ARM9

Source: Wikipedia, the free encyclopedia.
Not to be confused with
ARMv9
.
ARM9T
General information
Designed by
Thumb (16-bit)
ARM9E
Performance
Max.
Thumb (16-bit)
ARM9EJ
Architecture and classification
Thumb (16-bit),
Jazelle (8-bit)

ARM9 is a group of

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]

Overview

See also:
List of ARM cores

With this design generation, ARM moved from a

CPU caches
and tightly coupled memories.

There are two subfamilies, implementing different ARM architecture versions.

Differences from ARM7 cores

Key improvements over ARM7 cores, enabled by spending more transistors, include:[3]

  • Decreased heat production and lower overheating risk.
  • Clock frequency improvements. Shifting from a three-stage pipeline to a five-stage one lets the clock speed be approximately doubled, on the same silicon fabrication process.
  • Cycle count improvements. Many unmodified ARM7 binaries were measured as taking about 30% fewer cycles to execute on ARM9 cores. Key improvements include:
    • Faster loads and stores; many instructions now cost just one cycle. This is helped by both the modified Harvard architecture (reducing bus and cache contention) and the new pipeline stages.
    • Exposing pipeline interlocks, enabling compiler optimizations to reduce blockage between stages.

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

NOR flash
memory. Such hybrids are no longer pure Harvard architecture processors.

ARM license

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.

Silicon customization

Integrated device manufacturers (IDM) receive the ARM Processor

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.

Cores

Year ARM9 Cores
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

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

ARM9TDMI is a successor to the popular

ARMv4T
architecture. Cores based on it support both 32-bit ARM and 16-bit Thumb instruction sets and include:

ARM9E-S and ARM9EJ-S

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]

Chips

Nintendo DSi has a chip with an ARM9 and ARM7 core
Sitara AM1x
ARM946E-S baseband processor on a Samsung SGH-D900 phone
ARM920T
ARM922T
Samsung S3C2416XH-26
  • Micrel
    /Kendin KS8695
  • NXP
    LH7A4xx
ARM925T
ARM926EJ-S
ARM940T
ARM946E-S
ARM966E-S
ARM968E-S
  • LPC2900
Unreferenced ARM9 core

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 manufacturer has additional documents, including: evaluation board user manuals, application notes, getting started with development software, software library documents, errata, and more.

See also

See also: List of ARM Cortex-M development tools

References

  1. ^ a b ARM9 Family Webpage; ARM Holdings.
  2. ISBN 0201675196
    .
  3. ^ "Performance of the ARM9TDMI and ARM9E-S cores compared to the ARM7TDMI core", Issue 1.0, dated 9 February 2000, ARM Ltd.
  4. ^ "MPCore Sample Code". Archived from the original on 11 April 2015.
  5. ^ "Teardown Tuesday: Graphing Calculator - News". www.allaboutcircuits.com. Retrieved 2021-07-12.
  6. ^ a b Atmel Legacy ARM-Based Solutions; Atmel.
  7. ^ SAM9G ARM9 Microcontrollers; Atmel.
  8. ^ SAM9M ARM9 Microcontrollers; Microchip.
  9. ^ SAM9N/CN ARM9 Microcontrollers; Atmel.
  10. ^ SAM9R/RL ARM9 Microcontrollers; Atmel.
  11. ^ SAM9X ARM9 Microcontrollers; Atmel.
  12. ^ SAM9XE ARM9 Microcontrollers; Atmel.
  13. ^ "Hardware/Starlet". Wiibrew. Archived from the original on 16 May 2020. Retrieved 14 June 2020.
  14. ^ i.MX28 Applications Processors; NXP.
  15. ^ "LPC3100/200 Series: Arm9-based microcontrollers|NXP". www.nxp.com. Retrieved 2018-07-27.
  16. ^ "iLO 4 Cryptographic Module FIPS 140-2 Non-Proprietary Security Policy" (PDF). Hewlett Packard Enterprise. 10 February 2016.
  17. ^ "SPEAr ARM 926 Microprocessors - STMicroelectronics".
  18. ^ GBATEK - GBA/NDS Technical Info - ARM CP15 ID Codes; Martin Korth
  19. ^ STR9 ARM9 Microcontrollers; STMicroelectronics.
  20. ^ "NS9210/NS9215 32-bit NET+ARM Processor Family" (PDF). Digi International.

External links

Wikimedia Commons has media related to ARM9.
ARM9 official documents
Quick Reference Cards
  • Instructions: Thumb (1), ARM and Thumb-2 (2), Vector Floating Point (3)
  • Opcodes: Thumb (1, 2), ARM (3, 4), GNU Assembler Directives 5.
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