SYSTEM-ON-MODULE

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) and system in package (SiP), COM lies between a full-up computer and

a microcontroller in nature.

Today's COM modules are complete embedded computers built on a single circuit board. The

design is centered on a microprocessor 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 inembedded

systems. 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 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 format.

Embedded System Module, or ESM, is a compact computer-on-module (COM) standard. An

ESM module typically includes a CPU processor, memory, module-specific I/O interfaces and a

number of basic front I/O connectors. They can be plugged on a carrier board or be used as a

stand-alone processor card.

If the ESM module is plugged on a carrier, it relies on the standard PCI bus as a board-to-board

interface. In this case two connectors create a link to the carrier. While the "J1" connector

provides a specified PCI connection, the "J2" connector brings I/O signals from the ESM module

to the carrier, which then includes all necessary connectors. The signal assignment of J2 is not

fixed but can be completely customized, although there are reserved pins for a 64-bit PCI bus

interface. A third connector, "J3", is used for additional I/O signals if the ESM module has no

front I/O. The signal assignment of this connector is fixed to support a special set of I/O

functions.

A large part of the I/O functions on ESMs are often controlled by an onboard FPGAcomponent

(field-programmable gate array) so that every module can easily be tailored to a specialized

application through user-defined functions. Such functions are loaded into the FPGA as IP cores.

Using FPGAs also reduces dependence on special controller chips which may become obsolete,

thus extending the card's availability.

ESMs are typically used on boards for CompactPCI and VMEbus as well as single-board

computers for embedded applications. A company standard by MEN Micro, a manufacturer of

embedded computers, specifies the ESM concept and the different types of modules. The ESM

specification defines one form factor for the printed circuit board: 149 × 71 mm (5.9 × 2.8 in).

Depending on the processor type, most ESM modules have heat sinks and can be operated in

wide temperature ranges up to -40 to +85 °C.

A mechanical specialty of ESM modules is that their connectors are compatible with the  PCI-

104 module standard. These modules can be "stacked" onto ESM modules, e. g., for additional

peripheral interfaces.

SOM2416-II-440

SOM3530

SOM3517

e-con Systems, eSOM3730 Computer-on-Module

DHCOM Computer On Module with AM35x Processor, DH electronics

Toradex Colibri T30 Computer On Module

Gumstix Overo COM, a tiny, OMAP-based COM

SOM, OMAP / Marvell / Cortex-A8-based COM

Variscite's SOMs are complete computers built on a single circuit board. The design is centered

on a single microprocessor 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

module will usually lack the standard connectors for any input/output peripherals to be attached

directly to the board. Instead, the wiring for these peripherals are bussed out to connectors on the

board.

The SOM requires to be mounted on a carrier board (or "baseboard") which breaks the bus out to

standard peripheral connectors. Variscite's SOMs offer 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 systems

Variscite's SOMs are low-power, high performance System-on-Modules which serve as building

blocks and easily integrate into any embedded solution. They include an extensive range of

interfaces and communication protocols and are ready to run any embedded operating system

such as Linux and Windows Embedded CE

Variscite SOMs are widely used in a variety of industrial fields such as: Medical, Agriculture,

Industrial computing, Military and consumer products.

Typical SOM block diagram:

Variscite's latest and recommended SOMs:

DART-4460 –Texas Instruments OMAP4460 based on OMAP4460, 1.5GHz Dual-Core Cortex-

A9.Thefastest ARM System on Module on the market today.

The DART-4460, offers an ideal solution for a wide range of applications which require

rich multimedia functionality as well as high-processing power. This compact, cost effective and

low consumption SoM offers a performance level of an Intel Atom.

VAR-SOM-OM44 - Texas Instruments OMAP4460

based on OMAP4460, 1.5GHz Dual-Core Cortex-A9. The fastest ARM System on Module on

the market today. The VAR-SOM-OM44, offers an ideal solution for a wide range of

applications which require rich multimedia functionality as well as high-processing power. This

compact, cost effective and low consumption SoM offers a performance level of an Intel Atom.

