Like the PCI single board computer (SBC), the ISA single board computer is also referred to as a half size SBC. The difference is that the ISA SBC has ISA contacts whereas the PCI SBC has PCI contacts. Also when the ISA SBC is connected to the ISA backplane it creates an 8 or 16 bit bus. The PCI creates a 32 bit bus. The ISA single board computer is a processor board which requires an ISA backplane to connect to. It has some basic functionality including video, USB, COM, and LAN ports. These boards are mainly used within industrial PCs due to the fact that they require a backplane. Since ISA is an older technology than the PCI it typically uses older processors such as the VIA Eden, VIA C3, AMD Geode GX1, as well as 386 and 486 processors.
Since the ISA board is typically used within an industrial computer, it is best suited for applications such as industrial automation, factory automation, telecommunication, instrumentation, CNC Machines, Man Machine Interface, CTI (Computer Telephony Integration), and DVR (Digital Video Recorder)
A PCI single board computer, also known as a half size single board computer, is a computer processor board which has some basic functionality. This functionality includes video, USB, COM, and LAN ports. It is mainly used within an industrial PC because the PCI single board computer requires a PCI backplane which it must connect to. As opposed to the ISA single board computer, the PCI single board computer creates a 32 bit bus with the PCI backplane. The processors mostly supported on the PCI single board computer are the Pentium M, Celeron M, Pentium 3, Celeron, VIA Eden, and the VIA C3.
Like other industrial computer boards, the PCI single board computer is best suited for applications involving industrial automation, factory automation, telecommunication, instrumentation, CNC Machines, Man Machine Interface, CTI (Computer Telephony Integration), and DVR (Digital Video Recorder).
ASingle Board Computer is a complete computer built on a single circuit board that contains a complete computer, including microprocessor, memory, Ethernet, I/O, Video and Audio output. The design is always centered around a microprocessor. The first true single-board computer was probably the MYCRO-1, built around the Intel 8080 CPU.Single Board Computer is of a specific form factor similar to other plug-in cards and is intended to be used in a backplane. Some architectures are dependant entirely on single-board computers, such as PICMG, ISA, PCI, Compact PCI, VME architecture, etc. In the 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, except that the backplane determines the slot configuration. Backplanes are available with a mix of slots (ISA, PCI, PCIX, PICMG etc), usually totaling 20 or less, meaning it will fit in a 19" rackmount enclosure, or some wallmount compact chassis.
PC104 (or PC/104) is an embedded computer standard by the PC104 Consortium, that defines both a form factor and computer bus. Unlike the popular ATX form factor and PCI computer bus currently used for most PC’s, PC104 is intended for specialized uses, such as for a data acquisition or industrial control system. This form factor does not have a backplane, instead components come in modules that are stacked one atop another. The standard size is 3.55 × 3.75 inches (90.17 mm × 95.89 mm), and the height depends on the height of the individual modules and the number of modules connected. A typical installation includes a motherboard, analog-to-digital converter, and digital I/O module.
The 1992 PC104 computer bus utilizes 104 pins. These pins include all the normal lines used in the ISA bus, with additional ground pins added to ensure bus integrity. Signal timing and voltage levels are identical to the ISA bus, with lower amperage requirements.
The PC/104 plus single board computer specification was introduced by the PC104 Embedded Consortium. As technology progressed there was a need for higher performance bus throughput on embedded computers, especially for graphics devices and other high speed I/O devices. For example, the PC/104 plus video capture card for digital video recording applications. The PC/104 plus met this challenge by adding a PCI bus on the PC104 form factor. Surprisingly, the PC/104 plus was able to maintain the same physical size, mounting and electrical interconnects as the PC104.
Since the PC/104 plus includes both the ISA and PCI bus architectures, it is able to support the x86 (386, 486, 586, AMD Geode, VIA C3, Eden, Pentium III, Celeron III, Pentium 4, Pentium-M and Celeron-M) processors.
The PCI-104 specification was introduced by the PC104 Embedded Consortium. PCI-104 is identical to the widely used PC104 plus combined ISA and PCI embedded standard except that the PC104 AT and XT connectors for the ISA bus are removed. Eliminating the large ISA bus connector gives an additional 10% of board area for either larger CPU chipsets, higher levels of integration, and/or I/O connectors. The PCI-104 specification still maintains the small 3.550 x 3.775-inch size, rugged design, and self-stacking architecture for embedded applications set by the PC104 Plus standards. It can also be offered in a fan less solution.
While the current PC104 and PC104 Plus standards will retain the ISA bus and support the large existing base of PC104 add-on modules, the PCI-104 specification defines a standard with PCI-compatible I/O features which allows video, audio, Ethernet, and contemporary communications to be handled on the single board computer.
