View source for ARM9

{{Short description|Family of microprocessor cores with ARM microarchitecture}}
{{distinguish|ARMv9}}
{{Infobox CPU
|name       = ARM9T
|designfirm = [[ARM Holdings]]
|arch       = [[ARM architecture#32-bit architecture|ARM (32-bit)]],<br />[[ARM architecture#Thumb|Thumb (16-bit)]]
|microarch  = ARMv4T
}}
{{Infobox CPU
|name       = ARM9E
|arch       = [[ARM architecture#32-bit architecture|ARM (32-bit)]],<br />[[ARM architecture#Thumb|Thumb (16-bit)]]
|microarch  = ARMv5TE
|fastest=600
|slowest=100
|slow-unit=MHz
|fast-unit=MHz
}}
{{Infobox CPU
|name       = ARM9EJ
|arch       = [[ARM architecture#32-bit architecture|ARM (32-bit)]],<br />[[ARM architecture#Thumb|Thumb (16-bit)]],<br />[[Jazelle|Jazelle (8-bit)]]
|microarch  = ARMv5TEJ
}}

'''ARM9''' is a group of [[32-bit]] [[reduced instruction set computer|RISC]] [[ARM architecture|ARM]] processor cores licensed by [[ARM Holdings]] for [[microcontroller]] use.<ref name="ARM9-Web">[https://www.arm.com/products/processors/classic/arm9/index.php ARM9 Family Webpage; ARM Holdings.]</ref>  The ARM9 core family consists of ARM9TDMI, ARM940T, ARM9E-S, ARM966E-S, ARM920T, ARM922T, ARM946E-S, ARM9EJ-S, ARM926EJ-S, ARM968E-S, ARM996HS.  ARM9 cores were released from '''1998''' to '''2006''', and no longer recommended for new IC designs; newer alternatives are [[ARM Cortex-M]] cores.<ref>[https://oemdrivers.com/arm9 ARM9; OEMDrivers.]</ref>

==Overview==
{{See also|ARM architecture|List of ARM cores}}

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 [[bus (computing)|data buses]] (and caches), significantly increasing its potential speed.<ref>{{cite book|last1=Furber|first1=Steve|title=ARM System-on-Chip Architecture|year=2000|url=https://archive.org/details/armsystemonchipa00furb|url-access=limited|isbn=0201675196|page=[https://archive.org/details/armsystemonchipa00furb/page/n356 344]}}</ref> 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.

===Differences from ARM7 cores===
Key improvements over [[ARM7]] cores, enabled by spending more transistors, include:<ref>"Performance of the ARM9TDMI and ARM9E-S cores compared to the ARM7TDMI core", Issue 1.0, dated 9 February 2000, ARM Ltd.</ref>

* 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 [[Advanced Microcontroller Bus Architecture#Advanced High-performance Bus (AHB)|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 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 [[Intellectual property|IP]] as [[Logic synthesis|synthesizable]] [[Register transfer level|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==
{| class="wikitable" border="1" style="float:right; margin-left:9px;"
|-
! 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 [[multicore processor]]s support software written using either the asymmetric ([[Asymmetric multiprocessing|AMP]]) or symmetric ([[Symmetric multiprocessing|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.<ref>{{cite web|url=http://www.arm.com/products/processors/cortex-a/arm-mpcore-sample-code.php|title=MPCore Sample Code|archive-url=https://web.archive.org/web/20150411211220/http://www.arm.com/products/processors/cortex-a/arm-mpcore-sample-code.php|archive-date=11 April 2015}}</ref>

==={{anchor|ARM920T|ARM922T|ARM940T}}ARM9TDMI===
<!-- Header used in redirects -->
ARM9TDMI is a successor to the popular [[ARM7TDMI]] core, and is also based on the [[ARMv4T]] architecture.  Cores based on it have five-stage pipeline (fetch, decode, execute, data memory access, register write)<ref>https://www.ecb.torontomu.ca/~courses/ee8205/Data-Sheets/ARM/ARM9TDMI.pdf</ref>, support both 32-bit ARM and 16-bit Thumb instruction sets and include:
* ARM920T with 16&nbsp;KB each of I/D cache and an [[Memory management unit|MMU]]
* ARM922T with 8&nbsp;KB each of I/D cache and an MMU
* ARM940T with cache and a Memory Protection Unit (MPU)

==={{anchor|ARM9E-S|ARM9EJ-S}}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.
* ARM926EJ-S with ARM [[Jazelle]] technology, which enables the direct execution of 8-bit [[Java bytecode]] in hardware, and an MMU
* ARM946
* ARM966
* ARM968
The [[TI-Nspire CX]] (2011) and CX II (2019) graphing calculators use an ARM926EJ-S processor, clocked at 132 and 396&nbsp;MHz respectively.<ref>{{Cite web|title=Teardown Tuesday: Graphing Calculator - News|url=https://www.allaboutcircuits.com/news/teardown-tuesday-graphing-calculator/|access-date=2021-07-12|website=www.allaboutcircuits.com|language=en}}</ref>

