IT Engineer are high-level IT personnel who design, install, and maintain a company's computer systems. They are responsible for testing, configuring, and troubleshooting hardware, software, and networking systems to meet the needs of the employer.

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Lab Two
Motherboard
Objectives
 Understand functionality and Architecture of Motherboard
 Identify components onMotherboard
 Practice Connecting components on Motherboard
Safety
Use anti-static electric discharge pad or wear shoes before touching motherboard
Do not touch pins inside Processor Socket

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Motherboard
Motherboard is the Printed circuit board and it is the main component of the system,
every component internal or external connects directly or indirectly to motherboard.
It is also known as mainboard or printed circuit board, system board. It is made of
fiberglass brown or green typically with a meshwork of copper lines these lines are
electronic circuits through which power, data, and control signals travel. Group of
these lines assigned a set of functions, is collectively called a “bus”.
There are ways in which components are connected to the motherboard.
1. Integrated in to the circuit board of the motherboard (in build video, audio, NIC
controllers)
2. Attached through connectors, sockets, slots on board (processor, RAM, HDD,
CD/DVD)
3 Attached through external back panel or front panel (Keyboard, Mouse, Speakers,
USB drive)
Form Factors of Motherboard
The form factor refers to the physical dimensions (size and shape) as well as certain
connector, screw hole, and other positions that dictate into which type of case the
board will fit.

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Main Components of Motherboard
 Processor Socket
 Memory Slots
 Chipset
 Bus Architecture
 Firmware
 BIOS
 CMOS
 Motherboard Connectors
 Adapter cards Slots
Processor Socket
Processor is mounted on the motherboard in a socket.
Types of Socket
 Pin Grid Array (PGA)
 Land Grid Array (LGA) (socket T)
 Ball Grid Array (BGA)
 Flip Chip PGA
Figure 4: Processor Sockets

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Primary Memory Slots
 172-pin MicroDIMM, used for DDR SDRAM
 184-pin DIMM, used for DDR SDRAM
 200-pin SO-DIMM, used for DDR SDRAM and DDR2 SDRAM
 204-pin SO-DIMM, used for DDR3 SDRAM
 214-pin MicroDIMM, used for DDR2 SDRAM
 240-pin DIMM, used for DDR2 SDRAM, DDR3 SDRAM and FB-DIMM
DRAM
Figure 5: Memory Slot
Chipset
Chipset refers to a group of integrated circuits, or chips, that are designed to work together.
A chipset controls the system bus structures and facilitates the movement of data and
instructions between the Processor, cache memory and internal and external peripheral
devices.
Two main chips in chipset are Memory Control Hub (Northbridge) and Input Output Control
Hub (Southbridge). The Northbridge links the CPU to very high-speed devices, especially
main memory and graphics controllers, and the Southbridge connects to lower-speed
peripheral buses (such as PCI ). In many modern chipsets, the Southbridge actually contains
some on-chip integrated peripherals, such as Ethernet, USB, and audio devices.
Chipset controls the flow of bits that travel between the CPU, system memory, and the
motherboard bus. Efficient data transfers, fast expansion bus support, and advanced power
management and many more are the features of chipset.
A chipset is usually designed to work with a specific family of microprocessors. Because it
controls communications between the processor and external devices, the chipset plays a
crucial role in determining system performance.

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Every chipset has a specific model number and its two main chips North Bridge and South
Bridge model numbers. We can identify them in following ways
1. Using Chipset Identification Utility: download a tool from Intel or third party website
and install the tool to identify the chipset model.
2. Through Device manager: click Start » click Control Panel » double-click the
System icon » click the Hardware tab » click Device Manager Click the sign to
expand the System devices entry. Look for the chipset name in a string similar to the
following: "Intel® 955X Memory Controller Hub - 2774". In this example, the chipset
is an Intel® 955X Express Chipset.
3. Product Documentation
4. Chipset Marking: Open the System case and on the motherboard find the
chipset marking or chipset model number.
Figure 6: Chipset Model

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Figure 7: Chipset Block Diagram
Bus Architecture
It refers to pathways that power, data, and control signals use to travel from one
component to another in the computer. There are different types of buses.
Processor Bus: data and control signals to and from processor travel through this bus it
is also known as Front Side Bus
Memory Bus: data and control signals to and from primary memory (RAM) travel
through this bus.
Input Output Bus: data and control signals to and from input and output devices travel
through this bus.

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The system crystal determines the speed at which a CPU and the rest of the PC operate.
This is called the system bus speed. The system crystal is usually a quartz oscillator, very
similar to the one in a wristwatch, soldered to the motherboard (Figure 8). The quartz
oscillator sends out an electric pulse at a certain speed, many millions of times per second.
This signal goes first to a clock chip that adjusts the pulse, usually increasing the pulse sent
by the crystal by some large multiple. As long as the PC is turned on, the quartz oscillator,
through the clock chip, fires a charge on the CLK wire, in essence pushing the system along.
Before you install a CPU into a
System, you must make sure that the crystal and clock chip send out the correct clock pulse
for that particular CPU.
Figure 8: Quartz Oscillator
Firmware
Firmware refers to software instructions, usually stored on ROM chips. Firmware
exits on most PC components, such as video adapter, hard drives, network adapter
and printers. These instructions are always available, so they are not reprogrammed
every time the computer is started.
BIOS
BIOS is a term that stands for basic input/output system, which consists of low-level

