Difference between 8051 and ARM

A microcontroller is a small processing device which is primarily designed to perform specific functions within a large system. For example, a microcontroller is used in an air conditioner to automatically control and adjust the temperature of a room.

The main parts that a microcontroller has are: central processing unit (CPU), memory unit, and I/O interfaces. All these components of the microcontroller are formed on a single chip. A microcontroller can be programmed using various programming languages like C language, assembly language, etc. to perform a specific function. Microcontrollers are widely used in a variety of electronic devices, such as medical instruments, manufacturing machinery, robotics, automobiles, home appliances, toys, etc. to automate their operation.

Based on the architecture, there are several different types of microcontrollers are available. The 8085 and ARM are the two different microcontroller architectures. The fundamental difference between them is in their processor architecture, i.e. the 8051 microcontroller is an 8-bit microcontroller, while the ARM (Advanced RISC Machine) is a 32-bit microcontroller.

In this article, we will discuss all the important differences between 8051 and ARM microcontrollers. But before that let us first have a look into their basics.

What is an 8051 Microcontroller?

8051 microcontroller is an 8-bit microcontroller developed by Intel in 1980. 8051 microcontroller is an entry level popular microcontroller used in many embedded systems and automation applications.

The 8051 microcontroller supports many advanced features, such as interrupts, serial communication, and timers. The 8051 microcontroller uses Von Neumann Memory architecture.

The 8051 microcontroller has an 8-bit microprocessor, a number of built-in peripherals, and on-chip RAM and ROM. Although, the memory space in the 8051 microcontrollers can be extended with an external memory device as needed.

The 8051 microcontroller uses a simple instruction set. Therefore, it can be easily programmed using either low-level assembly language or high-level languages like C.

The major advantages of the 8051 microcontrollers include simpler design, versatility, low power consumption, low cost, etc. Therefore, the 8051 microcontroller is commonly used in embedded systems, energy management systems, automobiles, medical instruments, etc.

What is an ARM Microcontroller?

ARM is the abbreviation for Advanced RISC Machine. ARM microcontroller is a 32-bit architecture microcontroller that was developed by Acorn Computers in 1983.

ARM is basically a family of Reduced Instruction Set Computing (RISC) architecture-based microprocessors. ARM microcontrollers consist of ARM processors, RAM, ROM, and I/O peripherals. ARM microcontrollers are used in a wide range of applications due to their low power consumption, low cost, and high performance.

One of the important features of ARM microcontrollers is that they are highly customizable depending on requirements of the applications. Therefore, it is highly versatile microcontroller architecture.

We can use assembly language as well as high level programming languages such as C, C++ to program the ARM microcontrollers. ARM microcontrollers are highly scalable; hence they can be used in several applications, from simple embedded systems to high-end computing systems.

After getting insights into the basics of 8051 and ARM, let us now discus the important differences between them.

Difference between 8051 and ARM

The following table gives all the major differences between 8051 and ARM microcontrollers −


8051 Microcontroller

ARM Microcontroller


8051 is a simple and low cost 8-bit microcontroller used in several types of embedded system applications.

ARM (Advanced RISC Machine) is low cost and high performance 32-bit microcontroller architecture used in a variety of applications, from simple embedded systems to high-end computing systems.

Bus width

8051 microcontrollers have a bus width of 8-bits.

ARM microcontrollers have a bus width of 32-bits. Some modern ARM microcontrollers are also available in 64-bit bus width.


8051 was developed by Intel.

ARM was developed by Acorn Computers.

Release date

8051 was first released in the year 1980.

ARM was first released in 1983.

Power consumption

For 8051 microcontrollers, the power consumption is average.

ARM microcontrollers consume relatively less power than 8051 microcontrollers.


8051 microcontrollers are less expensive.

ARM microcontrollers are comparatively more expensive than 8051.

Built-in peripherals

8051 microcontrollers have a smaller number of built-in peripherals.

ARM microcontrollers have a greater number of built-in peripherals than 8051.


8051 microcontrollers have average performance.

ARM microcontrollers have high performance.


8051 microcontrollers are better suited for simple embedded systems.

The more powerful architecture of ARM microcontrollers makes them suitable for a wide range of applications, from simple embedded systems to high-performance computing systems.

Instruction set

8051 microcontrollers have simple instruction sets.

ARM microcontrollers have complex instruction sets than 8051.


8051 microcontrollers have a slower clock speed; thus, they can process lesser number of instructions per second.

ARM microcontrollers have faster clock speed, allowing them to process more instructions per second.

Memory architecture

8051 microcontrollers use Von Neumann Architecture.

ARM microcontrollers use Modified Harvard Architecture.

Instruction set architecture

8051 microcontrollers have CISC (Complex Instruction Set Computer) architecture.

ARM microcontrollers have RISC (Reduced Instruction Set Computer) architecture.

Communication protocols

The communication protocols used in 8051 microcontrollers are UART, SPI, USART, and I2C.

The communication protocols used in ARM microcontrollers are UART, USART, SPI, I2C, I2S, LIN, CAN, DSP, SAI, and IrDA.

Popular microcontrollers

Some popular microcontrollers of 8051 family are P89v51, AT89C51, etc.

Some popular microcontrollers of ARM family are ARM Cortex-M0 to M7, LPC2148, etc.


Both 8051 and ARM microcontrollers are widely used in several applications, such as embedded systems, automobiles, medical instruments, etc. The most significant difference between 8051 and ARM is that the 8051 microcontroller has an 8-bit architecture, whereas the ARM microcontroller has a 32-bit architecture.

Updated on: 21-Apr-2023

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