VAR-SOM-MX6 - Supporting the i.MX 6 Quad/Dual/DualLite/Single, the VAR-SOM-MX6

allows designers to use a single System on Module in a broad range of applications to achieve

short time-to-market for their current innovations, while still accommodating potential R&D

directions and marketing opportunities. This versatile solution’s -40 to 85 °C temperature range

and Dual CAN support is ideal for industrial applications, while 1080p video and graphics

accelerations make it equally suitable for intensive multimedia applications.

VAR-SOM-AM33 - Texas Instruments AM335X based System-on-Module. Recommended for

low cost designs. 

VAR-SOM-OM37 - Texas Instruments AM3703 / DM3730 based System-on-Module

The VAR-SOM-OM37 is a low-power, high performance System-on-module which serves as a

building block and easily integrates into any embedded solution. It includes an extensive range

of interfaces and communication protocols and is ready to run any embedded operating system

such as Linux and Windows Embedded CE.

VAR-SOM-AM35 - Texas Instruments AM3505 / AM3517 based System-on-Module.

Recommended for industrial applications.

VAR-SOM-MX25 - Freescale i.MX25based System-on-Module

The VAR-SOM-MX25 is a cost optimized, highly integrated, low-power System-On-Module

which serves as a building block and easily integrates into any embedded solution. It includes all

vital peripherals / interfaces and is ready to run any embedded operating system such as Linux,

Windows Embedded CE.

VAR-SOM-OM35 - Texas Instruments OMAP3530 based System-on-Module

The VAR-SOM-OM35 is a low-power, high performance System-on-module which serves as a

building block and easily integrates into any embedded solution. It includes an extensive range

of interfaces and communication protocols and is ready to run any embedded operating system

such as Linux and Windows Embedded CE.

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 were made as demonstration or development systems, for

educational systems, or for use as embedded computer controllers. Many types of home

computer or portable computer integrated all their functions onto a single printed circuit board.

Unlike a desktop personal computer, single board computers often did not rely on expansion

slots for peripheral functions or expansion. Some single-board computers are made to plug into

a backplane for system expansion. Single board computers have been built using a wide range of

microprocessors. Simple designs, such as built by computer hobbyists, often use static RAM and

low-cost eight or 16 bit processors. Other types, such as blade servers, include all the memory

and processor performance of a server computer in a compact space-saving format.

Single board computers were made possible by increasing 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.[1]

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.

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 ofPC104, 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. 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 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.[

An embedded system is a computer system with a dedicated function within a larger mechanical

or electrical system, often with real-time computing constraints.[1][2] 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 computer (PC), is designed to be flexible and to meet a wide range

of end-user needs. Embedded systems control many devices in common use today.[3]

Modern embedded systems are often based on microcontrollers (i.e CPUs with integrated

memory and/or peripheral interfaces)[4] but ordinary microprocessors (using external chips for

memory and peripheral interface circuits) are also still common, especially in more complex

systems. In either case, the processor(s) used may be types ranging from rather general purpose

to very specialised in certain class of computations, or even custom designed for the application

at hand. A common standard class of dedicated processors is the digital signal processor (DSP).

The key characteristic, however, is being dedicated to handle a particular task. Since the

embedded system is dedicated to specific tasks, design engineers can optimize it to reduce the

size and cost of the product and increase the reliability and performance. Some embedded

systems are mass-produced, benefiting from economies of scale.

Physically, embedded systems range from portable devices such as digital watches and MP3

players, to large stationary installations like traffic lights, factory controllers, and largely

complex systems like hybrid vehicles, MRI, and avionics. Complexity varies from low, with a

single microcontroller chip, to very high with multiple units, peripherals and networks mounted

inside a large chassis or enclosure.

Embedded systems are commonly found in consumer, cooking, industrial, automotive, medical,

commercial and military applications.

Telecommunications systems employ numerous embedded systems from telephone switches for

the network to cell phones at the end-user. Computer networking uses

dedicated routers and network bridges to route data.

