The AVR is a modified Harvard architecture

Modified Harvard architecture

The Modified Harvard Architecture is a variation of the Harvard computer architecture that allows the contents of the instruction memory to be accessed as if it were data...

 8-bit

8-bit

The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...

 RISC

Reduced instruction set computer

Reduced instruction set computing, or RISC , is a CPU design strategy based on the insight that simplified instructions can provide higher performance if this simplicity enables much faster execution of each instruction. A computer based on this strategy is a reduced instruction set computer...

 single chip microcontroller

Microcontroller

A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...

 which was developed by Atmel

Atmel

Atmel Corporation is a manufacturer of semiconductors, founded in 1984. Its focus is on system-level solutions built around flash microcontrollers...

 in 1996. The AVR was one of the first microcontroller families to use on-chip flash memory

Flash memory

Flash memory is a non-volatile computer storage chip that can be electrically erased and reprogrammed. It was developed from EEPROM and must be erased in fairly large blocks before these can be rewritten with new data...

 for program storage, as opposed to one-time programmable ROM

Programmable read-only memory

A programmable read-only memory or field programmable read-only memory or one-time programmable non-volatile memory is a form of digital memory where the setting of each bit is locked by a fuse or antifuse. Such PROMs are used to store programs permanently...

, EPROM

EPROM

An EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...

, or EEPROM

EEPROM

EEPROM stands for Electrically Erasable Programmable Read-Only Memory and is a type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed, e.g., calibration...

 used by other microcontrollers at the time.
The AVR architecture was conceived by two students at the Norwegian Institute of Technology

Norwegian Institute of Technology

The Norwegian Institute of Technology, known by its Norwegian abbrevation NTH was a science institute in Trondheim, Norway. It was established in 1910, and existed as an independent technical university for 85 years, after which it was merged into the University of Trondheim as an independent...

 (NTH) Alf-Egil Bogen and Vegard Wollan.

The original AVR MCU was developed at a local ASIC

Application-specific integrated circuit

An application-specific integrated circuit is an integrated circuit customized for a particular use, rather than intended for general-purpose use. For example, a chip designed solely to run a cell phone is an ASIC...

 house in Trondheim, Norway called Nordic VLSI at the time, now Nordic Semiconductor, where the two founders of Atmel Norway were working as students.