NOR flash memory

What does NOR flash memory mean?

NOR flash memory is a type of non-volatile memory (NVM) that enables the random access and Execution of code directly from the memory chip. Unlike traditional flash memory, which requires code to be copied into volatile memory before execution, NOR flash memory allows code to be Executed in-place, Enabling faster boot times and improved performance.

Applications

NOR flash memory is widely used in various applications, including:

• Embedded systems: NOR flash is ideal for embedded systems, such as automotive electronics, industrial controllers, and medical devices, where reliability and code execution speed are critical. It provides a rugged and high-performance storage solution for program code, configuration data, and firmware.
• Boot code storage: NOR flash is commonly used to store boot code and BIOS firmware in computers and other electronic devices. Its ability to execute code directly from memory enables rapid and reliable system startup.
• Code shadowing: NOR flash memory can be used to create ROM-like environments for code shadowing, a technique that copies program code from flash memory into high-speed volatile memory (such as SRAM) to improve system performance.

History

The development of NOR flash memory can be traced back to the 1970s, with significant advancements made in the 1980s and 1990s. Early flash memory designs relied on EPROM (Erasable Programmable Read-Only Memory) Technology, which required a high voltage to Erase specific memory cells.

In 1989, Intel introduced NOR flash memory, which used a lower voltage for erasing and a logical “NOR” operation for read access. This innovation enabled faster and more flexible memory operations, making NOR flash more suitable for code execution.

Throughout the 1990s, NOR flash memory underwent significant improvements in speed, density, and reliability. It gained popularity in the embedded systems market and became a standard for boot code storage in computing devices.

Today, NOR flash memory continues to evolve with the development of denser and faster technologies, such as quad-SPI (Serial Peripheral Interface) and Octal-XIP (Execute-In-Place) interfaces, further enhancing its performance and versatility in a wide range of applications.