Edge AI devices are everywhere—smart cameras, industrial sensors, in-vehicle systems, and wearables. These devices share common requirements: they must boot instantly, consume minimal power, and operate reliably for years.
Traditional approaches copy code from a flash memory into RAM before execution. This adds boot delay, consumes precious RAM, and increases power consumption—three factors that edge AI can hardly afford.
Execute in Place (XIP) offers a better way. With XIP, the CPU executes code directly from the flash memory without copying it to RAM. This article explains how XIP works, why NOR Flash is the natural choice for XIP, and how it brings real benefits to edge AI applications.
XIP stands for Execute in Place. It allows a processor to fetch and execute code directly from a non-volatile memory (like NOR Flash) as if it were executing from internal RAM.
Why NOR Flash is ideal for XIP:
Random access – NOR Flash provides byte‑addressable random read access, just like RAM.
No erase required for reads – Reading data from NOR Flash does not require a preceding erase operation.
Direct connection – NOR Flash can be connected directly to the CPU’s address and data buses (or via SPI/QSPI with memory‑mapped support), enabling the CPU to fetch instructions seamlessly.
Contrast with NAND Flash: NAND Flash is page‑oriented and requires bad‑block management and error correction. It cannot be memory‑mapped, making it unsuitable for XIP.
Edge AI devices often need to respond immediately upon power‑up. With XIP, the processor can start executing the boot code directly from NOR Flash in microseconds, eliminating the delay caused by copying code to RAM. This is critical for safety‑critical systems like automotive displays or industrial controllers.
RAM is a scarce resource in embedded systems. By executing code directly from flash, the entire code space does not need to occupy RAM. This frees up RAM for AI models, data buffers, and runtime stacks—allowing you to use a smaller, less expensive MCU or allocate more memory to your machine learning workload.
Without XIP, you typically need a multi‑stage bootloader to copy code from flash to RAM. XIP eliminates this complexity, reducing BOM cost and software development effort. It also improves system reliability because there are fewer stages where boot failure can occur.
A vibration sensor running a TinyML model detects anomalies in industrial machinery. The firmware and model are stored in a 256Mb NOR Flash supporting XIP. The MCU executes the code directly from flash, leaving the entire internal RAM for the inference buffer. Boot time is under 100 ms, and the device consumes minimal power during operation.
In a digital dashboard, the instrument cluster must display critical information the moment the ignition is turned on. Using a parallel NOR Flash with XIP, the boot code executes directly, achieving a “zero‑delay” startup. The system meets automotive grade requirements and simplifies software architecture.
An industrial controller requires extreme reliability—any boot failure could lead to production downtime. XIP eliminates the risk of RAM corruption during boot. A NOR Flash with industrial temperature range (-40°C to +85°C) ensures stable operation in harsh environments.
When choosing a NOR Flash for XIP in edge AI applications, consider the following parameters:
| Parameter | Considerations |
|---|---|
| Interface | SPI / Quad SPI / Parallel – ensure your MCU supports memory‑mapped mode for SPI/QSPI. |
| Read Speed | Look for low read latency and high clock frequency (e.g., 133 MHz for Quad SPI). |
| Capacity | Sufficient to store your firmware, AI model, and any read‑only data. |
| Temperature Grade | Industrial (-40°C to +85°C) or automotive for harsh environments. |
| Reliability | Data retention (typically 20+ years) and endurance (100k+ erase cycles). |
Example: The IS26KL256S-DABLI00 is a 256Mb parallel NOR Flash with industrial temperature support, offering fast random access and XIP capability—ideal for MCU‑based edge AI designs.
Myth 1: XIP is slower than executing from RAM.
Fact: Modern NOR Flash devices can achieve very high read speeds (e.g., 133 MHz Quad SPI). For many applications, the difference is negligible, especially when the code cache is enabled.
Myth 2: All NOR Flash supports XIP.
Fact: While most parallel NOR Flash supports XIP, not all SPI/QSPI NOR Flash do. Check whether the device supports memory‑mapped mode (often called “XIP mode”) and verify the timing with your MCU.
Myth 3: XIP increases power consumption.
Fact: XIP can actually reduce power because you avoid the energy needed to copy code to RAM. Moreover, many NOR Flash devices offer deep power‑down modes when not in use.
XIP is a powerful technique that enables edge AI devices to boot faster, use less RAM, and simplify system design. By choosing a NOR Flash designed for XIP—such as the IS26KL256S—you can build more efficient and reliable products that meet the demands of modern edge computing.
Whether you are developing a TinyML sensor, an automotive display, or an industrial controller, leveraging XIP can give your product a competitive edge.
Our engineering team specializes in memory selection for edge AI and industrial applications. We offer:
Free technical consultation – we’ll help you match the right NOR Flash to your MCU and application.
Free samples – test the IS26KL256S or other parts in your own design.
Stock availability – we maintain deep inventory for long‑term production.
Contact us today to discuss your project or request samples.