Motherboard C A O

Motherboard

2006-2007 REPORT SUBMITTED TO THE FACULTY OF ELECTRONICS AND COMMUNICATION ENGINEERING NATIONAL INSTITUTE OF TECHNOLOGY, WARANGAL (A.P) (DEEMED UNIVERSITY) BACHELOR OF TECHNOLOGY IN ELECTRONICS AND COMMUNICATION ENGINEERING SUBMITTED BY DEVENDER SINGH BUDHWAR (04411)

Under the Guidance of Mr. K.V. Sridhar DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING NATIONAL INSTITUTE OF TECHNOLOGY (DEEMED UNIVERSITY) WARANGAL-506004(A.P)

Acknowledgements

I would like to express our sincere thanks to our faculty, K.V.

Sridhar,

Department

Communication

Engineering,

of

Electronics

National

and

Institute

of

Technology, Warangal for his constant encouragement, splendid and gracious guidance throughout our work. He has been a constant source of inspiration and helped us in each stage. We express our deep gratitude to him for such encouragement and kindly cooperation.

Devender Singh Budhwar (4411) ¾ B.Tech. (E.C.E.)

CONTENTS 1. Introduction to motherboards 2. Basics 3. Temperature and Reliability 4. Physical Form Factor 5. Connections • Peripheral card slots(PCS) • Accelerated Graphics Port(AGP) • Basic input/output system (BIOS) • Integrated drive electronics (IDE) • Universal Serial Bus (USB) • Bus 6. Common Manufacturers 7. References

INTRODUCTION

Motherboard : A motherboard is also known as a main board, system board and logic board. A common abbreviation is ‘mobo'. They can be found in a variety of electrical devices, ranging from a TV to a computer. Generally, they will be referred to as a motherboard or a main board when associated with a complex device such as a computer, which is what we shall look at. Put simply, it is the central circuit board of your computer. All other components and peripherals plug into it, and the job of the motherboard is to relay information between them all. Despite the fact that a better motherboard will not add to the speed of your PC, it is none-the-less important to have one that is both stable and reliable, as its role is vital. A motherboard houses the BIOS (Basic Input/Output System), which is the simple software run by a computer when initially turned on. Other components attach directly to it, such as the memory, CPU (Central Processing Unit), graphics card, sound card, hard-drive, disk drives, along with various external ports and peripherals. The motherboard is usually thought of as the most important part of a computer. Despite this a lot of people don't know a lot about it except it's the big board everything plugs into. There's a lot more to it than this so we've decided to devote a whole article just to it!

BASICS

Connects to : • • • o o o

Devices via Cables Chips via Sockets Riser Cards via one of PCI AGP PCI Express

Difference between motherboards : A more in-depth look at this vital component There are a lot of motherboards on the market to choose from. The big question is, how do you go about choosing which one is right for you? Different motherboards support different components, and so it is vital you make a number of decisions concerning general system specifications before you can pick the right motherboard. If you purchase your case before the rest of the components, the first factor to think about concerning motherboards is the size, or form factor. A ‘form factor’ is a standardized motherboard size. If you think about fitting a motherboard in a case, there are a number of mounting holes, slot locations and PSU connectors. The most popular motherboard form factor today is ATX, which evolved from it's predecessor, the Baby AT, a smaller version of the AT (Advanced Technology) form factor. Generally speaking, nowadays a standard computer will have an ATX form factor motherboard: only special cases require different form factors. In both the AT and ATX designs, the computer components included in the motherboard are: • • • • • •

The microprocessor (Optionally) coprocessors Memory basic input/output system (BIOS) Expansion slot Interconnecting circuitry

Additional components can be added to a motherboard through its expansion slot. The electronic interface between the motherboard and the smaller boards or cards in the expansion slots is called the bus factors needed to consider : The first important differential is which CPU the board supports. Two of the biggest makes of CPUs at the moment are Intel and AMD, yet you cannot buy motherboards that support the use of either: it will support one or the

other, due to physical differences in the connectors. This is often referred to as a type of ‘platform’.for example, an ‘Intel platform motherboard' means a motherboard with an Intel CPU. Furthermore, you must choose a specific type of processor; for example, an AMD Athlon 64 or Pentium 4. Therefore, you must choose which CPU you want before you can choose your motherboard. Both Intel and AMD processors are capable of running the same applications, but there are differences in price and performance depending on which one you choose. A typical motherboard provides attachment points for one or more of the following: CPU, graphics card, sound card, hard disk controller, memory (RAM), and external peripheral devices. The connectors for external peripherals are nearly always color coded according to the PC 99 specification. All of the basic circuitry and components required for a computer to function sit either directly on the motherboard or in an expansion slot of the motherboard or are connected with a cable. The most important component on a motherboard is the chipset. It often consists of two components or chips known as the Northbridge and Southbridge, though they may also be integrated into a single component. These chips determine, to an extent, the features and capabilities of the motherboard. . It contains the chipset, which controls the operation of the CPU, the PCI,ISA, AGP, and PCI Express expansion slots, and (usually) the IDE/ATA controller as well. Most of the devices that can be attached to a motherboard are attached via one or more slots or sockets, although some modern motherboards support wireless devices using the IrDA, Bluetooth, or 802.11 (Wi-Fi) protocols. There are different slots and sockets for CPUs, and it is necessary for a motherboard to have the appropriate slot or socket for the CPU. Newer sockets, those with a three digit number, are named after the number of pins they contain. Older ones are simply named in the order of their invention, usually with a single digit.

