Computer-on-module
Encyclopedia
A computer-on-module (COM) or System on Module (SOM) is a type of single-board computer
(SBC), a subtype of an embedded computer system. An extension of the concept of System on Chip (SoC), COM lies between a full-up computer and a microcontroller
in nature.
with RAM
, input/output
controllers and all other features needed to be a functional computer on the one board. However, unlike a single-board computer, the COM will usually lack the standard connectors for any input/output peripherals to be attached directly to the board.
The module will usually need to be mounted on a carrier board (or "baseboard") which breaks the bus out to standard peripheral connectors. Some COMs also include peripheral connectors and/or can be used without a carrier.
A COM solution offers a dense package computer system for use in small or specialized applications requiring low power consumption or small physical size as is needed in embedded system
s. As a COM is very compact and highly integrated, even complex CPUs, including multi-core technology, can be realized on a COM.
Using a carrier board is a benefit in many cases, as it can implement special I/O interfaces, memory devices, connectors or form factors. Separating the design of the carrier board and COM makes design concepts more modular, if needed. A carrier tailored to a special application may involve high design overhead by itself. If the actual processor and main I/O controllers are located on a COM, it is much easier, for example, to upgrade a CPU component to the next generation, without having to redesign a very specialized carrier as well. This can save costs and shorten development times. On the other hand, this only works if the board-to-board connection between the COM and its carrier remains compatible between upgrades.
Some devices also incorporate Field Programmable Gate Array (FPGA) components. FPGA-based functions can be added as IP cores to the COM itself or to the carrier card. Using FPGA IP cores adds to the modularity of a COM concept, because I/O functions can be adapted to special needs without extensive rewiring on the printed circuit board
.
The term became more notable upon industry standardization of the COM Express
format.
Single-board computer
A single-board computer is a complete computer built on a single circuit board, with microprocessor, memory, input/output and other features required of a functional computer. Unlike a typical personal computer, an SBC may not include slots into which accessory cards may be plugged...
(SBC), a subtype of an embedded computer system. An extension of the concept of System on Chip (SoC), COM lies between a full-up computer and a microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
in nature.
Design
Today's COM modules are complete embedded computers built on a single circuit board. The design is centered on a microprocessorMicroprocessor
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...
with RAM
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...
controllers and all other features needed to be a functional computer on the one board. However, unlike a single-board computer, the COM will usually lack the standard connectors for any input/output peripherals to be attached directly to the board.
The module will usually need to be mounted on a carrier board (or "baseboard") which breaks the bus out to standard peripheral connectors. Some COMs also include peripheral connectors and/or can be used without a carrier.
A COM solution offers a dense package computer system for use in small or specialized applications requiring low power consumption or small physical size as is needed in embedded system
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...
s. As a COM is very compact and highly integrated, even complex CPUs, including multi-core technology, can be realized on a COM.
Using a carrier board is a benefit in many cases, as it can implement special I/O interfaces, memory devices, connectors or form factors. Separating the design of the carrier board and COM makes design concepts more modular, if needed. A carrier tailored to a special application may involve high design overhead by itself. If the actual processor and main I/O controllers are located on a COM, it is much easier, for example, to upgrade a CPU component to the next generation, without having to redesign a very specialized carrier as well. This can save costs and shorten development times. On the other hand, this only works if the board-to-board connection between the COM and its carrier remains compatible between upgrades.
Some devices also incorporate Field Programmable Gate Array (FPGA) components. FPGA-based functions can be added as IP cores to the COM itself or to the carrier card. Using FPGA IP cores adds to the modularity of a COM concept, because I/O functions can be adapted to special needs without extensive rewiring on the printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
.
History
The terms "Computer-on-Module" and "COM" were coined by VDC Research Group, Inc. (formerly Venture Development Corporation) (Natick, MA, USA) to describe this class of embedded computer boards.The term became more notable upon industry standardization of the COM Express
COM Express
COM Express, a computer-on-module form factor, is a highly integrated and compact PC that can be used in a design application much like an integrated circuit component. Each COM Express Module COM integrates core CPU and memory functionality, the common I/O of a PC/AT, USB, audio, graphics , and...
format.
See also
- CoreExpressCoreExpressCoreExpress modules are complete computer-on-module highly integrated, small and compact PCs that can be used in an embedded computer board design, much like an integrated circuit component. COMs integrate CPU, memory, graphics, and BIOS, and common IO interfaces...
- Embedded System ModuleEmbedded System ModuleEmbedded System Module, or ESM, is a compact computer-on-module standard. An ESM module typically includes a CPU processor, memory, module-specific I/O interfaces and a number of basic front I/O connectors...
- ESMexpressESMexpressESMexpress is a very compact computer-on-module standard. It is a complete processor module that currently supports several low-power Intel and PowerPC platforms. Apart from a CPU component, every module also includes memory and a range of serial communication interfaces such as PCI Express,...
- ETX Form Factor
- QsevenQsevenQseven, a computer-on-module form factor, is small sized and highly integrated computer module that can be used in a design application much like an integrated circuit component. It's smaller than other computer-on-module standards such as COM Express, ETX or XTX but is limited to very low power...
- XTXXTXXTX is a computer-on-module standard for x86-based embedded devices. XTX adds PCI-Express, SATA, and LPC capabilities. The standard was promulgated by Advantech, , and congatec.-External links:* *...