ARM Microcontroller History

In 1983, a company named ACORN was searching for a 16 bit microprocessor for their desktop machine. They were not satisfied with the existing processor in the market as the processor had slower memory accessing. The processor had complex instruction which took hundreds of cycle to execute, which also rose to high interrupt latency. At that time minicomputer consisted of many chips and controlled by microcode with complex instruction. The UP in market could not match Acorn’s demand so Acorn engineers took initiative to design their own UP. In the mean time Berkeley RISC 1 project showed that there can be simple architecture of UP with performance equivalent to CISC.

Acorn took the Berkeley approach and 2 yr later, in 1985. They released the first 26-bitRISC processor. This 26-bit RISC processor had performance as though of Intel 80826 processor. In 1987, Acorn introduced ARM v2 with coprocessor support. Later in the same year it introduced ARM 3 which included on-chip cache on processor.

In 1990, APPLE decided to use ARM processor in the NEWTON PAD. The collaboration of Acorn and APPLE designed a new processor. The company Acorn renamed to ARM (Advanced RISC Machine) processor. The ARM v3 architecture was featured with 32-bit addressing, MMU, 64bit-MAI (multiply accumulate instruction). ARM v3 architecture was implemented on ARM6 & ARM& core. The APPLE product NEWTON PAD launched in 1992 and ARM stepped to embedded market.

In 1996, 4th generation ARM was introduced. It was featured with THUMB instruction set. Thumb instruction set reduced the code density of RISC processor. ARM7TDMI was the most prominent ARM v4 product. In 1999, ARM 5th generation architecture introduced with DSP (Digital signal processing) and JAVA byte code extension to the ARM instruction set. The most popular implementation of this architecture is the Intel X scale processor. It is used in a variety of Embedded device, including network processing. The 6th generation of ARM architecture was released in 2001. It was featured with SIMD instruction set, improved THUMB instruction set, trust zone virtualization technology and multiprocessor. ARM 11 & ARM 11 MP core are the product of ARMv4.