TEMPERATURE AND RELIABILITY

Generally, motherboards are air cooled with heat sinks on the larger chips such as the northbridge and CPU, and they have monitored sockets for case fans. Newer motherboards have integrated temperature sensors to detect motherboard and CPU temperatures, which can be used by the BIOS or Operating system to regulate fan speed. The removal of waste thermal energy became a major concern for workstation PCs around 2000, with the problem becoming more severe over time as computer systems continued to consume more and more power. A study of the German c't computer magazine (c't 2003, vol. 21 pg. 216221) found that some spurious computer crashes and general reliability issues ranging from screen image distortions to I/O read/write errors can surprisingly be attributed not to software or peripheral hardware but to aging PC motherboards. Motherboard voltage regulation uses electrolytic capacitors. These capacitors exhibit aging effects which depend on the temperature of the parts, since their water based electrolytes slowly evaporate leading to capacity loss and motherboard malfunctions due to voltage instabilities. While most capacitors are rated for 2000 hours at 105 degrees Celsius (life formula [1]), their expected design life roughly doubles for every 10 degrees Celsius below this. At 45 degrees Celsius a lifetime of 15 years can be expected, which appears reasonable for a computer mainboard. In the past, many manufacturers delivered substandard capacitors, which would reduce this life expectancy figure. With inadequate case cooling this can become a serious problem. It is, however, possible to find and replace broken capacitors on PC main boards. For more information on certain types of premature capacitor failure on PC motherboards, see capacitor plague.

PHSICAL FORM FACTOR

The motherboard fits into the computer case with screws or clips. There are many form factors, or sizes of motherboard. In general, it is necessary for the case, power supply, and motherboard to conform to the same standard in order for them to operate properly.

On most PCs, it is possible to add memory chips directly to the motherboard. You may also be able to upgrade to a faster PC by replacing the CPU chip. To add additional core features, you may need to replace the motherboard entirely.

Motherboard is sometimes abbreviated as mobo. Motherboards are available in a variety of form factors, which usually correspond to a variety of case sizes. Summary of some PC motherboard sizes available : • AT form factor (Advanced Technology) - the first form factor to gain wide acceptance, successor to PC/XT. Also known as Full AT, it was popular during the 386 era. Now obsolete, it is superseded by ATX. •

• • • •

• •

Baby AT - IBM's successor to the AT motherboard, it was functionally equivalent to the AT but gained popularity due to its significantly smaller physical size. It usually comes without AGP port. ATX- the evolution of the Baby AT form factor, it is now the most popular form factor available today. ETX , used in embedded systems and single board computers. Mini-ATX - essentially the same as the ATX layout, but again, with a smaller footprint. MicroATX - again, a miniaturization of the ATX layout. It is commonly used in the larger cube-style cases such as the Antec ARIA. FlexATX - a subset of microATX allowing more flexible motherboard design, component positioning and shape. LPX - based on a design by Western Digital, it allows for smaller cases based on the ATX motherboard by arranging the expansion cards in a riser (an expansion card in itself, attaching to the side of the motherboard - image). This design allows the cards to rest parallel to the motherboard as opposed to perpendicular to it. The LPX motherboard is generally only used by large OEM manufacturers.

While most desktop computers use one of these motherboard form factors, laptop (notebook) computers generally use highly integrated, customized and miniaturized motherboards designed by the manufacturers. This is one of the reasons that notebook computers are difficult to upgrade and expensive to repair - often the failure of one integrated component requires the replacement of the entire motherboard, which is also more expensive than a regular motherboard due to the large number of integrated components in it.

