A system on a module (SoM) is a board-level circuit that integrates a system function in a single module. It may integrate digital and analog functions on a single board. A typical application is in the area of embedded systems
An embedded system is a specialized computer system—a combination of a computer processor, computer memory, and input/output peripheral devices—that has a dedicated function within a larger mechanical or electronic system. It is em ...
. Unlike a single-board computer
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 demonst ...
, a SoM serves a special function like a system on a chip
A system on a chip (SoC) is an integrated circuit that combines most or all key components of a computer or Electronics, electronic system onto a single microchip. Typically, an SoC includes a central processing unit (CPU) with computer memory, ...
(SoC). The devices integrated in the SoM typically requires a high level of interconnection for reasons such as speed, timing, bus width, etc. There are benefits in building a SoM, as for SoC; one notable result is to reduce the cost of the base board or the main PCB. Two other major advantages of SoMs are design-reuse and that they can be integrated into many embedded computer applications.
History
The acronym ''SoM'' has its roots in the blade-based modules. In the mid 1980s, whenVMEbus
VMEbus (Versa Module Eurocard bus) is a computer bus standard physically based on Eurocard sizes.
History
In 1979, during development of the Motorola 68000 CPU, one of their engineers, Jack Kister, decided to set about creating a standar ...
blades used M-Modules, these were commonly referred to as system On a module (SoM). These SoMs performed specific functions such as compute functions and data acquisition functions. SoMs were used extensively by Sun Microsystems
Sun Microsystems, Inc., often known as Sun for short, was an American technology company that existed from 1982 to 2010 which developed and sold computers, computer components, software, and information technology services. Sun contributed sig ...
, Motorola
Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois. It was founded by brothers Paul and Joseph Galvin in 1928 and had been named Motorola since 1947. Many of Motorola's products had been ...
, Xerox
Xerox Holdings Corporation (, ) is an American corporation that sells print and electronic document, digital document products and services in more than 160 countries. Xerox was the pioneer of the photocopier market, beginning with the introduc ...
, DEC, and IBM
International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...
in their blade computers.
Design
A typical SoM consists of: * at least onemicrocontroller
A microcontroller (MC, uC, or μC) or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Pro ...
, microprocessor
A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...
or digital signal processor
A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on metal–oxide–semiconductor (MOS) integrated circuit chips. ...
(DSP) core
** multiprocessor systems-on-chip (MPSoCs) have more than one processor core
* memory
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembe ...
blocks including a selection of ROM
Rom, or ROM may refer to:
Biomechanics and medicine
* Risk of mortality, a medical classification to estimate the likelihood of death for a patient
* Rupture of membranes, a term used during pregnancy to describe a rupture of the amniotic sac
* ...
, RAM
Ram, ram, or RAM most commonly refers to:
* A male sheep
* Random-access memory, computer memory
* Ram Trucks, US, since 2009
** List of vehicles named Dodge Ram, trucks and vans
** Ram Pickup, produced by Ram Trucks
Ram, ram, or RAM may also ref ...
, EEPROM
EEPROM or E2PROM (electrically erasable programmable read-only memory) is a type of non-volatile memory. It is used in computers, usually integrated in microcontrollers such as smart cards and remote keyless systems, or as a separate chip d ...
and/or flash memory
Flash memory is an Integrated circuit, electronic Non-volatile memory, non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for t ...
* timing sources
* industry standard communication
Communication is commonly defined as the transmission of information. Its precise definition is disputed and there are disagreements about whether Intention, unintentional or failed transmissions are included and whether communication not onl ...
interfaces such as USB
Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical ...
, FireWire
IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony a ...
, Ethernet
Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
, USART, SPI, I²C
I2C (Inter-Integrated Circuit; pronounced as "" or ""), alternatively known as I2C and IIC, is a synchronous, multi-master/multi-slave, single-ended, serial communication bus invented in 1980 by Philips Semiconductors (now NXP Semiconduct ...
* peripherals including counter-timers, real-time timer
A timer or countdown timer is a type of clock that starts from a specified time duration and stops upon reaching 00:00. It can also usually be stopped manually before the whole duration has elapsed. An example of a simple timer is an hourglass ...
s and power-on reset
A power-on reset (PoR, POR) generator is a microcontroller or microprocessor peripheral that generates a reset signal when power is applied to the device. It ensures that the device starts operating in a known state.
PoR generator
In VLSI d ...
generators
* analog interfaces including analog-to-digital converter
In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a Digital signal (signal processing), digi ...
s and digital-to-analog converter
In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function.
DACs are commonly used in musi ...
s
* voltage regulator
A voltage regulator is a system designed to automatically maintain a constant voltage. It may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism or electronic components. Depending on the ...
s and power management
Power management is a feature of some electrical appliances, especially copiers, computers, computer CPUs, computer GPUs and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power ...
circuits
See also
* * * * *References
*ANSI
The American National Standards Institute (ANSI ) is a private nonprofit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organiz ...
/IEEE Std 1014-1987 and ANSI/VITA 1-1994
1386-2001 - IEEE Standard for a Common Mezzanine Card Family: CMC
* Standard ANSI/VITA 46.0-2007
VITA Technologies Hall of Fame - PCI Mezzanine Cards
{{refend Microcomputers Embedded systems Computer buses IEEE standards