DIT0102 Computer Motherboard

A computer motherboard is a board upon which entire computer is interconnected

A Motherboard has major parts such as1. Processor ( and its cooling system)2. Sockets3. Slots4. North bridge5. South bridge6. Primary memory7. Secondary memory8. CMOS battery9. Peripheral ports

Typical motherboard diagram is shown below

Typical Desktop motherboard.

Typically mounted Laptop Motherboard.

Motherboard architectural drawing

I. PROCESSOR • This is like the brain of computer, it receives input instructions and processes it to

produce the required output.• There are many vendors which manufacture Processors such as Intel, AMD, Motorola,

IBM, Cyrix (VIA) Alpha etc. • The most dominant processor maker is Intel followed closely by AMD• Each processor works with particular motherboard with unique processor socket/slot,

that is an Intel motherboard will not work with an AMD motherboard. • The processors will interface with its outside components via FSB, known as Front Side

Bus. Observe above diagram II. SOCKETS

• Computer motherboard has the first and its largest socket for its processors. There has been many types of computer sockets such as the old socket 7 which was the first and the last to work for three types of processors. Intel, AMD and Cyrix Processors. There after each processors from a different maker has a unique socket for their processors.

• Usually there are sockets, slots and embedded technologies for mounting a processor into a motherboard. Slots are not commonly used whereas the embedded processors are sandwiched into a motherboard just as any other components. Thus it is permanently soldered into a motherboard. If processor fails the entire motherboard will be thrown away. Normally embedded processors are for industrial applications and some PCs such as Cyrix (VIA) makes a all in one motherboards with embedded VIA processor.

• Typically there are two most commonly used processor sockets PGA (Pin Grid Array) and LGA (Land Grid Array)

• For PGA socket has HOLES while Processor has PINS, for LGA socket has PINS and processor has grid array CONTACTS. For Slot processor mounting system slot has CONTACTS and Processor Mounting board has Dual In Line CONTACTS.

LGA Socket with PINS

LGA grid array contacts

PGA socket with HOLES

Typical PGA Processors with PINS

Embedded Processor with heat sink mounted.

Processor cooling system involves• Thermal compound, it is a white compound applied between processor and heat sink• Heat sink with cooling fins• Fan

• Typical heat sinks with a fan

• IDE or PATA Socket, the socket mounts the PATA HDD into the motherboard via a flat cable. The pin number 1 in the flat cable is denoted by red colour and a guider such that the drive connection may interchanged. The socket colour denotes between primary and secondary drives and one socket and one cable may connect up to two drive in Master – Slave connections by jumper settings on the rear of drive, or cable select.

IDE, PATA motherboard socket

IDE, PATA one end connector. Both ends are alike (Similar)

• SATA Sockets, for this type of socket the cable is thinner and contains fewer cables (7) than that of PATA (40). The socket is also smaller than that of PATA and can connect a single drive.

Section of motherboard showing SATA sockets in yellow colour

SATA Data cable• CMOS battery socket

As illustrated in the practical training• BIOS chip socket

As illustrated in the practical training• Front Panel socket

As illustrated in the practical training• Front USB socket

As illustrated in the practical training• Front audio jack socket

As illustrated in the practical training

III. SLOTS• PCI Slots, holds system upgrade PCI Riser cards

Typical Section of motherboard, PCI slots

• RAM Slot, holds system memory few examples are shown bellow

Typical section of computer motherboard, DDR3 RAM slots, there are few more types of RAM slots

• AGP Slots, Holds VDU Riser card

Typical Computer motherboard section showing AGP marked with Yellow colour.

Typical AGP graphics card

• AMR Slot, Holds system Modem Riser card

Typical section of computer motherboard, AMR slot

IV. NORTH BRIDGE CHIPSET• As shown in the motherboard diagram and motherboard architecture diagramV. SOUTH BRIDGE CHIPSET• As shown in the motherboard diagram and motherboard architecture diagram

VI. PRIMARY MEMORY• As demonstrated in the lectureVII.SECONDARY MEMORY

As demonstrated in the lecture

VIII. PERIPHERAL PORTSAs illustrated in the lecture and during practical