CONNECTIONS AGP(Accelerated Graphics Port) it all started in 1973, when Xerox completed the Alto, the first computer to use a graphical user interface. This innovation forever changed the way the people work with their computers. Today, every aspect of computing, from creating animation to simple tasks such as word processing and e-mail, uses lots of graphics to create a more intuitive work environment for the user. The hardware to support these graphics is called a graphics card. The way this card connects to your computer is key in your computer's ability to render graphics. In this article, you will learn about AGP, or Accelerated Graphics Port. AGP enables your computer to have a dedicated way to communicate with the graphics card, enhancing both the look and speed of your computer's graphics. BIOS One of the most common uses of Flash memory is for the basic input/output system of your computer, commonly known as the BIOS (pronounced "bye-ose"). On virtually every computer available, the BIOS makes sure all the other chips, hard drives, ports and CPU function together. Every desktop and laptop computer in common use today contains a microprocessor as its central processing unit. The microprocessor is the hardware component. To get its work done, the microprocessor executes a set of instructions known as software . You are probably very familiar with two different types of software: •

The operating system - The operating system provides a set of services for the applications running on your computer, and it also provides the fundamental user interface for your computer. Windows 98 and Linux are examples of operating systems. (See How Operating Systems Work for lots of details.)

The applications - Applications are pieces of software that are programmed to perform specific tasks. On your computer right now you probably have a browser application.

IDE Controllers No matter what you do with your computer, storage is an important part of your system. In fact, most personal computers have one or more of the following storage devices: • • •

Floppy drive Hard drive CD-ROM drive

Usually, these devices connect to the computer through an Integrated Drive Electronics (IDE) interface. Essentially, an IDE interface is a standard way for a storage device to connect to a computer. IDE is actually not the true technical name for the interface standard. The original name, AT Attachment (ATA), signified that the interface was initially developed for the IBM AT computer. In this article, you will learn about the evolution of IDE/ATA, what the pinouts are and exactly what "slave" and "master" mean in IDE. USB(Universal Serial Bus) connectors Just about any computer that you buy today comes with one or more Universal Serial Bus connectors on the back. These USB connectors let you attach everything from mice to printers to your computer quickly and easily. The operating system supports USB as well, so the installation of the device drivers is quick and easy, too. Compared to other ways of connecting devices to your computer (including parallel ports, serial ports and special cards that you install inside the computer's case), USB devices are incredibly simple! In this article, we will look at USB ports from both a user and a technical standpoint. You will learn why the USB system is so flexible and how it is able to support so many devices so easily -- it's truly an amazing system! Anyone who has been around computers for more than two or three years knows the problem that the Universal Serial Bus is trying to solve -- in the past, connecting devices to computers has been a real headache!

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•

•

Printers connected to parallel printer ports, and most computers only came with one. Things like Zip drives, which need a high-speed connection into the computer, would use the parallel port as well, often with limited success and not much speed. Modems used the serial port, but so did some printers and a variety of odd things like Palm Pilots and digital cameras. Most computers have at most two serial ports, and they are very slow in most cases. Devices that needed faster connections came with their own cards, which had to fit in a card slot inside the computer's case. Unfortunately, the number of card slots is limited and you needed a Ph.D. to install the software for some of the cards.

The goal of USB is to end all of these headaches. The Universal Serial Bus gives you a single, standardized, easy-to-use way to connect up to 127 devices to a computer. A sample list of USB devices that you can buy today includes: • • • • • • • • • • • • • •

Printers Scanners Mice Joysticks Flight yokes Digital cameras Webcams Scientific data acquisition devices Modems Speakers Telephones Video phones Storage devices such as Zip drives Network connections

Connecting a USB device to a computer is simple -- you find the USB connector on the back of your machine and plug the USB connector into it.

The rectangular socket is a typical USB socket on the back of a PC. A typical USB connector, called an "A" connection

If it is a new device, the operating system auto-detects it and asks for the driver disk. If the device has already been installed, the computer activates it and starts talking to it. USB devices can be connected and disconnected at any time. Many USB devices come with their own built-in cable, and the cable has an "A" connection on it. If not, then the device has a socket on it that accepts a USB "B" connector.

A typical "B" connection The USB standard uses "A" and "B" connectors to avoid confusion: • •

"A" connectors head "upstream" toward the computer. "B" connectors head "downstream" and connect to individual devices.

By using different connectors on the upstream and downstream end, it is impossible to ever get confused -- if you connect any USB cable's "B" connector into a device, you know that it will work. Similarly, you can plug any "A" connector into any "A" socket and know that it will work.

