In embedded systems and industrial computing, ARM core boards serve as the “central brain,” integrating key modules such as processors, memory, and storage. Among these, RAM (Random Access Memory) and NAND Flash play distinct roles—RAM handles runtime operations, while NAND Flash manages persistent storage. This article explores their differences and collaboration from architectural, performance, and application perspectives.
RAM (Random Access Memory) RAM is a volatile memory that loses data when powered off. It’s primarily used for runtime data caching, variable storage, and stack management—essentially the system’s “workspace.”
NAND Flash NAND Flash is a non-volatile memory that retains data after power loss. It stores system firmware (e.g., bootloader, kernel, rootfs), configuration files, and user data—acting as the system’s “warehouse.”
| Feature | RAM | NAND Flash |
|---|---|---|
| Data Persistence | Volatile, data lost on power-off | Non-volatile, data retained |
| Read/Write Speed | Extremely fast (nanoseconds) | Fast read, slower write (block erase required) |
| Access Method | Random access | Block erase + page write |
| Endurance | Unlimited | Limited (approx. 10K–100K cycles) |
| Cost & Capacity | Higher cost, smaller capacity | Lower cost, larger capacity |
| Typical Use | Program execution, cache, stack | Firmware, system image, user data |
ARM core boards typically follow this workflow:
Boot Process: On power-up, the CPU reads the bootloader from NAND Flash and loads the kernel and file system into RAM.
Runtime: Programs execute in RAM, which handles data processing and caching, while Flash retains original data.
Data Storage: Logs, configurations, and user data are written to NAND Flash, with RAM serving as a temporary buffer.
This “Flash for storage, RAM for execution” architecture ensures both high performance and data persistence.
RAM Applications:
RTOS task scheduling
Frame buffering in image processing
Packet caching in network stacks
NAND Flash Applications:
Storing Linux images (e.g., uImage, rootfs)
Saving device configurations and calibration parameters
Logging runtime data and user files
| Application Type | Recommended Configuration | Description |
|---|---|---|
| Lightweight Controllers / IoT Gateways | 64MB RAM + 128MB NAND Flash | Uses external storage to replace NAND, offering low cost and high flexibility. |
| Industrial Control Boards / HMIs | 256MB NAND + 256MB DDR3 | Built-in storage for greater reliability, suitable for harsh environments. |
| AI Edge Nodes / Smart Terminals | 1GB+ DDR3/DDR4 + eMMC | Meets demands for high computing power and fast data processing, supporting complex algorithms. |
When designing ARM core boards, RAM and NAND Flash should be configured based on application needs:
Lightweight control systems: 64MB RAM + 128MB NAND Flash
Image processing or edge computing: ≥512MB RAM + ≥1GB NAND Flash
Industrial gateways or protocol converters: Consider Flash endurance and RAM multitasking capability
You may also optimize with technologies like eMMC, SPI NOR/NAND, DDR3/DDR4.
RAM and NAND Flash are indispensable components of ARM core boards. RAM powers efficient execution, while NAND Flash ensures secure data storage. Understanding their differences and synergy is key to building stable, high-performance embedded systems.
