We hear related terms such as RAM, ROM, ARM, MCU and CPU in our daily work, but what exactly are they? What's the difference between them? RAM, ROM, ARM, MCU and CPU are commonly used terms and hardware components in computers and embedded systems. They have significant differences in functions, uses, and characteristics. Next, we will understand them one by one.

  1. RAM (Random Access Memory)

1.1 Basic concepts

RAM (Random Access Memory) is a memory used to store temporary data, allowing random reading and writing of data. The data in RAM will be lost after power failure, so it is mainly used for running data storage and temporary storage.


1.2 Features

Readable and writable: RAM supports fast data read and write operations.

Volatility: RAM data will be lost after power failure.

High speed: RAM has a high read and write speed and is suitable for the main memory of the computer.

1.3 Applications

Computer memory: used as the main memory of the computer to store the operating system, application programs and data being processed.

Embedded system: used to store data when the program is running.

  1. ROM (Read-Only Memory)

2.1 Basic Concepts

ROM (Read-Only Memory) is a memory that can only read data and is usually used to store firmware and program code. The data in ROM will not be lost after power failure, so it is suitable for storing data that does not need to be modified frequently.

2.2 Features

Read-only: ROM can usually only read data and does not support write operations (some types of ROM such as EPROM, EEPROM and Flash ROM can perform limited write operations).

Non-volatility: ROM data will not be lost after power failure.

Durability: Suitable for storing data that needs to be preserved for a long time.

2.3 Applications

Firmware storage: The firmware of a storage device, such as the BIOS of a computer or the boot code of an embedded system.

Embedded system: Used to store program code and data that cannot be modified or rarely modified.

  1. ARM (Advanced RISC Machine)

3.1 Basic Concepts

ARM is a processor design based on the Reduced Instruction Set Computing (RISC) architecture, developed and licensed by ARM Holdings. ARM processors are known for their high performance, low power consumption and wide application.

3.2 Features

RISC architecture: ARM processors use a reduced instruction set, with fewer instruction sets and efficient instruction execution.

Low power consumption: ARM processor design focuses on power optimization, which is very suitable for mobile devices and embedded systems.

Wide application: ARM processors are widely used in smartphones, tablets, embedded devices and Internet of Things (IoT) devices.

3.3 Applications

Mobile devices: The main processor of smartphones and tablets.

Embedded systems: The core processor in industrial control, consumer electronics and IoT devices.

  1. MCU (Microcontroller)

4.1 Basic concepts

MCU (Microcontroller Unit) is a monolithic integrated circuit that integrates a processor, memory (RAM and ROM) and peripherals (such as timers, serial communication interfaces, ADCs, etc.). MCU is used to control specific tasks in electronic devices.

4.2 Features

Highly integrated: MCU integrates processor, memory and multiple peripherals, simplifying system design.

Low power consumption: MCU design usually considers low power consumption and is suitable for battery-powered embedded devices.

Real-time control: MCU has real-time control capabilities and is suitable for applications that require timely response.

4.3 Applications

Home appliance control: control systems for home appliances such as washing machines, microwave ovens and air conditioners.

Industrial automation: used for control and monitoring of industrial equipment.

Internet of Things devices: smart homes, health monitoring devices and other IoT applications.

  1. CPU (Central Processing Unit)

5.1 Basic Concepts

CPU (Central Processing Unit) is the core processor of a computer, responsible for executing program instructions and processing data. CPU is called the "brain" of the computer and is the core of the entire computer system.

5.2 Features

High performance: CPU has powerful computing power and multi-threaded processing capabilities.

Multi-purpose: CPU is suitable for a wide range of applications, including general computing, graphics processing, and data processing.

Complexity: Modern CPUs have complex architectures and advanced features such as multi-level caches, branch prediction, and superscalar execution.

5.3 Applications

Personal computers: Main processors for desktops and laptops.

Servers: High-performance computing servers in data centers and cloud computing.

Workstations: High-performance workstations for graphic design, scientific computing, and engineering applications.