MICROPROCESSOR: AN OVERVIEW

Microprocessor

• Central Processing Unit (CPU)– it controls and directs all activities of the computer

using both external and internal bus• CPU Manufacturers– Motorola– Advanced Micro Devices– Cyrix– IBM– Intel

CPU Architecture

• DIP (Dual In-Line Package)

• PGA (Pin Grid Array)

CPU Basic Structure

• Math Coprocessor – The math coprocessor is used to improve the

processor’s number-crunching speed

• Clock Speed – The clock speed is the frequency with which a

processor executes instructions• Cache Memory – Storage area for frequently used data and instructions

CPU Basic Structure• The Bus – The system board’s under lying circuitry. A bus allows all

devices to communicate with each other – External Bus (System Bus)

• It allows the processor to talk to another device– Data Bus

• Used to send and receive data. The larger the bus width, the more data can be transmitted

– Address Bus • The address bus also contains a set of wires to carry information in

and out of the processor, but the information the address bus sends is addressing information used to describe memory location

CPU Basic Structure

– The BIOS (Basic Input / Output System) Three major company that manufacture

ROM BIOS software• Phoenix Technology – pioneer• American Megatrends International (AMI)• Award Software

CPU Basic Structure (Memory)• DRAM (Dynamic Random Access Memory) DRAM is dynamic random access memory. This is actually is “RAM” that most people are talking about when they mention RAM. When you expand the memory in a computer, you are adding DRAM chips.• SRAM (Static Random Access Memory The “S” in SRAM stands for static. Static random access memory doesn’t require the refresh signal that DRAM does. The chips are more complex and are thus more expensive. • ROM (Read Only Memory) ROM – stands for read-only memory. It is called read-only because it can’t be written to. Once the information has been written to the ROM, it can’t be changed. ROM is normally used to store the computer’s BIOS, because this information normally does not change.

CPU Basic Structure (Memory)• CMOS (Complimentary Metal-Oxide Semiconductor) CMOS – is a special kind of memory that holds the BIOS configuration settings. CMOS memory is powered by a small battery so the settings are retained when the computer is shut off.• Hard Disk System Hard disk reside inside the computer and can hold more information than other forms of storage. The hard disk system contains three critical components: the controller, the hard disk, and the host adapter• Floppy Drives A floppy disk drive is a magnetic storage medium that use a floppy diskette made of a thin plastic encased in a protective casing..

Floppy Diskette Capacities

Floppy Drive Size Number of Tracks Capacity

5 40 360 KB

5 80 1.2 KB

3 80 720 KB

3 80 1.44KB

3 80 2.88 KB

CPU Basic Structure (Memory)• CD ROM Stands for Compact Disk Read Only Memory. Have been standardized across platforms with ISO 9660 standard. ISO – International Organization for Standardization • DVD ROM Digital Versatile Disk• USB Flash Drive

Universal Serial Bus.