What Is AVR?

AVR microcontrollers are tiny computers that run programs written in assembly or C. They’re often found in devices such as air conditioners, printers, medical equipment, and more.

What Is AVR

AVRs were designed to be inexpensive, easy to use, and simple to program. Hopefully, with this guide they’ll be easy to understand too!

What Is An AVR Microcontroller?

AVR microcontrollers are single chip computers that use an 8 bit or 16-bit data bus and 1 bit address bus. They are programmed using assembler language.

They were designed by Atmel Corporation. They are widely used in many applications such as industrial automation, consumer electronics, medical devices, etc.

The AVR microcontroller is an enhanced version of the 8-bit microcontroller. It was designed to be faster than 8051 and PICAXE. It is also used in many electronic products such as computers, instruments, communication systems etc.

The AVR microcontroller uses a 32-register file stack and a single high-speed I/O scheme, which improves the execution speed of instructions, overcomes the bottleneck problem, and enhances the function.

This new instruction set is called RISC (Reduced Instruction Set Computer). It uses fewer instructions than CISC, but takes longer time to process each instruction. The AVR microcontroller uses this new instruction set.


The AVR architecture was created by two Norwegians named Alf and Vegard. They gave no definitive answers about the meaning of the word “AVR,” but most people think it means Alf and Vegard’s RISCy processor.

The AVR 8-bit architecture was introduced in 1997 by Atmel. By 2003, Atelier had shipped 500 million AAVR flash microcontrollers. The Arduino platform was developed for simple electronics projects in 2005. The ATmega8 AVR chip was used as the main controller for the Arduino board.


This microcontroller features high-quality embedded flash program memory, can be re-written and erased many times, supporting ISP and IAPP, which makes it easier to debug your products.

You can also store important information in the EEPROMs for a longer period of time. The RAM capacity is very large, allowing you to develop your software in high-level languages such as C/C++ or Java.

It has a powerful anti-jamming ability. It operates at a wide voltage range. It has a strong anti-interference ability.
The input and output characteristics are similar to those of the 8051 series.

The input and output ports of parallel I/O are similar to those of Hi/Low outputs and three-state high impedance inputs. The input and output functions of the AVR are accurate. The input and output of I/O can be flexibly used.
The AVR microcontroller has many clock dividers for various purposes.

Timing time can be adjusted by changing the prescaler. The timer counter can count bidirectionally to generate a triangle wave. Outputs can be compared to the output match register to generate a PWM signal. This PWM signal can be used to control an LED or other device.

This chip is designed to be a superfast microcontroller. It has 32 general-purpose working registers and an internal watchdog timer.

Advantages Of AVR Microcontrollers

  • They have a small size. They have a low power consumption, and they are easy to use. They have a long life cycle, are cost-effective, and are reliable and stable.
  • They support multiple programming methods and are compatible with most development tools.

Disadvantages Of AVE Microcontrollers

  • They are not suitable for all types of applications. They require special hardware to operate. They are not suitable for real-time applications.


This microcontroller is used commercially in compound applications, it requires a large program memory and also needs high speed, such as the AT90S1200/AT90S2313/AT90S8515/AT90S8535, etc.

High-grade ATMega is the most popular one, which has a good amount of memory up to 256 KB and higher built-in peripherals, and fits for moderate to difficult applications.

The application models include the ATmega8/ATmega16/ATmega32/ATmega64/ATmega128 (storage capacity is 16/32/64/256/512 KB).

ICCAVR is widely used because of its strong function, simple operation, and good technical support.

When developing an AVR microcontroller using the C programming language, you must first compile the C programming source files with ICCAVR, and then open the compiled code files with AVRStudio to test your programs.

How Does An AVR Microcontroller Work?

AVR microcontrollers are very popular because they’re easy to use, and they’re inexpensive. They have an internal ADC (analog-to-digital converter) chip, and they have a byte-oriented high speed serial interface.

They have a lot of features, including multiple fixed interrupt vector entry addresses, so they can respond to interrupts quickly. They also look like the 8051 microcontroller, but they have more functionality.

AVR microcontrollers have an automatic power-up circuit, an independent watchdog timer circuit, low voltage detection circuits, multiple reset sources (automatically up and down reset, externally reset, watchdog reset, low voltage detection circuit) and many power-saving sleep modes.

It can also set up a delay operation after running the system, improving the reliability of the system, and meanwhile, the AVR computer has many power-saving sleep modes, wide voltage operating range (from 2.7V to 5V), strong anti-noise ability, etc.

Therefore, it is widely used in the electronic industry due to its advantages.

The AVR series single chip microcontrollers include many features such as flash programming, watchdog, EEPRM, synchronous/asynchronous serial port, TWI, SPI, AID, A/D converter, Timer, Counter, etc. It fully reflects the development of modern single chip technology into the “On Chip” SoC system.

Serial ports are used to transfer information over long distances using electrical signals. They connect computers together, transmit data across networks, and send messages to other devices. The serial port is a very important part of the AVR microcontroller. It is used to communicate with other devices.

The AVR microcontroller also has a high-speed operating mode. This allows you to use this device as a high-speed transmitter or receiver.

Instruction Set

Arduino uses AVR- or Arm-based microcontrollers. PIC is the oldest of the lot. There isn’t any such thing as an “Arduino Microcontroller”.

ARM microcontrollers are more powerful than AVR microcontrollers. Both use the same instruction set but differ in terms of bus width, memory size, power consumption, and speed.

The AVR instruction set is a subset of the x86 instruction set. It was designed to be used in embedded applications.

GPIO ports

GPIO ports are used to control external hardware such as motors, relays, switches, etc. Each pin may be set as an input or an output depending on what you want to do with it.

For example, if you want to turn on a relay when a button is pressed, you’ll need to use an input pin. You can also toggle individual bits using the PINx register.

Newer ATtiny AVRs have different port control register definitions than older models. These newer devices have more configuration options available. Older ATtiny AVRs do not have these extra configuration options.


Most AVR microcontrollers do not map the EEPROM into the MCU’s memory space. This means that you need to use special pointers and instructions to access the EEPROM. The AT90SC and XMEGA families allow the EEPROM to map into the data space


AVR microcontrollers might be something complex to understand, but they’re widely used, and really useful! Hopefully this article has helped to explain a little about AVR microcontrollers!

Melanie Nilsen
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