General properties of AVR microcontrollers

Ability to work at 1MIPS/MHz (MIPS – Millions Instructions Per Second);

On chip Flash memory (now tiny series have up to 8kB, mega up to 256kB) with write cycle not less than 1000 times;

On chip RAM memory (tiny series up to 512B, mega up to 8kB);

On chip EEPROM memory (tiny series up to 512B, mega up to 4kB) with write cycle not less than 100000 times;

Working frequencies up to 20MHz;

Protection fuses from unintentional reading and modification of program and data memories;

Ability to program in system – directly on board using ISP cable;

Four types of clock generators: Internal generator, RC generator of clock cycles, Internal generator with external crystal resonator, and External synchronisation;

Two or three power down modes;

Some microcontroller can work at very low voltages like 1.8V;

Static architecture where minimal frequency equal to zero;

ALU is connected directly to general purpose registers;

Most of commands are performed in one clock cycle;

Multilevel system of interrupts;

Many sources of interrupts – two of them are external;

Three level hardware stack.

Software configurable and selection of I/O ports;

Ports can be programmed as inputs and outputs independently to each other;

Input buffers uses Smith triggers on all pins;

Support of Internal Pull-Up resistors (about 35 to 120kOhm);

8 bit timer counter with pre-scaler;

16 bit timer counter with pre-scaler ;

Watch dog timer;

PWM generator;

Analog comparator;

ADC;

Hardware modulator;

SPI interface;

TWI (I2C) interface;

UART;