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software that controls the system hardware and acts as an interface between the
operating system and the hardware. It is responsible for informing the processor of
the devices present and how to communicate with them. Whenever the processor
makes a request of a component, the BIOS steps in and translates the request into
instructions that the component can understand.
Older Computers contained a true Read-Only BIOS that cannot be altered. Now the
flash BIOS can be electronically upgrade so that it can recognize new device type.
Given below is the illustration of system as layers where BIOS is in between
hardware and Operating System.
Application Programs
Operating System
ROM BIOS and Device Drivers
HARDWARE
Figure 9: PC System Layers
CMOS
Complementary Metal Oxide Semiconductor is another type of firmware, which stores
settings such as date and time, keyboard settings, boot sequence. Interrupt Request line
and I/O resources that BIOS uses. It is also referred as RTC/NVRAM (Real Time Clock
Non Volatile RAM), this chip is volatile but it is supplied with power from Lithium
Battery as show in the given below figure 10.
You can enter and edit the settings by entering the computer’s Setup Program during boot up
process. This is also referred as BIOS Setup.
Note: BIOS and CMOS not to be confused they are two separate components.
Figure 10: CMOS Battery

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Mother Board Connectors
All of the components of a computer directly or indirectly connect to motherboard and some
are in-built. In many ways connection is established they are as follows.
 On Board Connection: here component is fixed on to board using Slots and Sockets
on mother board. Example Processor, RAM, Network card, AGP card etc
 Internal Connection: Components inside the System case connects to mother board
using connectors. Example Hard Disk Drive, CD/DVD Drive, etc
 External Connection: Components external to the system case are connected through
back-panel.
SLOTS: slot is an narrow opening through which an object can pass. Here on motherboard
a slot is used to fix a adapter card in to it. There are different types of slot available but most
common which are seen on most of the motherboards are given below.
PCI Slots (Peripheral Component Interconnect): PCI is bus to connect the expansion cards
like network card, modem card, video card etc. There are many variants of PCI bus as
follows
Figure 11 PCI Slot
PCI Slot is the most common slot found on almost all of the mother boards.
PCI Express (PCIe): this slot is as PCI but with numerous improvements such as maximum
system bus throughput, high speed, and low pin count.

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Figure 12: PCI E Slots
AGP Slot (Accelerated Graphics Port) is a high-speed point-to-point channel for
attaching a video card to a computer's motherboard, primarily to assist in the acceleration
of 3D computer graphics. It is more a high performance point-to-point connection used
only by video cards. But now AGP Cards are connected in to PCIe Slots.
On the chart below we compared the transfer rates of the PCI, AGP and PCI Express
busses.
The PCI Express bus is hot plug, i.e., it’s possible to install and remove PCI Express
boards even when the PC is on. PCI Express slot is connected to the motherboard
chipset using a dedicated lane, not sharing this lane (data path) with other PCI
Express slots.

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The PCI Express x16 slot was developed to be used by video cards. PCI Express has
replaced AGP as the default interface for graphics cards on new systems. With a few
exceptions, all graphics cards being released as of 2009 from ATI and NVIDIA use
PCI Express. NVIDIA uses the high bandwidth data transfer of PCIe for its Scalable
Link Interface (SLI) technology, which allows multiple graphics cards of the same
chipset and model number to be run in tandem, allowing increased performance.
Figure13: cards for different slots.
AMR, CNR, ACR Slots: AMR (Audio Modem Riser), CNR (Communications and
Network Riser) and ACR (Advanced Communications Riser) are slots that you can
find on your motherboard that have the same goal: to install HSP (Host Signal
Processing) devices to your PC. These devices can be modems, sound cards and
network cards.
Figure 14: AMR,CNR,ACR Slots.

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Memory Slots: Memory slots like SIMM and DIMM will be discussed in memory
chapter.
Sockets: Sockets will be disused in detail in Processor chapter.
Power Connectors: Power Supply (SMPS) supplies power to mother board.
Different Form factors of power supply are available for desktop computers, such as
ATX, BTX, LPX, microATX , Flex ITX.
ATX (Advanced Technology Extension) is widely used. The ATX specification
requires the power supply to produce three main outputs, +3.3 V, +5 V and +12 V.
Figure 15: Power Connectors.

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Parallel ATA Connector (PATA): It is 40 Pin connector. A ribbon cable connects
the Hard disk drive and CD/DVD Drive to the interface, as shown in the figure
below.
Figure 16: PATA Connectors.
Serial ATA (SATA): SATA is the High Speed Interface with seven conductors,
SATA ribbon cable can be of 1 meter, it enables Hot-plugging. Figure below show cable
and connector on motherboard.
Figure 17: SATA Connector

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Back Panel Connectors
ATX boards have a unique double-high connector area for all the built-in connectors on the
motherboard. When the computer is mounted, those motherboard parts show up at the
computer case back panel. They are used to plug the mouse, keyboard, monitor, printer,
sound and any other peripherals you may have.

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Install the mother board
1. There are a lot of screw holes on the system case. Because it corresponds to various
mother boards.
2. The mother board is fixed to the system case with a screw and a spacer.