Another benefit of the new PCI-only format is its processor independence. ISA is primarily used as an x86 expansion bus in PC compatible systems, whereas, PCI can not only use the 386, 486, PIII, 586, AMD Geode, VIA C3, Eden, Celeron III, P4, Pentium M, and Celeron M, but it can also support other processor architectures as well.
An Industrial computer can be adopted by many different industries for a wide range of applications. The physical components typically include a slot CPU card, a multi-slot backplane and some add-on cards all enclosed in an industrial chassis. There are several differences between an industrial PC (IPC) and a consumer PC. For starters, an Industrial PC is extensively tested. It must pass the 24 hour burn-in test and the vibration ESS test. It must also meet the IPC 610 class II or class III soldering standard. These testing procedures and standards separate the Industrial PC from the consumer PC. The following table lists some of the design and manufacturing differences:
The Industrial PC comes in half-size and full-size form factors. The half-size form factor has either a PCI or ISA bus. The full-size board, referred to as the PICMG, includes both the PCI and ISA busses. The different form factors refer to the architectural layout of the single board computer. For example, the PCI informs us that the board is 185mm x 122mm, it has a 32 bit bus and requires a PCI backplane. The industry standard (ISA) board is the same size, however, it has an 8 or 16 bit bus and requires an ISA backplane. Lastly, the PICMG is an all-in-one computer that includes both PCI and ISA slots and is 339.5mm x 121.5mm.
Some of the applications best suited for an industrial computer are factory automation, industrial automation, telecommunications, CNC machines, Man-Machine Interface (MMI), Computer Telephony Integration (CTI), and Digital Video Recording (DVR).
Embedded computers are offered in many different form factors, including EPIC, Embedded ATX, Mini-ITX, 5.25”, EBX, 3.5”, PC/104, PC/104 plus, PCI 104, and even the LPX. But what is an embedded computer? An embedded computer is a device which has its own computing power dedicated to specific functions, usually a microprocessor and firmware. The computer becomes an integral part of the device as opposed to a stand alone computer. Embedded computers are similar to an industrial computer in that they both are all-in-one computers. The key difference is that an embedded PC does not require a backplane, allowing all peripheral functionality to be accomplished through the serial, parallel, USB, VGA/LCD, IDE, audio, solid state disks (SSD), and even PC/104 expansion connectors. An embedded computer can be provided in a low power fanless solution, it can also have the CPU embedded on board. These boards require that software integrate the peripheral functionality and operating system. The most common operating systems found on an embedded computer are WinCE, Windows XPe, Embedded Linux and many others. Ultimately, an embedded computer board is an all-in-one computer that is compact.
Like industrial computers, embedded computers are made to run 24/7 and withstand harsh environments including areas of intense vibration, high temperature, high humidity and dust.
A panel PC has the functionality of a computer and yet is limited to about the size of a monitor sometimes even smaller. A panel PC is capable of providing peripheral functionality through audio, video, USB, LAN, PS/2, compact flash, serial ports, parallel ports and even PCI bus expansion slots. They can be provided with PCI backplanes, or ISA backplanes they can even be all in one single board computers. They are also easily mounted or hung on the wall which allows a panel PC to be utilized virtually anywhere. Panel PCs are provided with TFT LCD in sizes 7”, 10.4”, 12.1” and 15” with touch screen capabilities.
These low cost compact systems can be used for applications such as industrial automation, human machine interface (HMI), KIOSK, Vehicle PC, CNC Controller and many other industries.
EPIC stands for embedded platform for industrial computing. The size of the EPIC form factor is larger than the PC104 yet smaller than the EBX form factor, in fact it is 115 x 165mm. As technology progresses, engineers strive to add more functionality and performance to single board computers requiring the least amount of space, the EPIC form factor helps to accomplish this goal. It provides embedded systems manufacturers who require faster CPUs and or more I/O than on PC104 a broadly supported platform to work with. Another key goal was to develop a board that could provide a bridge from current technology into the future, in other words it would be able to support PCI express, ExpressCard and other technologies as they become available. In order to support a wide variety of I/O, EPIC also supports the PC104 and PC104 plus expansions. The CPUs most widely supported on the EPIC form factor range from the ultra low voltage (ULV) Celeron M to the Pentium M processors. The EPIC form factor can also be offered in a fanless solution.
EPIC is most commonly utilized by applications such as data acquisition, video processing, telecommunications, networking, motion control plus, field wiring termination, even I/O circuit protection and many others.
