General information | |
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Designed by | ARM Holdings |
Architecture and classification | |
Microarchitecture | ARMv4T |
Instruction set | ARM (32-bit), Thumb (16-bit) |
Performance | |
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Max. CPU clock rate | 100 MHz to 600 MHz |
Architecture and classification | |
Microarchitecture | ARMv5TE |
Instruction set | ARM (32-bit), Thumb (16-bit) |
Architecture and classification | |
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Microarchitecture | ARMv5TEJ |
Instruction set | ARM (32-bit), Thumb (16-bit), Jazelle (8-bit) |
ARM9 is a group of 32-bit RISC ARM processor cores licensed by ARM Holdings for microcontroller use. [1] The ARM9 core family consists of ARM9TDMI, ARM940T, ARM9E-S, ARM966E-S, ARM920T, ARM922T, ARM946E-S, ARM9EJ-S, ARM926EJ-S, ARM968E-S, ARM996HS. Since ARM9 cores were released from 1998 to 2006, they are no longer recommended for new IC designs, instead ARM Cortex-A, ARM Cortex-M, ARM Cortex-R cores are preferred. [1]
With this design generation, ARM moved from a von Neumann architecture (Princeton architecture) to a (modified; meaning split cache) Harvard architecture with separate instruction and data buses (and caches), significantly increasing its potential speed. [2] Most silicon chips integrating these cores will package them as modified Harvard architecture chips, combining the two address buses on the other side of separated CPU caches and tightly coupled memories.
There are two subfamilies, implementing different ARM architecture versions.
Key improvements over ARM7 cores, enabled by spending more transistors, include: [3]
Additionally, some ARM9 cores incorporate "Enhanced DSP" instructions, such as a multiply-accumulate, to support more efficient implementations of digital signal processing algorithms.
Switching from a von Neumann architecture entailed using a non-unified cache, so that instruction fetches do not evict data (and vice versa). ARM9 cores have separate data and address bus signals, which chip designers use in various ways. In most cases they connect at least part of the address space in von Neumann style, used for both instructions and data, usually to an AHB interconnect connecting to a DRAM interface and an External Bus Interface usable with NOR flash memory. Such hybrids are no longer pure Harvard architecture processors.
ARM Holdings neither manufactures nor sells CPU devices based on its own designs, but rather licenses the processor architecture to interested parties. ARM offers a variety of licensing terms, varying in cost and deliverables. To all licensees, ARM provides an integratable hardware description of the ARM core, as well as complete software development toolset and the right to sell manufactured silicon containing the ARM CPU.
Integrated device manufacturers (IDM) receive the ARM Processor IP as synthesizable RTL (written in Verilog). In this form, they have the ability to perform architectural level optimizations and extensions. This allows the manufacturer to achieve custom design goals, such as higher clock speed, very low power consumption, instruction set extensions, optimizations for size, debug support, etc. To determine which components have been included in a particular ARM CPU chip, consult the manufacturer datasheet and related documentation.
Year | ARM9 Cores |
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1998 | ARM9TDMI |
1998 | ARM940T |
1999 | ARM9E-S |
1999 | ARM966E-S |
2000 | ARM920T |
2000 | ARM922T |
2000 | ARM946E-S |
2001 | ARM9EJ-S |
2001 | ARM926EJ-S |
2004 | ARM968E-S |
2006 | ARM996HS |
The ARM MPCore family of multicore processors support software written using either the asymmetric (AMP) or symmetric (SMP) multiprocessor programming paradigms. For AMP development, each central processing unit within the MPCore may be viewed as an independent processor and as such can follow traditional single processor development strategies. [4]
ARM9TDMI is a successor to the popular ARM7TDMI core, and is also based on the ARMv4T architecture. Cores based on it support both 32-bit ARM and 16-bit Thumb instruction sets and include:
ARM9E, and its ARM9EJ sibling, implement the basic ARM9TDMI pipeline, but add support for the ARMv5TE architecture, which includes some DSP-esque instruction set extensions. In addition, the multiplier unit width has been doubled, halving the time required for most multiplication operations. They support 32-bit, 16-bit, and sometimes 8-bit instruction sets.
