History and Classification of ARM Processors

In December 1978, physicist Hermann Hauser and engineer Chris Curry founded the Cambridge Processing Unit (CPU) in Cambridge, UK, initially supplying electronic equipment to the local market. The company was renamed Acorn Computers in 1979.

In 1985, Roger Wilson and Steve Furber designed a 32‑bit, 6 MHz processor and built a RISC‑based computer called ARM (Acorn RISC Machine), producing the first ARM1 processor followed by the improved ARM2, which was used in the BBC Archimedes 305.

Acorn was later acquired by Olivetti, and on 27 November 1990 ARM Ltd. was spun out as an independent processor company, funded by Apple (£1.5 M), VLSI (£0.25 M) and Acorn’s IP and engineers (£1.5 M). The early office was a simple barn.

The project progressed to ARM6, with the first samples released in 1991; Apple used the ARM610 in its Newton devices, and in 1994 Acorn computers employed the ARM610 in personal computers.

Product Classification

ARM products are classified by architecture generations (ARMv1, ARMv2, ARMv3, …) and corresponding cores such as ARM1, ARM2, ARM6, ARM7, ARM9, ARM10, ARM11 and the Cortex series. Later generations have higher clock rates, more advanced features, and greater functionality.

Below is a diagram (from Wikipedia) showing the relationship between architectures and cores.

https://en.wikipedia.org/wiki/List_of_ARM_microarchitectures

ARM also designs its own cores (see image).

Another image shows the release timeline of ARM cores.

Besides ARM’s own designs, other companies with an ARM architecture licence have implemented their own ARM‑compatible cores (see image).

In summary, ARM processors are divided into the classic ARM series and the newer Cortex series.

Classic Processors

ARM7 family : Launched in 1994, the most widely used 32‑bit embedded processor series, featuring a 0.9 MIPS/MHz three‑stage pipeline and Von Neumann architecture. Variants include ARM7TDMI, ARM7TDMI‑S and ARM720T, offering Thumb 16‑bit compression and EmbeddedICE debugging.

ARM9 family : Uses a Harvard architecture with separate instruction and data buses, a five‑stage pipeline (versus ARM7’s three‑stage), delivering higher performance and low‑power operation for embedded products, capable of running Linux, Windows CE, and supporting audio, industrial, and mobile applications.

ARM9E family : Enhances ARM9 with DSP‑type instructions (E = Enhanced), providing a single‑core solution for microcontroller, DSP, and Java applications, reducing chip area and system complexity.

ARM10E family : Similar to ARM9E but employs a Harvard architecture, six‑stage pipeline, and up to 325 MHz clock (≈1.35 MIPS/MHz).

ARM11 family : Implements the ARMv6 architecture with cores ARM1136J, ARM1156T2 and ARM1176JZ, targeting wireless, consumer electronics, networking, and automotive applications with strong media processing and low power consumption.

Cortex series

After the classic ARM11, ARM renamed its products as Cortex, divided into three groups: Cortex‑A (applications), Cortex‑R (real‑time), and Cortex‑M (microcontrollers), each built on the ARMv7 architecture and optimized for different market segments.

Application Processors : High‑end processors for mobile, smartphones, servers, etc., running at >1 GHz, supporting full MMU and operating systems such as Linux, Android, and Windows.

Real‑time Processors : Designed for high‑performance real‑time applications (e.g., storage controllers, automotive, baseband), typically lacking an MMU but offering MPU, cache, and low‑latency operation.

Microcontroller Processors : Small‑area, high‑efficiency cores with short pipelines and lower clock rates (some up to 200 MHz), exemplified by the Cortex‑M family (e.g., Cortex‑M4, Cortex‑M7) used in many high‑performance microcontroller products.

Author: CSDN blogger ZCShouEXP

Original link: https://blog.csdn.net/ZCShouCSDN/article/details/84393473

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