RAM and ROM Memory Overview
RAM and ROM Memory Overview
Introduction
Types of Memory
RAM Memory
ROM Memory
Hybrid Memory
Types of Memory
RAM Memory
SRAM-Static Random-Access Memory
DRAM - Dynamic Random-Access Memory
SRAM
SRAM Internal Structure
SRAM Memory
Fastest type of memory
Low density
More expensive
Generally used in small amounts (L2 cache) or expensive servers
DRAM Memory
DRAM Internal Structure
Types of DRAM
SDRAM - Synchronous dynamic RAM
DDR RAM - Double data rate RAM
DDR2 RAM
DDR3 RAM
DDR4 RAM
DRAM Memory Very high density
Cheap data cache in computers
Must be periodically refreshed
Slower than SRAM
Volatile
DDR Internal Structure
Row 1 Row 2 Row 3 Row 40
2
4
6
8
10
12
Column 1Column 2Column 3
DDR2 Internal Structure
DDR3 Internal Structure
DDR Comparison
DDR3 and DDR4 Review
DDR4 Memory
SRAM Memory Interface
SDRAM Memory Interface
DDR Memory Inreface
SRAM vs DRAM
SRAM is faster compared to DRAM
SRAM consumes less power than DRAM
SRAM uses more transistors per bit of memory compared to DRAM
SRAM vs DRAM Cont.
SRAM is more expensive than DRAM
Cheaper DRAM is used in main memory while SRAM is commonly used in cache memory
DRAM Required Refresh cycle
DRAM Required EDC Circuit
ROM Memory
Mask ROM - Mask Read Only Memory
PROM - Programmable Read Only Memory
EPROM - Erasable Programmable Read Only Memory
PROM Memory
ROM Memory
Programmable by special program tools/modes
Read only memory during normal use
Non-volatile
EPROM uses UV light to reset all bits
Hybrid Memory
Flash Memory
NVRAM - Non-volatile random-access memory
EEPROM - Electrically Erasable Programmable Read-Only Memory
Flash Memory
NAND Flash Memory
NOR Flash Memory
Flash Memory Architecture
NAND Flash Memory
NAND Flash
NAND vs NOR Flash
NAND and NOR Pins
Selection Check Point Most writes must be preceded by an erase
operation
NAND has smaller erase units for fewer erases in less time
NOR is an XIP device
NAND Flash Memory
NAND Flash
NAND Flash
NAND Memory Interface
Memory Mapping in NOR Flash
NOR Flash Interface
Memory Mapping in NOR Flash
Any Questions
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