HANDOUT – Components Objective 101.02

What are all the things on a motherboard?

The motherboard (MB) is the main circuit board in a PC. Everything inside and outside of a computer connects or interfaces with the motherboard in some way. The circuitry that makes up this main circuit board starts with all of the chips and slots installed into the board. All of these individual pieces are permanently connected to the motherboard using an electrically conductive material called solder (pronounced: sodder). Once they are connected to the motherboard, each of these pieces become motherboard components. The components are connected to each other with the little lines on the board, which are called traces. Traces work together to make up groups of electronic circuits between the components, which are called busses. Different bus architectures (e.g., AGP, PCI, PCIe, etc.) carry data through the computer system, connecting all the devices/components of the computer. These busses work differently, but they all have the same basic function already noted. There are two types of motherboard components: Integrated and Expansion components. CPU sockets

Each MB must have a main processor called the or CPU. A CPU plugs into a socket soldered onto the motherboard. Because the CPU socket is physically part of the motherboard, that means it is integrated into the MB. The CPU and MB have to be matched, much like light bulbs in a socket, which have to match in shape and voltage in order to work correctly, CPUs also have to match the shape and voltage of the socket they are being installed into. Installing a CPU is made very easy by the use of Zero Insertion Force or ZIF sockets. ZIF sockets are designed with a lever that is rotated up, “opening” the socket. Once the ZIF is open, a CPU can be installed into the socket, then the lever is rotated down, locking

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HANDOUT – Motherboard Components Objective 101.02

the CPU into place. Matching CPU to Socket

CPU sockets come in three basic types: the slot, the or PGA and the land grid array or LGA. Each CPU must match the MB’s socket, and each MB must match the CPU. DIMM Slots

The dual inline memory module or DIMM slots on a MB are extremely important to the motherboard’s operation. DIMM slots are where RAM modules are installed. The motherboard will not function without RAM modules installed into the DIMM slots.

Before DIMM slots there were single inline memory modules or SIMMs, but those are no longer being made or supported by modern computers. Hard Drive, Optical Drive, and Floppy Disk Drive Controllers

In order to store data and have access to that data, have to connect to data storage devices like hard disk drives, optical disk drives and floppy disk drives. These connectors are referred to as “controllers” because they contain the circuitry that controls when and how the MB “talks” to the storage devices. The types of integrated storage drive controllers found on motherboards are IDE, SATA and Floppy.

PATA (aka EIDE or IDE) or Parallel ATA is a 40-pin connector. Modern MBs only contain one single PATA controller. Each controller can support two PATA devices, a master and a slave. Jumpers on the devices are used to set the device as master or slave.

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HANDOUT – Motherboard Components Objective 101.02

SATA controllers are small L-shaped connectors. SATA data cables are smaller, so they allow for better air flow and thus better cooling. Most modern motherboards have multiple SATA ports

Floppy controllers have 34-pin connectors. Modern MBs might not contain a FDD controller, but if they do, there would only be one.

Integrated Ins and Outs

Integrated Inputs and Outputs, or Integrated I/O ports, are the connectors that stick out of the back of the computer system case. They are called inputs and outputs because they allow data to flow in and out of the computer system. These ports allow for connecting devices to the motherboard externally or outside the system case.

These integrated I/O ports can include: - 1/8th inch audio ports (Mic, Headphone, Line in) - Network Interface Cards (NIC) – Marked LAN on drawing. - Video ports (VGA) – 15-pin female. Connects to monitor. - USB (Universal serial Bus) - Firewire (IEEE 1394) - Parallel port – used most often for printers – 25-pin female port. Parallel cables transmit data 8 bits at a time. - Serial Port – aka COM port - 9-pin male. Serial cables transmit data 1 bit at a time. - PS/2 – mini-DIN mouse and keyboard ports. - eSATA port (External SATA) - Modem – not pictured. Used for dial-up modems.

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HANDOUT – Motherboard Components Objective 101.02

Notes on these interfaces:

1. USB can be USB 1.1 (maximum speed of 12 Mbps) or USB 2.0 (maximum speed 480 Mbps). USB 2.0 is backward compatible with USB 1.1, but USB 2.0 devices will run at the speed of the USB 1.1 port. 2. Modem ports have the same shape as NIC/LAN ports but are smaller since they will accept an RJ-11 connector for a telephone cable (4 wires) instead of an RJ-45 connector for a network cable (8 wires). 3. Modem expansion cards that are placed in separate expansion slots have a standard configuration of two RJ-11 ports.

Front Panel Connections

Motherboards also supply physical connections for the buttons, lights, switches, speakers and I/O ports on the front of all system cases. These connections show up as sets of pins near the edge of the motherboard. By connecting wires to the pins, the front panel connectors allow the power and reset buttons to control power. They also connect lights called LEDs or light emitting diodes to show power and hard drive activity. If the system case front panel contains I/O ports like Audio, USB and Firewire, they can be connected to the MB using these pins as well.

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HANDOUT – Motherboard Components Objective 101.02

Expansion Slots

There are a number of expansion card slots on every MB. These slots allow a user to add additional devices by inserting expansion cards into these slots. On a modern MB there will be several different types of expansion slots.

Older expansion slots include: AGP (Accelerated Graphics Port), PCI (Peripheral Component Interconnect), AMR (Audio Modem Riser) and CNR (Communication Network Riser). AMR and CNR slots are almost never found on motherboards today.

Newer motherboards (as of 2004) contain PCIe (Peripheral Component Interconnect Express) expansion slots, which have virtually taken over the need for AGP and certain PCI cards.

The expansion slots are connected to the other components using the expansion bus. Over time, there has been a progression of speed and transfer rate. With the old 8-bit ISA (Industry Standard Architecture), the speed was 4.77MHz. It was replaced by the EISA (Enhanced ISA), which had a 16-bit transfer ability.

Today’s computers often use PCI (32-bit at 33MHz). AGP is a high speed (66 MHz), single purpose slot used for connecting high performance graphic cards to obtain superior video to the monitor. Both of these busses are being replaced with the newer PCI Express bus system.

Laptops have slots on the sides of them that accommodate expansion cards called PCMCIA cards which provide for the installation of additional devices just like expansions slots do on desktop computers.

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