Introduction to Computer Organization and CPU Architecture

Course: SIT 108

Lecturer: Dr. Daniel MakupiInstitution: Murang'a UniversityFocus: Computer organization and CPU architecture

Organization of a Microprocessor-Based System

Key Elements

This section introduces the basic structure and architecture of a microprocessor-based system, highlighting the critical interaction between components and their roles.

Components of a Microprocessor-Based System

Main Components

• Microprocessor:

  • The central processing unit (CPU) that executes instructions by performing arithmetic and logical operations.

  • Operates at high speed, coordinating all actions within the computer system.

• Input Devices:

  • Components such as keyboards, mouse, and sensors used to enter data into the system.

  • Facilitate user interaction and data entry.

• Output Devices:

  • Components that present processed data to the user, including monitors, printers, and speakers.

  • Convert digital data into human-readable formats.

• Memory:

  • Encompasses Read/Write Memory (R/W Memory), which allows for data and instructions to be stored and modified, and Read-Only Memory (ROM), which retains permanent data.

• Communication Path (Bus):

  • A set of physical connections (wires) through which data and signals are communicated among components.

  • Essential for data transfer between the CPU, memory, and peripheral devices.

These collective components form what is known as a microcomputer system.

Peripheral Devices

Definition and Roles

• Peripheral: Refers to devices that provide input/output functionality, which can be external to the microprocessor.

• Key components include:

  • Microprocessor: Core processing unit.

  • Input Devices: For data entry.

  • Output Devices: For displaying results.

  • ALU (Arithmetic Logic Unit): Performs arithmetic and logical operations.

  • Register Array: Contains registers for temporary storage.

  • System Bus: Facilitates communication between components.

  • Control Unit: Directs the operation of the processor.

  • ROM: Stores firmware and essential programs.

  • R/W Memory: User memory for data storage.

Microprocessor Description

Characteristics

• The microprocessor is a semiconductor device implemented with electronic logic circuits to process data.

• Manufacturing Technologies:

  • Designed using LSI (Large Scale Integration) or VLSI (Very Large Scale Integration) techniques, allowing a high density of components on a single chip.

• Functionality:

  • Integrates all necessary logic circuitry, including the control unit, the ALU, and registers.

Segmentation of the Microprocessor

Clear Segments

• The microprocessor architecture comprises three primary segments:

  • ALU (Arithmetic Logic Unit): Handles all arithmetic and logical operations.

  • Register Array: Includes a collection of registers that temporarily hold data during processing.

  • Control Unit: Coordinates the actions of the processor and manages the execution of instructions.

Functions of the ALU and Register Array

ALU

• Computing Functions:

  • Executes arithmetic functions (addition, subtraction) and logic operations (AND, OR, XOR).

  • Results generated by the ALU are stored either in registers or moved to memory.

• Register Array:

  • Comprises general-purpose and special-purpose registers, utilized for temporary data storage and instruction execution.

  • Some registers may be user-accessible through specific instructions, allowing manipulation of data directly in the CPU.

Control Unit and Output Section

Control Unit

• Responsible for generating timing and control signals that govern the microcomputer’s operations.

• Oversees data movement between the microprocessor, memory, and peripheral devices.

Output Section

• Transfers processed data to output devices. Possible outputs may include:

  • Light Emitting Diodes (LEDs) for visual displays

  • Cathode Ray Tubes (CRTs) for older display technologies

  • Printers for hard copy output

  • Networking communication to other computers for data sharing.

Role of Memory

Memory Functions

• Memory serves a vital role in storing binary information, which includes both data and instructions needed for program execution.

• It supplies the microprocessor with instructions from where it will perform operations in the ALU.

• The results from operations may either be sent immediately to the output section or stored for later use.

Memory Structure

Memory Block

• Reinforces the critical functions of memory for both instruction and data storage.

• Highlights memory's importance in supporting program execution alongside the ALU, providing help to augment performance and control.

Read-Only Memory (ROM)

Functions of ROM

• ROM retains permanent data and programs that do not require alteration.

• Typically stores essential monitoring programs or firmware for initial boot processes of microcomputers.

• Facilitates device interpretation, converting information from components like keyboards into binary data for processing by the microprocessor.

• Data stored in ROM is readable but not alterable by the user.

Read/Write Memory (R/W Memory)

Characteristics and Use

• Also referred to as user memory, this memory type allows users to store programs and data that may change throughout operation.

• Facilitates both reading and writing, enabling easy modification of information as required during system operation.

• Includes the monitor program of single board computers, responsible for managing data inputs from user interfaces such as Hex keys and maintaining this information in R/W Memory.

System Bus

Definition and Functionality

• The system bus serves as the communication pathway between the microprocessor and peripheral devices.

• Consists of multiple conductors (wires) designed to carry bits of information.

• Although multiple peripheral devices may be connected, the microprocessor communicates with each peripheral sequentially.

• The control unit manages timing to synchronize data exchanges between the CPU and peripherals.