ARM architecture: history and curiosities of microprocessors

Billions and billions of ARM systems, paraphrasing the title of a book by Carl Sagan who, in addition to being one of the greatest and most famous astrophysicists of the last century, was also a professor of astronomy at Cornell University, founded the Planetary Society and the Seti project. Once upon a time to specify a large quantity we spoke of millions today instead to refer to large multitudes we must speak of billions. Billions of billions, but of what? Of electronic devices. What can billions of electronic devices have in common today in the 21st century?

Architecture and organization

What can be the least common denominator of billions of systems and many devices? What can all or almost all devices, portable or otherwise, produced by the modern electronics industries have in common? Most likely the answer lies in the model of their architecture and organization.

At the heart of this architecture is the ARM chip which is the "beating" heart, the "thinking" brain, of a family of processors. With the term " computer architecture " we mean the different design choices to create a hardware system . By organization, on the other hand, we refer to the structural relationships between the functional units of the computer and the way in which they build a given architecture.

ARM architecture

So, like all microprocessors, even those of the ARM family, they control, among other things, the use and flow of data. Data and processes are processed as a continuous flow of 1s and 0s. The order of these 1s and 0s takes on meaning for the microprocessor, and a particular sequence of them will be translated into a series of actions. A nice analogy can be found in Morse code, where a series of dots and lines sent in the correct order take on a certain meaning.


To highlight the power of the ARM chip and consequently also of the most popular devices that are equipped with it that almost all of us use every day, it is worth remembering the existence of a generation of satellites called CubeSats, characterized by very small dimensions, specific and equipped tasks. with ARM µprocessors . This article was created with the aim of deepening the knowledge of a particular digital computer architecture. To get closer to the emerging and most widespread technologies in the domain of modern device architectures.

The state of the art in the technological sector places a certain knowledge of ARM architecture as a sine qua non .

The history of ARM architecture

The acronym ARM is used for the first time in 1983 : conceived by Acorn Computers and refers to a family of processors based on RISC principles. In the early nineties, ARM becomes a real company, ie ARM ltd: Where ARM stands for Advanced RISC Machine . In the following years a collaboration agreement is made between Acorn Computers, Apple, and VLSI Technology. The primary purpose of the agreement is to advance in the development of RISC processors, used by Acorn and chosen by Apple for its platform.

Over the years, many people and companies have contributed to the success of this family of ARM system chips . It is not possible to name them all but as history sometimes has a habit of focusing credit on one or more high-profile people, often at the expense of those who work head-on to get the job done on time, we cannot don't mention when talking about ARM, Sophie Wilson.

Wilson at the time a young rising star of the British computer industry conceived and designed one of the first ARM microprocessors and systems along with its instruction set. The original architecture together with the instruction set survive, extensive, but otherwise largely the same, to this day. Wilson also made a computer prototype that became the starting point for building the first Acorn System computer.

The origins of ARM architecture

Smartphones, laptops, consoles, tablets and ARM systems enjoy its intrinsic characteristics. Among these features stand out: computing power, and energy efficiency. As for the software, we also find differences in the versions of the CPU. The ARM chip has undergone continuous development over time but also had problems. Despite the developments, the basic instruction set remains the same even if more extensive, which is why porting is not that difficult. On the other hand, things get complicated only if you use more advanced microprocessor features.

ARM systems
Raspberry pi is a small computer developed on a single board.

The raspberry pi is a small computer developed in the UK by the Raspberry Pi Foundation . Since its first version and subsequent revisions it uses an ARM Cortex processor.

The article ARM Architecture: history and curiosities of microprocessors was written on: Tech CuE | Close-up Engineering .