Atmel says that the name AVR is not an acronym and does not stand for anything in particular. The creators of the AVR give no definitive answer as to what the term "AVR" stands for.<ref name="storyofavr" /> However, it is commonly accepted that AVR stands for '''A'''lf and '''V'''egard's '''R'''ISC processor.<ref>{{cite web|title=UNSW School of Computer Science and Engineering - General AVR Info|url=http://www.cse.unsw.edu.au/~pcb/avr/avr.html|url-status=dead|archive-url=https://web.archive.org/web/20120623131604/http://www.cse.unsw.edu.au/~pcb/avr/avr.html|archive-date=2012-06-23|access-date=2012-09-19|publisher=Cse.unsw.edu.au}}</ref> Note that the use of "AVR" in this article generally refers to the 8-bit RISC line of Atmel AVR microcontrollers.
The original AVR MCU was developed at a local [[Application-specific integrated circuit|ASIC]] house{{Clarify|reason=Meaningdesign of the phrase is unclear.|date=January 2023}}company in [[Trondheim, Norway]], called Nordic VLSI at the time, now [[Nordic Semiconductor]], where Bogen and Wollan were working as students.{{Citation needed|date=December 2010}} It was known as a μRISC (Micro RISC)<ref name="NTNU">[https://www.itk.ntnu.no/fag/TTK4155/2004/foiler_forelesninger/Atmel_AVR_Forelesning.pdf An introduction to Atmel and the AVR microcontroller]{{Dead link|date=February 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> and was available as silicon IP/building block from Nordic VLSI.<ref>{{Cite web |url=http://www.idi.ntnu.no/~dam/fag/digdat/DigDat301002.pdf |title=Embedded Systems and Microcontrollers |access-date=2018-10-01 |archive-url=https://web.archive.org/web/20041224014455/http://www.idi.ntnu.no/~dam/fag/digdat/DigDat301002.pdf |archive-date=2004-12-24 |url-status=dead }}</ref> When the technology was sold to Atmel from Nordic [[Very-large-scale integration|VLSI]], the internal architecture was further developed by Bogen and Wollan at Atmel Norway, a subsidiary of Atmel. The designers worked closely with compiler writers at [[IAR Systems]] to ensure that the AVR instruction set provided efficient [[Compiler|compilation]] of [[High-level programming language|high-level languages]].<ref name="codesign">{{cite book|url=http://www.atmel.com/dyn/resources/prod_documents/COMPILER.pdf|title=The AVR Microcontroller and C Compiler Co-Design|last=Myklebust|first=Gaute|publisher=Atmel Norway|citeseerx=10.1.1.63.1447|access-date=2012-09-19}}</ref>
Among the first of the AVR line was the AT90S8515, which in a 40-pin DIP package has the same pinout as an [[Intel 8051|8051]] microcontroller, including the external multiplexed address and data bus. The polarity of the <span style="text-decoration: overline">RESET</span> line was opposite (8051's having an active-high RESET, while the AVR has an active-low <span style="text-decoration: overline">RESET</span>), but other than that the pinout was identical.
