CP1610: Introduction to Computer Components The Motherboard

What is the Motherboard? The largest circuit board in a computer. The means by which all devices are connected to each other, and the CPU. Also called the system board.

Parts on a Motherboard

What is the CPU Central Processing Unit. Also called the processor or the microprocessor. The most important chip in the computer. The brain, or command centre.

Parts of the CPU Input/output (I/O) unit Arithmetic logic unit(s) (ALU) Control unit

How the CPU Works

The I/O Unit is like the security guard at the front gate. Parking (Registers) 10 9 ALU ALU You need to go to Building 10! Parking (Internal Cache) The Control Unit (CU) is like a security guard directing students to the correct building. Please wait until the road is clear, and I will open the gate! The I/O Unit is like the security guard at the front gate.

CISC vs. RISC Processors Complex Instruction Set Code RISC Reduced Instruction Set Code

CISC RISC Karwa

Other Parts on the Motherboard System Bus CMOS BIOS The Chipset System Clock Expansion Slots Floppy and Disk Drive Connections Memory

System Bus Metal lines (traces) connecting parts on the motherboard. Allow data to travel between devices and the CPU. Like a system of roads throughout a city. Can be expanded to other parts (like highways connecting towns and cities).

CMOS Chip that saves your system settings: Date and time Hardware configuration Boot device order Has a battery so that it can save your settings even when the computer is off CMOS stands for Complex Metal Oxide Semiconductor

BIOS Basic Input/Output System Stores basic instructions on how the computer can talk to: Keyboard Mouse Monitor Memory Allows a computer to operate basic functions without any other software installed Is the same for ALL computers.

The Chipset The chipset controls most parts of the computer. It handles ‘routine’ work, so the CPU can handle more important processing. Some of the chips in the chipset include: Interrupt Controller Keyboard Controller DMA Controller

The Interrupt Controller What is an Interrupt? Lots of devices want to get the CPU’s attention; An interrupt is a signal that tells the CPU which device is calling, or sending data; The Interrupt Controller is a chip that controls the flow of data on the system bus, and lets the CPU know which device needs it;

Don’t worry… I can direct traffic for you! Who is trying to call me? This better be important! The CPU (Everyone wants his attention!) Don’t worry… I can direct traffic for you! The Interrupt Controller is like a police offer directing traffic at a busy roundabout. Some devices get priority over others

How the Interrupt Controller Works CPU 1 2 3 4 5 7 6 8 9 11 10 13 12 14 15 System Clock Keyboard Floppy PS/2 Mouse Interrupt Controller

Common Interrupt Requests (IRQ’s) USUAL FUNCTION/DEVICE System Timer 1 Keyboard 2 2nd IRQ controller 3 COM2: 4 COM1: 5 Free (used by LPT2: or sound card) 6 Floppy disk 7 LPT1: 8 Real Time Clock (RTC) 9 Free (may be labeled/appear as IRQ 2) 10 Free (often used by sound cards) 11 Free 12 PS/2 mouse 13 Math coprocessor on CPU (used) 14 Primary IDE 15 Secondary IDE Common Interrupt Requests (IRQ’s)

Keyboard Controller The Keyboard Controller provides the following functions: Keyboard Control and Interpretation. PS/2 Mouse Support. Access to the High Memory Area. The Keyboard Controller is often not needed in newer computers.

The DMA Controller Direct Memory Access Sometimes devices may want to ‘talk’ to each other without ‘going through’ the CPU. DMA Controller controls access to the system bus, and RAM, and bypasses the CPU.

The CPU (Not everyone needs his attention!) I’m busy with official business… don’t bother me! The CPU (Not everyone needs his attention!) This better be important if you want to keep going down Madinat Khalifa! Thanks, officer. I guess I don’t need to bother with this car! Don’t worry, Sarge! I’ll direct this car through the roundabout! I’m only going to McDonald’s! Do I really need to go see the CPU first? Beep! Beep! The Interrupt Controller The DMA Controller is like a second traffic officer who handles traffic not going to the CPU Can I go now? Some devices don’t need to talk to the CPU

The System Clock Crystal that emits a pulse/signal. Acts like a drummer in a rock band. Pulses provide timing for the CPU and other devices.

Clock Speeds Measured in Hertz Speed of the Motherboard: Cycles per second Speed of the Motherboard: Megahertz (MHz) Speed of the CPU: Gigahertz (GHz)

Expansion Slots Allow you to ‘expand’ the capabilities of your computer. Connect new circuit boards to your motherboard. Connect the data buses (roads) on the expansion cards to the system bus (roads) on the motherboard.

Common Expansion Cards Sound Cards Modems Network Cards Video Cards Specialty Cards

Types of Expansion Slots ISA Industry Standard Architecture Older, ‘legacy’ cards PCI Peripheral Component Interconnect Newer, faster expansion cards AGP Accelerated Graphics Port

Floppy and Disk Drive Connections Special slots for ‘ribbon’ (data) cables. Allow you to connect: Floppy disk drives; Hard disk drives; CD/DVD drives; Zip disk drives; Etc…

Floppy Drives There is usually only one floppy disk drive connection. A floppy controller chip on the motherboard controls talking to, and fuctions of the floppy drive.

EIDE Connections Used to connect: Two connectors on the motherboard. Hard disk drives; CD/DVD drives; Two connectors on the motherboard. Each connector can connect two devices; Up to four EIDI devices can be connected;

Memory Devices Hold data and instructions. Types of Memory: System Memory; RAM; ROM;

System Memory 1 Megabyte (1 MB) Built into motherboard. Maximum memory that could be handled by: Older PC’s; New PC’s before system drivers and OS are booted; Hold data and instructions for: System drivers; Programs used by the user;

Anything above 1 MB Reserved for device drivers and system functions Available to the user for any software

RAM vs. ROM RAM Examples: ROM Example: Random Access Memory Stores data and instructions Volatile Examples: RAM chips CMOS ROM Read Only Memory Stores basic system settings Non-volatile Example: BIOS

Types of Motherboards Choice of motherboard affects: Capabilities and limitations of system; Type of computer case needed; Common types of motherboards: AT ATX Backplane

The AT Motherboard Smaller Used for classic Pentium CPU Uses SIMM RAM Uses P8 and P9 power connectors

The ATX Motherboard Faster Easier to install More power management features Uses DIMM RAM Has a PI power connector

Backplane Motherboards Actually built into the computer case. More difficult to make upgrades. Not as popular.