Understanding Storage Technologies
Introduction
Today's electronic systems require large-capacity, faster, and cost-effective storage solutions to meet the growing demands of data and complex system software. In this article, we will explore common storage types and their applications in various electronic systems. Additionally, we will present a practical storage example commonly used in smart electronic devices.
Background
Read-Only Memory (ROM): Pre-programmed with permanent firmware/data that cannot be changed, used for storing boot code in computer/microcontroller initialization.
Programmable Read-Only Memory (PROM): User-programmable memory, often referred to as one-time programmable (OTP) memory, utilizing fuse or anti-fuse technology. Anti-fuse creates a short connection instead of an open connection.
Electrically Erasable Read-Only Memory (EEPROM): User-erasable and reprogrammable memory, suitable for low-power applications and embedded systems.
FLASH: Non-volatile memory that can be erased and reprogrammed by the user. FLASH uses floating transistors to store data and offers faster erase and program capabilities.
Application
PROM: Used for security purposes like encryption key storage and anti-roll back protection in video streaming applications.
EEPROM: Ideal for low-power applications and persistent data storage in microcontrollers.
FLASH: Main storage unit in PCs and smart embedded devices.
Two types of FLASH
NAND Flash: Faster write speed, lower cost per bit, higher storage density, suitable for data storage applications.
NOR Flash: Faster read speed, lower write speed, higher cost per bit, lower storage density, ideal for code storage and execution.
Practical Storage Design in Electronic System
eMMC (embedded Multi-Media Controller): Half-duplex memory with an 8-bit wide I/O bus, slower read/write speed, used in consumer devices where storage latency is not critical.
UFS (Universal Flash Storage): Full-duplex memory with a 1-lane I/O interface, faster read/write speed (e.g., UFS3.0 has 8x read speed compared to eMMC 5.1), suitable for high-end devices like mobile phones requiring faster memory throughput.
Summary & Conclusion
Non-volatile memory retains data when power is lost.
ROM is pre-programmed and cannot be changed.
PROM can be programmed once by the user.
EEPROM allows user programming and reading.
NAND Flash has lower cost per bit and higher storage density.
NOR Flash has faster read speed and is suitable for code storage.
eMMC is half-duplex with slower read/write speeds, ideal for consumer devices.
UFS is full-duplex with faster read/write speeds, suited for high-end devices
In the ever-evolving landscape of technology, the need for large-capacity, faster, and cost-effective storage solutions is crucial. Various non-volatile memory types, including ROM, PROM, EEPROM, and FLASH, serve specific purposes in storing firmware, facilitating user-programmability, and enabling efficient data storage.
NAND Flash and NOR Flash offer distinct advantages in terms of cost, density, and read/write speeds, catering to different application requirements. eMMC and UFS, as integrated storage controllers, provide reliable solutions for consumer devices and high-end devices respectively.
Understanding memory characteristics and applications is essential for electronic system engineers to ensure optimal performance and seamless user experiences. Staying informed about advancements in storage technologies is vital for future innovations in electronic system design.