What is an AVR ???
Well ! What AVR stands for ??? aah, nothing its just a 3 letter word, like PIC. Some people name it “Advanced Virtual RISC”.
You may not like any kind of heavy definition to begin with. Ok ! AVR is a Micro-controller architecture by a company called Atmel, and this AVR thing is very popular among electronics hobbyists and makers around the globe.
They are RISC devices. RISC stands for “reduced instruction set computing” and means that the devices are designed to run very fast through the use of a reduced numbers of machine level instructions.
This reduced number of instructions contributes tp the speeddue to the fact that, with a limited numbers of machine instructions, most can run in a single cycle of processor clock.
All of the above statements means to say that an AVR processor using an 8MHz clock can execute nearly 8 million instructions per second, that is a speed of nearly 8 MIPS.
As said earlier AVR is first of all a micro-controller. So it has internal Memory, I/O ports and many other peripherals.
The memory section of the Atmel RISC avr processor is based on the harvard modal, in which various portions of the memory are seperated to allow faster access and increased capacity. The CPU has a seperate interface for the FLASH code memory section, the data memory section, and the EEPROM section, if one is present.
AVR is very rich in On chip peripherals. They have almost all the features required in a modern days micro-controller.
To learn more about Rich features of AVR read some initial pages from Datasheet of ATMega16.
Misconception There is a common misconception that ATmega8 is 8 bit, ATmega16 is 16 bit and ATmega32 is 32 bit CPU. NOT at ALL! They are all 8 bit CPU’s, this naming convention is due to the increasing set of features and Memory these device consists of, it has nothing to do with CPU, all of them equipped with same CPU’s.