Memory device

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Memory device
Introduction

• 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

• Memory Cell
• Memory Word
• Byte
• Capacity
• Address
• Read Operation
• Write Operation
• Access Time
• Volatile 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
bits 2K 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 bits 1M x 16
1,048,576 x 16 1,677,7216 bits
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CPU- Memory connections
Write operation 1. CPU ?Binary address on
address bus. 2. CPU ?Data on data bus. 3. CPU
?control signal. 4. ICs decode address
location. 5. Transfer data to the selected
location.
Read operation 1. CPU ?Binary address on address
bus. 2. CPU ?control signal. 3. ICs decode
address location. 4. Place data ? data bus ?
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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Symbol mode table for 6264 SRAM
Cell arangement in 16Kx1 DRAM
Symbolic representation of DRAM
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