Massmind : CPUs : Atmel : AVR

RISC core running single cycle instructions. 32 general purpose registers. On chip hardware includes: Internal oscillators, timers, UART, SPI, USB, pull-up resistors, pulse width modulation, ADC, analog comparator, up to 4x40 LCD drivers and watch-dog timers. On chip in-system programmable Flash and EEPROM. 1.8-5.5 Volt power options. Software controlled frequency and sleep modes with fast wakeup. Used in popular Arduino system.


The Atmel AVR and the Microchip PIC are very similar (Harvard architecture) lines of microcontrollers.

Advantages of Atmel AVR:

Disadvantages of Atmel AVR:

Common misperceptions: Some people think the fastest Microchip PIC (20 MHz 4:1 pipeline) is as fast as the fastest Atmel AVR (20 MHz 1:1 pipeline). They are wrong. The PIC is actually processing instructions at 5 MIPS and the AVR is at just under 20 MIPS. Also, the AVR instruction set is larger, so in many cases, it is getting more done in fewer cycles.

In System Development: The device is its own emulator which ensures actual behavior and electrical characteristics. You will have all resources available while debugging, and it is available on the tiniest 8-pin parts to the large 100-pin devices. AVR devices also support self-programming, allowing them to upgrade their own firmware. A single, free tool chain supports the entire AVR line. Assembler, Simulator, ICE, C and C++ support included at no cost. FORTH, Pascal, BASIC and many flavors of C and C++ are available from 3rd party vendors.

Groups: The AVR line is divided into to major groups; Tiny and Mega, with some additional special function versions for specific applications such as lighting, automotive, battery management, rf comms, and LCD drivers.

Development Tools

Code Library


A small robot board with the AVR by Dimitar Dimitrov

ATMEL AVR USB Programmer and Rapid Prototyping Board by Tobias Frost

Free IDE

See also:

Distributed by:

Ingmar Meins AVR software video and other routines.



AVR Timers