The TI-Nspire CX (2011) and CX II (2019) graphing calculators use an ARM926EJ-S processor, clocked at 132 and 396 MHz respectively. [5]
The amount of documentation for all ARM chips is daunting, especially for newcomers. The documentation for microcontrollers from past decades would easily be inclusive in a single document, but as chips have evolved so has the documentation grown. The total documentation is especially hard to grasp for all ARM chips since it consists of documents from the IC manufacturer and documents from CPU core vendor (ARM Holdings).
A typical top-down documentation tree is: high-level marketing slides, datasheet for the exact physical chip, a detailed reference manual that describes common peripherals and other aspects of physical chips within the same series, reference manual for the exact ARM core processor within the chip, reference manual for the ARM architecture of the core which includes detailed description of all instruction sets.
IC manufacturer has additional documents, including: evaluation board user manuals, application notes, getting started with development software, software library documents, errata, and more.
A microcontroller or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs along with memory and programmable input/output peripherals. Program memory in the form of NOR flash, OTP ROM, or ferroelectric RAM is also often included on the chip, as well as a small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general-purpose applications consisting of various discrete chips.
ARM is a family of RISC instruction set architectures (ISAs) for computer processors. Arm Ltd. develops the ISAs and licenses them to other companies, who build the physical devices that use the instruction set. It also designs and licenses cores that implement these ISAs.
SuperH is a 32-bit reduced instruction set computing (RISC) instruction set architecture (ISA) developed by Hitachi and currently produced by Renesas. It is implemented by microcontrollers and microprocessors for embedded systems.
JTAG is an industry standard for verifying designs of and testing printed circuit boards after manufacture.
ARM7 is a group of 32-bit RISC ARM processor cores licensed by ARM Holdings for microcontroller use. The ARM7 core family consists of ARM700, ARM710, ARM7DI, ARM710a, ARM720T, ARM740T, ARM710T, ARM7TDMI, ARM7TDMI-S, ARM7EJ-S. The ARM7TDMI and ARM7TDMI-S were the most popular cores of the family.
Atmel ARM-based processors are microcontrollers and microprocessors integrated circuits, by Microchip Technology, that are based on various 32-bit ARM processor cores, with in-house designed peripherals and tool support.
AVR32 is a 32-bit RISC microcontroller architecture produced by Atmel. The microcontroller architecture was designed by a handful of people educated at the Norwegian University of Science and Technology, including lead designer Øyvind Strøm and CPU architect Erik Renno in Atmel's Norwegian design center.
PSoC is a family of microcontroller integrated circuits by Cypress Semiconductor. These chips include a CPU core and mixed-signal arrays of configurable integrated analog and digital peripherals.
ARM11 is a group of 32-bit RISC ARM processor cores licensed by ARM Holdings. The ARM11 core family consists of ARM1136J(F)-S, ARM1156T2(F)-S, ARM1176JZ(F)-S, and ARM11MPCore. Since ARM11 cores were released from 2002 to 2005, they are no longer recommended for new IC designs, instead ARM Cortex-A and ARM Cortex-R cores are preferred.
Nomadik is a family of microprocessors for multimedia applications from STMicroelectronics, and later ST-NXP Wireless. It was originally based on the ARM9 ARM architecture(s), and was designed specifically for use in mobile devices.
The i.MX range is a family of Freescale Semiconductor proprietary microcontrollers for multimedia applications based on the ARM architecture and focused on low-power consumption. The i.MX application processors are SoCs (System-on-Chip) that integrate many processing units into one die, like the main CPU, a video processing unit, and a graphics processing unit for instance. The i.MX products are qualified for automotive, industrial, and consumer markets. Most of them are guaranteed for a production lifetime of 10 to 15 years.
Devices that use i.MX processors include Ford Sync, the Amazon Kindle and Kobo eReader series of e-readers until 2021, Zune, Sony Reader, Onyx Boox readers/tablets, SolidRun SOM's, Purism's Librem 5, some Logitech Harmony remote controls and Squeezebox radio and some Toshiba Gigabeat MP4 players. The i.MX range was previously known as the "DragonBall MX" family, the fifth generation of DragonBall microcontrollers. i.MX originally stood for "innovative Multimedia eXtension".
