Presentation1

Views:
 
Category: Education
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

PowerPoint Presentation:

Read only memory By Yadnesh n. gawde

PowerPoint Presentation:

The term " memory " applies to any electronic component capable of temporarily storing data. There are two main categories of memories: Internal memory that temporarily memories data while programs are running. Internal memory uses micro conductors, i.e. fast specialized electronic circuits. Internal memory corresponds to what we call random access memory (RAM). Auxiliary memory (also called physical memory or external memory ) that stores information over the long term, including after the computer is turned off, It’s know as read-only memories . INTRODUCTION OF MEMORY

PowerPoint Presentation:

RAM ROM Stands for: Random Access Memory Read-only memory Volatility: It is volatile It is non - volatile Types: The two main types of RAM are static RAM and dynamic RAM. The types of ROM include PROM, EPROM and EEPROM. Use: RAM allows the computer to read data quickly to run applications. ROM stores the program required to initially boot the computer. Definition: RAM is a form of data storage that can be accessed randomly at any time, in any order and from any physical location. ROM is also a form of data storage that can not be easily altered or reprogrammed. WHY ROM IS BETTER THAN RAM

PowerPoint Presentation:

ROM holds programs and data permanently even when computer is switched off Data can be read by the CPU in any order so ROM is also direct access The contents of ROM are fixed at the time of manufacture Access time of between 10 and 50 nanoseconds Read Only Memories (ROM) or Programmable Read Only Memories (PROM) have: N input lines, M output lines, and 2 N decoded minterms Introduction of Read only memory (ROM)

PowerPoint Presentation:

Types of ROM 1. Programmable Read Only Memory (PROM ) 2. Erasable Programmable Read Only Memory (EPROM) 3. Electrically Erasable Programmable Read Only Memory (EEPROM)

PowerPoint Presentation:

Types of ROM Empty of data when manufactured May be permanently programmed by the user 2. Erasable Programmable Read Only Memory (EPROM) Can be programmed, erased and reprogrammed The EPROM chip has a small window on top allowing it to be erased by shining ultra-violet light on it After reprogramming the window is covered to prevent new contents being erased Access time is around 45 – 90 nanoseconds 1. Programmable Read Only Memory (PROM)

PowerPoint Presentation:

Types of ROM Reprogrammed electrically without using ultrav ligioletht Must be removed from the computer and placed in a special machine to do this Access times between 45 and 200 nanoseconds 3. Electrically Erasable Programmable Read Only Memory (EEPROM)

PowerPoint Presentation:

Example: A 8 X 4 ROM (N = 3 input lines, M= 4 output lines) The fixed "AND" array is a “decoder” with 3 inputs and 8 outputs implementing minterms. Read Example: For input (A 2 , A 1 , A 0 )= 001, output is (F 3 ,F 2 ,F 1 ,F 0 ) = 0011. Read Only Memory Example D7 D6 D5 D4 D3 D2 D1 D0 A2 A1 A0 A B C F 0 F 1 F 2 F 3 X X X X X X X X X X

PowerPoint Presentation:

THANK YOU