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Memory device

Introduction Memory Cell Memory Word Byte Capacity Address Read

Operation Write

Operation Access Time Volatile

Memory

Random-Access Memory (RAM)

Sequential-Access Memory (SAM)

Read/Write Memory (RWM)

Read-Only Memory

Static Memory Device

Dynamic Memory Device

Internal Memory Mass Memory

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General Memory Operation

Select the address. Select R/W operation. Supply the input to be store (W

operation). Hold the output data comings from

memory (R operation). Enable (or Disable) the memory

Example Memory chip 2K x 8. How many total bits

can chip store?2K = 1 x 1024 = 2048 words

1 word = 8 bits2K x 8 = 2048 x 8 = 16384 bits

Which memory store the most bits: 5M x 8, 1M x 16

5M x 8 = 5 x 1,048,576 x 8 = 4,1943,040 bits1M x 16 = 1,048,576 x 16 = 1,677,7216 bits

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CPU- Memory connections

Write operation1. CPU ๐Binary address

on address bus.2. CPU ๐Data on data

bus.3. CPU ๐control signal.4. ICs decode address

location.5. Transfer data to the

selected location.

Read operation1. CPU ๐Binary address on address bus.2. CPU ๐control signal.3. ICs decode address location.4. Place data ๐ data bus ๐ Transfer data to CPU

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Read-Only Memory

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ROM architecture

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ROM timing read operation

PROMs fusible links

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Structure of a bipolar MROM(Mask-Programmed )

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Example of a programmable logic device

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PROM architecture for PLDs

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PAL architecture

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Cell arangement in 16Kx1 DRAM

Symbolic representation of DRAM

Symbol & mode table for 6264 SRAM

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