is intended for specialized environments where a small, rugged computer system is required. The standard is modular, and allows consumers to stack together boards from a variety of COTS manufacturers to produce a customized embedded system.

Released as the expansion bus of the Commodore Amiga 3000 in 1990, the Zorro III computer bus was used to attach peripheral devices to an Amiga motherboard. Designed by Commodore International lead engineer Dave Haynie, the 32-bit Zorro III replaced the 16-bit Zorro II bus used in the Amiga 2000. As with the Zorro II bus, Zorro III allowed for true Plug and Play autodetection wherein devices were dynamically allocated the resources they needed on boot.

In electronic systems a diagnostic board is a specialized device with diagnostic circuitry on a printed circuit board that connects to a computer or other electronic equipment replacing an existing module, or plugging into an expansion card slot.

<span class="mw-page-title-main">CPU card</span>

A CPU card is a printed circuit board (PCB) that contains the central processing unit (CPU) of a computer. CPU cards are specified by CPU clock frequency and bus type as well as other features and applications built into the card.

In computing, the motherboard form factor is the specification of a motherboard – the dimensions, power supply type, location of mounting holes, number of ports on the back panel, etc. Specifically, in the IBM PC compatible industry, standard form factors ensure that parts are interchangeable across competing vendors and generations of technology, while in enterprise computing, form factors ensure that server modules fit into existing rackmount systems. Traditionally, the most significant specification is for that of the motherboard, which generally dictates the overall size of the case. Small form factors have been developed and implemented.

M-Modules are a mezzanine standard mainly used in industrial computers. Being mezzanines, they are always plugged on a carrier printed circuit board (PCB) that supports this format. The modules communicate with their carrier over a dedicated bus, and can have all kinds of special functions.

<span class="mw-page-title-main">Single-board microcontroller</span> Microcontroller built onto a single printed circuit board

A 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: a microprocessor, I/O circuits, a clock generator, RAM, stored program memory and any necessary support ICs. The intention is that the board is immediately useful to an application developer, without requiring them to spend time and effort to develop controller hardware.

CompactPCI Serial is an industrial standard for modular computer systems. It is based on the established PICMG 2.0 CompactPCI standard, which uses the parallel PCI bus for communication among a system's card components. In contrast to this, CompactPCI Serial uses only serial point-to-point connections. CompactPCI Serial was officially adopted by the PCI Industrial Computer Manufacturers Group PICMG as PICMG CPCI-S.0 CompactPCI Serial in March 2011. Its mechanical concept is based on the proven standards of IEEE 1101-1-1998 and IEEE 1101-10-1996. CompactPCI Serial includes different connectors that permit very high data rates. The new technology standard succeeding parallel CompactPCI comprises another specification called PICMG 2.30 CompactPCI PlusIO. This is why CompactPCI Serial and CompactPCI PlusIO as a whole were also called CompactPCI Plus. PICMG's first working title of CompactPCI Serial was CPLUS.0. CompactPCI Serial backplanes and chassis are developed by Schroff, Elmа, and Pixus Technologies companies, as for the CompactPCI Serial board level electronics – they are developed by MEN Mikro Elektronik, Fastwel, EKF, Emerson Embedded Computing, ADLINK, and Kontron.

PICMG 1.0 is a PICMG specification that defines a CPU form factor and corresponding backplane connectors for PCI-ISA passive backplanes. This standard moves components typically located on the motherboard to a single plug-in card. PICMG 1.0 CPU Cards look much like standard ISA cards with extra gold finger connections for the ISA bus and the root PCI bus. The "motherboard" is replaced with a simple "passive backplane" that has only PCI and ISA connectors attached to it. These backplane connections include a dedicated system slot of the PICMG 1.0 CPU and various connections for standard ISA and PCI peripheral cards. This backplane is simple and robust, with a very low likelihood of failure, given its passive nature. This allows a much lower Mean Time to Repair than classic computer motherboard approaches, as electronics associated with CPUs can be replaced without having to remove peripheral devices.

PICOe within computer hardware is a computer form factor in which a half sized card slot Single Board Computer (SBC) is inserted into a gold fingers card slot of a passive or active backplane. Expansion peripherals of the computer system are connected to other slots of the backplane.

N8VEM was a homebrew computing project. It featured a variety of free and open hardware and software. N8VEM builders made their own homebrew computer systems for themselves and shared their experiences with other homebrew computer hobbyists. N8VEM homebrew computer components are made in the style of vintage computers of the mid to late 1970s and early 1980s using a mix of classic and modern technologies. They are designed with ease of amateur assembly in mind.

References

  1. ↑ "Foundation Strategy 2016–2018" (PDF). Raspberry Pi. Raspberry Pi Foundation. pp. 3–5. Archived (PDF) from the original on 9 June 2016. Retrieved 26 November 2016.
  2. ↑ "COM – Based SBCs: The Superior Architecture for Small Form Factor Embedded Systems" (PDF). Diamond Systems Corp. Archived (PDF) from the original on 29 December 2016. Retrieved 27 December 2016.
  3. ↑ "Implementing High Performance Embedded Computing Hardware" (PDF). Trenton Systems, Inc. September 1, 2016. pp. 13–15. Archived (PDF) from the original on 26 November 2016. Retrieved 26 November 2016.
  4. ↑ "E&L Instruments | OpenCorporates". opencorporates.com. Retrieved 2023-03-06.
  5. ↑ "Mini-Micro Designer 1 (MMD1)". www.decodesystems.com. Retrieved 2023-03-06.
  6. ↑ "Virginia Information". www.bugbookcomputermuseum.com. Retrieved 2023-03-06.
  7. ↑ "Ampro Little Board". Archived from the original on 2020-02-07. Retrieved 2020-09-05.
  8. ↑ Cawley, Christian (2019-12-10). "19 Awesome Uses for a Raspberry Pi". MUO. Retrieved 2023-03-06.
  9. ↑ "What You Should Know About Right to Repair". Wirecutter: Reviews for the Real World. 2021-07-15. Retrieved 2023-03-06.
  10. ↑ Winn Rosch, Hardware Bible Fifth Edition, Que, 1999 ISBN   0-7897-1743-3 pp. 50-51
  11. ↑ "Single Board Computer Peripherals". Newmicros. Archived from the original on June 28, 2017. Retrieved July 7, 2017.
  12. ↑ "A UHF RFID Printed Circuit Board Solution". Magicstrap. January 2012. p. 4. Archived from the original on 26 November 2016. Retrieved 26 November 2016.
  13. ↑ updated, Brian Westover last (2021-05-27). "Raspberry Pi 4 Model B review". Tom's Guide. Retrieved 2023-04-29.
  14. ↑ Manager, Content (2023-01-29). "BeagleBone Black Review". ElectronicsHacks. Retrieved 2023-04-29.
  15. ↑ Alderson, Alex. "FriendlyELEC introduces new NanoPi R6C single-board computer for US$89". Notebookcheck. Retrieved 2023-04-29.
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