ARM Cortex-A

The ARM Cortex-A is a group of 32-bit RISC ARM processor cores licensed by ARM Holdings. The cores are intended for application use, and consists of the ARM Cortex-A5, ARM Cortex-A7, ARM Cortex-A8, ARM Cortex-A9, ARM Cortex-A12, ARM Cortex-A15, ARM Cortex-A17 MPCore.

Overview

Main article: ARM architecture

Announced
Year	Core
2005	Cortex-A8
2007	Cortex-A9
2009	Cortex-A5
2010	Cortex-A15
2011	Cortex-A7
2013	Cortex-A12
2014	Cortex-A17

ARM license

ARM Holdings does not manufacture nor sell 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.

Silicon customization

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 an ARM IC chip, consult the manufacturer datasheet and related documentation.

Instruction sets

The Cortex-A5 / A7 / A8 / A9 / A12 / A15 / A17 cores implement the ARMv7-A architecture.

Documentation

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.

Documentation Tree (top to bottom)

1. IC Manufacturer Marketing Slides.
2. IC Manufacturer Datasheets.
3. IC Manufacturer Reference Manuals.
4. ARM Core Reference Manuals.
5. ARM Architecture Reference Manuals.

IC Manufacturers usually have additional documents, including: evaluation board user manuals, application notes, getting started with development software, software library documents, errata, and more.

See also

• Comparison of ARMv7-A cores
• ARM architecture, List of ARM microprocessor cores
• Microcontroller, List of common microcontrollers
• Embedded system, Single-board microcontroller
• JTAG, SWD

External links

Official

• ARM Cortex-A official website
• ARM Cortex-A5
• ARM Cortex-A7
• ARM Cortex-A8
• ARM Cortex-A9
• ARM Cortex-A12
• ARM Cortex-A15
• ARM Cortex-A17

Quick Reference Cards

• Instructions: Thumb (1), ARM and Thumb-2 (2), Vector Floating-Point (3), arm.com
• Opcodes: Thumb (1, 2), ARM (3, 4), GNU Assembler Directives (5).