Chapter 12Memory Devices

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Introduction

Memory Terminology Memory Cell Memory Word Byte Capacity Density Address Read Operation Write Operation Access Time

Volatile Memory Magnetic Memory Random-Access Memory (RAM) Sequential-Access Memory (SAM) Read/Write Memory (RWM) Read-Only Memory (ROM) Static Memory Device Dynamic Memory Device Main Memory Auxiliary Memory

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

General Memory Operation Select the address in memory Select read / write operation Supply the input data (write) Hold the output data (read) Enable / disable the memory

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Address Inputs

The R/W Input

Memory Enable

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

CPU-Memory Connections

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Read-Only Memory (ROM)

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

The Read Operation

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

ROM Architecture Register

Array

Address Decoders

Output Buffers

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

ROM Timing

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Types of ROMs

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Mask-Programmed ROM

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Programmable ROMs (PROMs)

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Erasable Programmable ROM (EPROM)

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Electrically Erasable PROM (EEPROM)

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

CD ROM

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Flash Memory

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

The 28F256A CMOS Flash Memory IC

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

ROM Applications Firmware

Bootstrap Memory

Data Tables

Data Converter

Function Generator

Auxiliary Storage

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

RAM Architecture Read Operation Write Operation Chip Select Common I/O Pins

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Static RAM (SRAM)

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Static-RAM Timing Read Cycle

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Static-RAM Timing Write Cycle

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Actual SRAM Chip

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

JEDEC standard memory packaging

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Dynamic RAM (DRAM)

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Address Multiplexing

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

CPU address bus driving memory

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

DRAM Read/Write Cycles Read Cycle

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

DRAM Read/Write Cycles Write Cycle

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

DRAM Refreshing

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

DRAM Technology Memory Modules FPM DRAM EDO DRAM SDRAM DDRSDRAM SLDRAM DRDRAM

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Expanding Capacity

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Expanding Word Size

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

The END

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design

Summary Logic Circuits Flip-Flops Sequential Circuits Decoder / Encoder Multiplexer / Demultiplexer Adder, Magnitude comparator, etc. DAC / ADC Memories

Chapter 12 Memory DevicesINC222 Logic Theory and Digital Circuit Design