Consumer electronics include personal digital assistants (PDAs), mp3 players, mobile

phones, videogame consoles, digital cameras,DVD players, GPS receivers, and printers. Many

household appliances, such as microwave ovens, washing machines and dishwashers, include

embedded systems to provide flexibility, efficiency and features. Advanced HVAC systems use

networked thermostats to more accurately and efficiently control temperature that can change by

time of day and season. Home automation uses wired- and wireless-networking that can be used

to control lights, climate, security, audio/visual, surveillance, etc., all of which use embedded

devices for sensing and controlling.

Transportation systems from flight to automobiles increasingly use embedded systems. New

airplanes contain advanced avionics such as inertial guidance systems and GPS receivers that

also have considerable safety requirements. Various electric motors — brushless DC

motors, induction motors and DC motors — use electric/electronic motor

controllers. Automobiles, electric vehicles, and hybrid vehicles increasingly use embedded

systems to maximize efficiency and reduce pollution. Other automotive safety systems

include anti-lock braking system (ABS), Electronic Stability Control (ESC/ESP), traction

control (TCS) and automatic four-wheel drive.

Medical equipment uses embedded systems for vital signs monitoring, electronic

stethoscopes for amplifying sounds, and various medical imaging (PET, SPECT, CT, MRI) for

non-invasive internal inspections. Embedded systems within medical equipment are often

powered by industrial computers.[6] Embedded systems are used in transportation, fire safety,

safety and security, medical applications and life critical systems, as these systems can be

isolated from hacking and thus, be more reliable.[citation needed] For fire safety, the systems can be

designed to have greater ability to handle higher temperatures and continue to operate. In dealing

with security, the embedded systems can be self-sufficient and be able to deal with cut electrical

and communication systems.

A new class of miniature wireless devices called motes are quickly gaining popularity as the

field of wireless sensor networking is increasing. Wireless sensor networking, WSN, makes use

of miniaturization made possible by advanced IC design to couple full wireless subsystems to

sophisticated sensors, enabling people and companies to measure a myriad of things in the

physical world and act on this information through IT monitoring and control systems. These

motes are completely self-contained, and will typically run of a battery source for many years

before the batteries need to be changed or charged.

Embedded Wi-Fi modules provide a simple means of wirelessly enabling any device which

communicates via a serial port.

A system on a chip or system on chip (SoC or SOC) is an integrated circuit (IC) that integrates

all components of a computer or otherelectronic system into a single chip. It may

contain digital, analog, mixed-signal, and often radio-frequency functions—all on a single

chipsubstrate. A typical application is in the area of embedded systems.

The contrast with a microcontroller is one of degree. Microcontrollers typically have under

100 kB of RAM (often just a few kilobytes) and often really are single-chip-systems, whereas

the term SoC is typically used for more powerful processors, capable of running software such as

the desktop versions of Windows and Linux, which need external memory chips (flash, RAM) to

be useful, and which are used with various external peripherals. In short, for larger systems, the

term system on a chip is a hyperbole, indicating technical direction more than reality: increasing

chip integration to reduce manufacturing costs and to enable smaller systems. Many interesting

systems are too complex to fit on just one chip built with a process optimized for just one of the

system's tasks.

When it is not feasible to construct a SoC for a particular application, an alternative is a system

in package (SiP) comprising a number of chips in a single package. In large volumes, SoC is

believed to be more cost-effective than SiP since it increases the yield of the fabrication and

because its packaging is simpler.[1]

Another option, as seen for example in higher end cell phones and on the BeagleBoard,

is package on package stacking during board assembly. The SoC chip includes processors and

numerous digital peripherals, and comes in a ball grid package with lower and upper

connections. The lower balls connect to the board and various peripherals, with the upper balls in

a ring holding the memory buses used to access NAND flash and DDR2 RAM. Memory

packages could come from multiple vendors.