PCI (Peripheral Component Interconnect) The power and speed of computer components has increased at a steady rate since desktop computers were first developed decades ago. Software makers create new applications capable of utilizing the latest advances in processor speed and hard drive capacity, while hardware makers rush to improve components and design new technologies to keep up with the demands of high-end software. There's one element, however, that often escapes notice - the bus. Essentially, a bus is a channel or path between the components in a computer. Having a high-speed bus is as important as having a good transmission in a car. If you have a 700-horsepower engine combined with a cheap transmission, you can't get all that power to the road. There are many different types of buses. In this article, you will learn about some of those buses. We will concentrate on the bus known as the Peripheral Component Interconnect (PCI). We'll talk about what PCI is, how it operates and how it is used, and we'll look into the future of bus technology. Bus The idea of a bus is simple -- it lets you connect components to the computer's processor. Some of the components that you might want to connect include hard disks, memory, sound systems, video systems and so on. For example, to see what your computer is doing, you normally use a CRT or LCD screen. You need special hardware to drive the screen, so the screen is driven by a graphics card. A graphics card is a small printed circuit board designed to plug into the bus. The graphics card talks to the processor using the computer's bus as a communication path. The advantage of a bus is that it makes parts more interchangeable. If you want to get a better graphics card, you simply unplug the old card from the bus and plug in a new one. If you want two monitors on your computer, you plug two graphics cards into the bus. And so on. Twenty or 30 years ago, the processors were so slow that the processor and the bus were synchronized -- the bus ran at the same speed as the processor, and there was one bus in the machine. Today, the processors run so fast that

most computers have two or more buses. Each bus specializes in a certain type of traffic. A typical desktop PC today has two main buses: •

•

The first one, known as the system bus or local bus, connects the microprocessor (central processing unit) and the system memory. This is the fastest bus in the system. The second one is a slower bus for communicating with things like hard disks and sound cards. One very common bus of this type is known as the PCI bus. These slower buses connect to the system bus through a bridge, which is a part of the computer's chipset and acts as a traffic cop, integrating the data from the other buses to the system bus.

Technically there are other buses as well. For example, the Universal Serial Bus (USB) is a way of connecting things like cameras, scanners and printers to your computer. It uses a thin wire to connect to the devices, and many devices can share that wire simultaneously. Firewire is another bus, used today mostly for video cameras and external hard drives.

The illustration above shows how the various buses connect to

Quick History : The original PC bus in the original IBM PC (circa 1982) was 16 bits wide and operated at 4.77 MHz. It officially became known as the ISA bus. This bus design is capable of passing along data at a rate of up to 9 MBps (megabytes per second) or so, fast enough even for many of today's applications. Several years ago, the ISA bus was still used on many computers. That bus accepted computer cards developed for the original IBM PC in the early

1980s. The ISA bus remained in use even after more advanced technologies were available to replace it. There were a couple of key reasons for its longevity: • •

Long-term compatibility with a large number of hardware manufacturers. Before the rise of multimedia, few hardware peripherals fully utilized the speed of the newer bus.

As technology advanced and the ISA bus failed to keep up, other buses were developed. Key among these were Extended Industry Standard Architecture (EISA) -- which was 32 bits at 8 MHz-- and Vesa Local Bus (VL-Bus). The cool thing about VL-Bus (named after VESA, the Video Electronics Standards Association, which created the standard) is that it was 32 bits wide and operated at the speed of the local bus, which was normally the speed of the processor itself. The VL-Bus essentially tied directly into the CPU. This worked okay for a single device, or maybe even two. But connecting more than two devices to the VL-Bus introduced the possibility of interference with the performance of the CPU. Because of this, the VL-Bus was typically used only for connecting a graphics card, a component that really benefits from high-speed access to the CPU. The backside bus is a separate connection between the processor and the Level 2 cache. This bus operates at a faster speed than the frontside bus, , so all that caching works as efficiently as possible.. In the 1990s, the backside bus was a wire that connected the main processor to an off-chip cache Bus Type

Bus Width

Bus Speed

MB/sec

ISA

16 bits

8 MHz

16 MBps

EISA

32 bits

8 MHz

32 MBps

VL-bus

32 bits

25 MHz

100 MBps

VL-bus

32 bits

33 MHz

132 MBps

PCI

32 bits

33 MHz

132 MBps

PCI

64 bits

33 MHz

264 MBps

PCI

64 bits

66 MHz

512 MBps

PCI

64 bits

133 MHz

1 GBps

COMMON MANUFACTURERS •

Intel Abit MSI ASUS Gigabyte Others

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Selecting Your Motherboard Among the Many Makes and Models : Choosing a motherboard can be an overwhelming task. After all, the industry boasts an incredible variety of motherboard makers and models, and each motherboard is compatible with either a specific Intel or AMD processor. Since the motherboard is the nerve center of your PC, the choice you make has a big impact on the kind of system you’ll create. Whether you have your mind set on an extreme gaming PC, a basic system the whole family can use, or a high-powered business computer, you should choose a motherboard that enhances the performance of your computer.

REFERENCES Tools • •

Downloads Mobo ID Tools

Websites • •

NVIDIA nForce Motherboards Find and select motherboards for Intel Processors

Tutorials • • •

Motherboard Components PC Technology Guide: Motherboards What is a motherboard?