Embedded ATX form factor, also referred to as emb ATX, was designed to satisfy the needs of applications which require a motherboard with a constrained height. Similar to the microATX, the embedded ATX form factor has a fairly large (244mm x 244mm) dimension. It was designed with two goals in mind. The first goal was to develop a form factor for low profile applications. Secondly create the lowest cost solution possible. The main benefits of the embedded ATX single board computer is that is accommodates current processor technologies combined with an ATX family backwards compatible rear I/O panel as well as a low profile PCI expansion via a riser card. The riser card allows the PCI card to sit parallel with the embedded ATX board. The most common operating systems (OS) that are supported include the Windows family (98, ME, NT, 2000, XP, XPe, even CE.Net), several Linux OS, SCO Unix and QNX.
Since the embedded ATX is fairly large it can provide lots of functionality for example, it is great for multimedia applications that are graphics intensive. The Embedded ATX is also best suited for applications such as industrial automation, factory automation, medical systems, and point of sales (POS).
While the Mini-ITX single board computer shares much in common with the Micro-ATX and Flex-ATX, there have also been a few advances. Physically, the mini ITX at 170mm x 170mm is about 33% smaller than the flex ATX and is described as the “worlds smallest x86 mainboard platform.” One of the key advantages of the Mini-ITX single board computer is that it is based on the low power VIA processor platform, which include the VIA C3, and Eden processors. The mini ITX can also provide the benefits of a fanless solution. It is also backwards compatible with both the flex ATX and the micro ATX. The mini-ITX is considered to be a single board computer because you can have all the functions of an embedded computer system by just adding some memory, a hard drive and a power supply.
The Mini ITX single board computer can be best utilized by applications such as industrial automation, factory automation, medical system, instrumentation, Point Of Sales (POS), KIOSK, and even Gaming.
The embedded systems market consistently demands improvements in performance and functionality, while seeking size and cost reductions at the same time. The EBX, embedded board expandable, standard creates an opportunity for embedded systems manufacturers to create solutions which fit the requirements of embedded system OEMs. It also provides convenience, risk reduction, scalability and flexibility of off the shelf products. This is an advantage to embedded system OEMs because it reduces their time to market while also reducing their cost. EBX combines the standard footprint of the 5.25” form factor with open interfaces. It is small enough to be utilized in embedded systems, yet large enough to provide the full functionality of an embedded computer system. It can support several different processors including, 386, 486, 586, Pentium M, Celeron M, Pentium 4, Celeron, Pentium III, VIA Eden, C3, and AMD Geode. As opposed to the standard, the EBX single board computer provides an expansion which allows easy modular additions. This expansion is based on widely used industry standards such as IEEE P996, PC104, PCI, PC/104 plus and PMCIA. The PC104 places the ISA bus on compact 3.6” x 3.8” modules with self-stacking capability. The PC/104 plus adds the PCI bus to the PC/104. The EBX single board computer integrates all of these standards into one highly embedded single board computer.
The 5.25” EBX single board computer can be best utilized for applications such as industrial automation, factory automation, medical system, instrumentation, point of sales (POS), KIOSK, and even gaming.
A backplane is a circuit board that connects physical interfaces (connectors) in parallel with one another, forming a computing bus for a slot CPU card within an industrial PC system. A backplane is available with PCI connectors, ISA connector or both, for PICMG. A backplane is also available with 3, 4, 5, 6, 7, 14, and 20 slots. The different slot types allow a flexible range of printed circuit boards (PCB) to be connected to the backplane, including various add-on cards, slot CPU cards and even single board computers, ultimately making up a complete computer system. This flexibility enables backplanes to be best suited for industrial PCs.
Also, due to their superior reliability, backplanes are the preferred medium over cabling systems. The cables in a cabling system need to be flexed every time a card is added, and “flexing” causes mechanical failures. Backplanes do not encounter this problem so the lifetime of a backplane is limited only by its connectors.
Backplanes are offered in passive and active forms. Passive backplanes offer no active bus driving circuitry whereas active backplanes include chips which buffer various signals to the slots. Generally, backplanes are differentiated from motherboards because of the lack of on-board processing power where the CPU is on a plug-in card.
A watchdog timer (WDT) is a computer hardware timing device that performs a specific operation after a certain period of time if something goes wrong with an electronic system and the system does not recover on its own. For example, to trigger a system reset if the main program hangs, or neglects to regularly service the watchdog. So the intention of WDT is to bring the system back from the hung state into normal operation.
A WDT contains a digital counter that counts down to zero at a constant speed from a preset number. If the counter reaches zero before the computer recovers, a signal is sent to designated circuits to perform the desired action