The ARM Cortex-M is a group of 32-bit RISC ARM processor cores licensed by ARM Limited. These cores are optimized for low-cost and energy-efficient integrated circuits, which have been embedded in tens of billions of consumer devices. Though they are most often the main component of microcontroller chips, sometimes they are embedded inside other types of chips too. The Cortex-M family consists of Cortex-M0, Cortex-M0+, Cortex-M1, Cortex-M3, Cortex-M4, Cortex-M7, Cortex-M23, Cortex-M33, Cortex-M35P, Cortex-M52, Cortex-M55, Cortex-M85. A floating-point unit (FPU) option is available for Cortex-M4 / M7 / M33 / M35P / M52 / M55 / M85 cores, and when included in the silicon these cores are sometimes known as "Cortex-MxF", where 'x' is the core variant.
The ARM Cortex-A is a group of 32-bit and 64-bit RISC ARM processor cores licensed by Arm Holdings. The cores are intended for application use. The group consists of 32-bit only cores: ARM Cortex-A5, ARM Cortex-A7, ARM Cortex-A8, ARM Cortex-A9, ARM Cortex-A12, ARM Cortex-A15, ARM Cortex-A17 MPCore, and ARM Cortex-A32, 32/64-bit mixed operation cores: ARM Cortex-A35, ARM Cortex-A53, ARM Cortex-A55, ARM Cortex-A57, ARM Cortex-A72, ARM Cortex-A73, ARM Cortex-A75, ARM Cortex-A76, ARM Cortex-A77, ARM Cortex-A78, ARM Cortex-A710, and ARM Cortex-A510 Refresh, and 64-bit only cores: ARM Cortex-A34, ARM Cortex-A65, ARM Cortex-A510 (2021), ARM Cortex-A715, ARM Cortex-A520, and ARM Cortex-A720.
STM32 is a family of 32-bit microcontroller integrated circuits by STMicroelectronics. The STM32 chips are grouped into related series that are based around the same 32-bit ARM processor core: Cortex-M0, Cortex-M0+, Cortex-M3, Cortex-M4, Cortex-M7, Cortex-M33. Internally, each microcontroller consists of ARM processor core(s), flash memory, static RAM, debugging interface, and various peripherals.
The ARM Cortex-A5 is a 32-bit processor core licensed by ARM Holdings implementing the ARMv7-A architecture announced in 2009.
SmartFusion is a family of microcontrollers with an integrated FPGA of Actel. The device includes an ARM Cortex-M3 hard processor core and analog peripherals such as a multi-channel ADC and DACs in addition to their flash-based FPGA fabric.
XMC is a family of microcontroller ICs by Infineon. The XMC microcontrollers use the 32-bit RISC ARM processor cores from ARM Holdings, such as Cortex-M4F and Cortex-M0. XMC stands for "cross-market microcontrollers", meaning that this family can cover due to compatibility and configuration options, a wide range in industrial applications. The family supports three essential trends in the industry: It increases the energy efficiency of the systems, supports a variety of communication standards and reduces software complexity in the development of the application's software environment with the parallel released eclipse-based software tool DAVE.
LPC is a family of 32-bit microcontroller integrated circuits by NXP Semiconductors. The LPC chips are grouped into related series that are based around the same 32-bit ARM processor core, such as the Cortex-M4F, Cortex-M3, Cortex-M0+, or Cortex-M0. Internally, each microcontroller consists of the processor core, static RAM memory, flash memory, debugging interface, and various peripherals. The earliest LPC series were based on the Intel 8-bit 80C51 core. As of February 2011, NXP had shipped over one billion ARM processor-based chips.
In computing, autonomous peripheral operation is a hardware feature found in some microcontroller architectures to off-load certain tasks into embedded autonomous peripherals in order to minimize latencies and improve throughput in hard real-time applications as well as to save energy in ultra-low-power designs.