Structure[edit]

Microcontroller-based system on a chip

A typical SoC consists of:

A microcontroller, microprocessor or DSP core(s). Some SoCs—called multiprocessor

system on chip (MPSoC)—include more than one processor core.

Memory blocks including a selection of ROM, RAM, EEPROM and flash memory.

Timing sources including oscillators and phase-locked loops.

Peripherals including counter-timers, real-time timers and power-on reset generators.

External interfaces including industry standards such

as USB, FireWire, Ethernet, USART, SPI.

Analog interfaces including ADCs and DACs.

Voltage regulators and power management circuits.

These blocks are connected by either a proprietary or industry-standard bus such as

the AMBA bus from ARM Holdings. DMAcontrollers route data directly between

external interfaces and memory, bypassing the processor core and thereby increasing the data

throughput of the SoC.

Design flow[edit]

System-on-a-chip design flow

A SoC consists of both the hardware described above, and the software controlling

the microcontroller, microprocessor or DSPcores, peripherals and interfaces. The design flow for

a SoC aims to develop this hardware and software in parallel.

Most SoCs are developed from pre-qualified hardware blocks for the hardware elements

described above, together with thesoftware drivers that control their operation. Of particular

importance are the protocol stacks that drive industry-standard interfaces like USB. The

hardware blocks are put together using CAD tools; the software modules are integrated using

asoftware-development environment.

Chips are verified for logical correctness before being sent to foundry. This process is

called functional verification and it accounts for a significant portion of the time and energy

expended in the chip design life cycle (although the often quoted figure of 70% is probably an

exaggeration).[2] With the growing complexity of chips, hardware verification

languages likeSystemVerilog, SystemC, e, and OpenVera are being used. Bugs found in the

verification stage are reported to the designer.

Traditionally, engineers have employed simulation acceleration, emulation and/or an FPGA

prototype to verify and debug both hardware and software for SoC designs prior to tapeout. With

high capacity and fast compilation time, acceleration and emulation are powerful technologies

that provide wide visibility into systems. Both technologies, however, operate slowly, on the

order of MHz, which may be significantly slower – up to 100× slower – than the SoC’s operating

frequency. Acceleration and emulation boxes are also very large and expensive at $1M+.

FPGA prototypes, in contrast, use FPGAs directly to enable engineers to validate and test at, or

close to, a system’s full operating frequency with real-world stimulus. Tools such as Certus [3] are

used to insert probes in the FPGA RTL that make signals available for observation. This is used

to debug hardware, firmware and software interactions across multiple FPGA with capabilities

similar to a logic analyzer.

After debug the hardware of the SoC follows the place-and-route phase of the design of an

integrated circuit or ASIC before it is fabricated.

Conclusion

A System-on module (SoM) offers a unique approach to product development and the often fully

custom electronics typically contained within sophisticated devices. A SoM helps system

designers realize a fully customized electronics assembly, complete with custom interfaces and

form factor without the effort of a ground-up electronics design. Customers can purchase an off-

the-shelf SoM and marry it to an easy to develop custom base board to create a solution

functionally identical to one that is fully custom-engineered.  This method reduces product

development costs while decreasing shortening time to market and technical risk. Critical Link

provides a range of SoM offerings in its MityDSP family. The MityDSP is a series of highly-

configurable, small form factor embedded CPU engines. These combine DSP and/or FPGA

and/or ARM processors that are optimized for custom data collection and processing, and meet

the needs of a broad range of scientific and industrial applications. More on SoM The system on

module, which is sometimes referred to as a computer-on module (CoM), is designed to plug

into a carrier, or base board, and is generally a small processor module with a CPU and standard

I/O capability. The complex effort associated with designing a CPU subsystem is avoided by

using SoM functionality and a custom base board. There are two SoM families. There are a

number of benefits to the SoM approach vs. ground-up development. These include cost savings,

reduced risk, a variety of CPU choices, decreased customer design requirements, a small

footprint, and, since software developers can use off the shelf hardware with the same processing

core as the finished product, the ability to perform hardware and software development in

parallel.