Chapter 5: Introduction to Microprocessor

Chapter 5: Introduction to Microprocessor

1. Overview

   • Microcomputer
     • A complete computer on a smaller scale and is generally a synonym for the more common term,(PC).
     • Microcomputer Components
       • Input devices
       • Processing components
       • Storage devices
       • Output devices
       • Communication and network devices
       • Other hardware components
   • Microprocessor (abbreviated µP)
     • A programmable digital electronic component that incorporates the functions of a central processing unit (CPU) on a single semiconducting integrated circuit (IC)
   • Microprocessor & Microcontroller
     • Microcontroller
       • Incorporate RAM, ROM and I/O resources internal to the chip
         • E.g.: PIC16F877A
       • Perform a small set of specific functions
         • Modern cars: performs a dedicated task, i.e. to regulate the brakes on all four wheels, air conditioning, cruise control
     • Microprocessor
       • Require external components : RAM, ROM and I/O.
         • E.g.: Intel's 80186 & 80386
       • Perform a wider set of general purpose functions
         • E.g.: PC: performs necessary calculations for a very wide set of software applications, I/O for the main sub-systems, peripheral control etc.

2. Evolution of Microprocessor;

   • Faster and more efficient performance which improves each year
   • Not just computing but also from retail and industry to agriculture and vehicle safety
   • Since 1971, it has become the brain of literally millions of devices
   • Without the microprocessor they would not have existed-Intel

3. Microprocessor System

   • Basic microprocessor system consist of a Central processing unit (CPU), memory (RAM and ROM), input/output (I/O) unit.
   • A program stored in memory provides instructions to the CPU to perform an action
   • CPU fetch these instructions from memory and execute it.
   • To perform the actions of fetch & execute, all CPU are equipped with resources as following
     • Registers
       • To store info temporarily.
       • can be 8 bit, 16 bit, 32 bit and 64 bit registers (depending on the CPU. The bigger the better but increase the CPU cost).
     • ALU
       • Perform arithmetic functions2
     • Program counter
       • To point to the address of the next instruction to be executed 3
     • Instruction decoder / dictionary
       • Interpret the instruction (what steps the CPU should taken upon receiving a given instruction)
     • Bus
       • Address bus-transfer the address data code to memory or devices
       • Data bus-transfer data to/ from the CPU
       • Control bus-Control all the activities of the elements

4. Types of microprocessor

   • General Purpose Processors
   • Microcontrollers
   • Digital Signal Processors
   • 2 basic types of hardware are
     • Complex Instruction Set Computer (CISC)-can perform complex functions with one instruction.
       • can perform complex functions with one instruction.
       • The Intel Pentium and Atom chips are based on the CISC architecture.
     • Reduced Instruction Set Computer (RISC)-usually need multiple instructions.
       • usually need multiple instructions.
       • PowerPC and ARM’s Cortex chips are RISC systems
   • Microprocessor Performance (Performance specifications include)
     • clock frequency
     • addressable memory
     • the no. of cores