 Central Processing Unit(CPU) Central Processing Unit(CPU)  Components of the CPU Components of the CPU  Actions Performed by CPU Actions Performed by CPU  CPU REGISTERS CPU REGISTERS  MOTHER BOARD MOTHER BOARD  CONROL UNIT(CU) CONROL UNIT(CU)  ARITHMETIC AND LOGIC UNIT(ALU) ARITHMETIC AND LOGIC UNIT(ALU)

 The part of the computer performs the bulk of data processing operations is called the central processing unit.  Central processing unit etched on silicon chip called microprocessor.  Contain tens of millions of tiny transistors.

The central processing unit (CPU) of a computer is the main unit that dictates the rest of the computer organization.  Register set: Stores intermediate data during the execution of instructions.  Arithmetic logic unit (ALU): Performs the required micro- operations for executing the instructions.  Control unit: supervises the transfer of information among the registers and instructs the ALU as to which operation to perform by generating control signals. CONTINUE....

Central Processing Unit = “brain” Executes programs by: –Fetching and decoding the next instruction from memory –Execute it Consists of: –Control Unit –Arithmetic Logic Unit (ALU) –Registers (high-speed memory) Program Counter (PC) Instruction Register (IR) DiskPrinter Main Memory Control Unit Registers Arithmetic Logic Unit Bus I/O Devices

Fetch cycleCPU: Fetches an instruction from primary storage Increments a pointer to location of next instruction Separates instruction into components (instruction code and data inputs) Stores each component in a separate register Execution cycle ALU: Retrieves instruction code from a register Retrieves data inputs from registers Passes data inputs through internal circuits to perform data transformation Stores results in a register

 Hold intermediate results and frequently needed data items  Used only by currently executing program  Implemented within the CPU, contents can be read or written quickly  Increasing their number usually decreases program execution time to a point  Store information about currently executing program and about status of CPU Continue…..

Intel and Advanced Micro Devices (AMD) are the two largest manufacturers of CPU’s. Intel is substantially larger than AMD but they both make CPU’s found commonly in computer systems.

A motherboard is the physical arrangement in a computer that-  Contains the computer’s basic circuitry and components. On the typical motherboard, the circuitry is imprinted or affixed to the surface of a firm planar surface and usually manufactured in a single step.

Control unit controls operations of other parts of CPU as well as all parts of computer by sending a control signal, for example  control sequence of instructions to be executed  Control flow of data among all parts of computer  Interpret  Instructions  Regulate timing of processor  Send control single to and receive control single from peripheral devices.

Arithmetic and logical unit consists of a complicated set of logic circuit and accumulator. It is mainly responsible for-  Calculation  Logical comparison and decision