Monday, February 15, 2016

Microcomputer System Architecture

Blocks of Microcomputer System

Microcomputer System Architecture

CPU consists of
  • Registers for the temporary storage of information
  • ALU for performing operations on this information
  • Instruction decode and control unit that determine the operation to perform
  • Instruction Register (IR) holds the binary code for each instruction as it is executed
  • Program Counter (PC) holds the memory address of the next instruction to be executed
  • Read Write memory. It is volatile.
  • User program and data are loaded in to RAM for execution
  • Read only memory. It is non-volatile
  • Is used to hold software routines that perform input/output operations
  • Unidirectional Address Bus to point memory location
  • Bidirectional Data Bus to read/write data in memory
  • Control Bus to generate read, write and synchronization signals
Interface Circuits
  • Provide circuitry to connect peripheral devices
Peripheral Devices
  • Human interface device like keyboard, mouse, printer, etc.
  • Storage device like hard disk, optical disks, USB, etc.
  • Control and Monitor devices
  • Input / Output Subroutines: Directly manipulate the hardware of the system
  • Operating System for managing hardware resources
  • Application Software: User interface
Fetching and Executing Instructions:
Fetching Steps
  • The content of PC are placed on the address bus
  • A Read signal is activated
  • Data (instruction opcode) are read from RAM and placed on data bus
  • The opcode is latched into the CPU’s IR
  • The PC is incremented to prepare for the next fetch from memory
Executing Steps
  • Decoding the opcode and generating the control signals to gate internal registers in and out the ALU and to signal ALU to perform the specified operation.

Related topics:
Microcomputer System   |   Numbering System   |   Memory Basics   |   Digital Logic   |   ASCII Code   |   Computer Internals   |   ROM and RAM Memory

List of topics: Microcomputer

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