==Chips==
[[File:DSi pcb front.jpg|thumb|right|[[Nintendo DSi]] has a chip with an ARM9 and ARM7 core]]
[[File:Lego Mindstorms EV3 brick.jpg|thumb|[[Lego Mindstorms EV3]] brick has an ARM9 TI [[Sitara ARM Processor|Sitara AM1x]]]]
[[File:Samsung SGH-D900i - NXP ARM 5230EL-247-4A on motherboard-8858.jpg|thumb|ARM946E-S baseband processor on a [[Samsung SGH-D900]] phone]]

;ARM920T
* [[Atmel]] AT91RM9200<ref name="Atmel-Legacy-Web">[http://www.atmel.com/products/microcontrollers/arm/legacy_products.aspx Atmel Legacy ARM-Based Solutions; Atmel.]</ref>
* [[Cirrus Logic]] EP9315 ARM9 CPU, 200&nbsp;MHz
* [[NXP]] [[i.MX|i.MX1]]
* [[Samsung]] S3C2410, S3C2440, S3C2442, S3C2443

;ARM922T[[File:TomTom XL (4ET03) - board - Samsung S3C2416XH-26-9788.jpg|thumb|Samsung S3C2416XH-26]]
* [[Micrel]]/Kendin KS8695
* [[NXP]] LH7A4xx

;ARM925T
* [[Texas Instruments]] OMAP 1510

;ARM926EJ-S
* ASPEED AST2400
* [[Cypress Semiconductor]] EZ-USB FX3
* [[Microchip Technology]] (former [[Atmel]]) AT91SAM9260,<ref name="Atmel-Legacy-Web"/> AT91SAM9G,<ref>[http://www.atmel.com/products/microcontrollers/arm/sam9g.aspx SAM9G ARM9 Microcontrollers; Atmel.]</ref> AT91SAM9M,<ref>[http://www.atmel.com/products/microcontrollers/arm/sam9m.aspx SAM9M ARM9 Microcontrollers; Microchip.]</ref> AT91SAM9N/CN,<ref>[http://www.atmel.com/products/microcontrollers/arm/sam9n.aspx SAM9N/CN ARM9 Microcontrollers; Atmel.]</ref> AT91SAM9R/RL,<ref>[http://www.atmel.com/products/microcontrollers/arm/sam9r.aspx SAM9R/RL ARM9 Microcontrollers; Atmel.]</ref> AT91SAM9X,<ref>[http://www.atmel.com/products/microcontrollers/arm/sam9x.aspx SAM9X ARM9 Microcontrollers; Atmel.]</ref> AT91SAM9XE<ref>[http://www.atmel.com/products/microcontrollers/arm/sam9xe.aspx SAM9XE ARM9 Microcontrollers; Atmel.]</ref> (see [[AT91SAM9]])
* [[Nintendo]] [[Hollywood (graphics chip)#Starlet|Starlet]] ([[Wii]] coprocessor)<ref>{{cite web |title=Hardware/Starlet |url=https://wiibrew.org/wiki/Hardware/Starlet |website=Wiibrew |access-date=14 June 2020 |archive-url=https://web.archive.org/web/20200516131251/https://wiibrew.org/wiki/Hardware/Starlet |archive-date=16 May 2020 |url-status=live}}</ref>
* [[Nuvoton]] NUC900
* [[NXP]] (former [[Freescale Semiconductor]]) i.MX2 Series,<ref>[http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-processors/i.mx28-applications-processors-integrated-power-management-unit-pmu-arm9-core:IMX28_FAMILY i.MX28 Applications Processors; NXP.]</ref> (see [[I.MX]]), [[LPC3100]] and [[LPC3200]] Series<ref>{{Cite web|url=https://www.nxp.com/products/processors-and-microcontrollers/arm-based-processors-and-mcus/lpc-cortex-m-mcus/lpc3000-arm9-mpus:MC_71572|title=LPC3100/200 Series: Arm9-based microcontrollers{{!}}NXP|website=www.nxp.com|access-date=2018-07-27}}</ref>
* Samsung S3C2412, S3C2416, S3C2450
* [[Spreadtrum]] SC6531, SC7701B
* STMicroelectronics [[Nomadik]]
* Texas Instruments [[OMAP]] 850, 750, 733, 730, 5912 (also 5948, which is a customer specific version of it, made for Bosch), 1610
* [[Texas Instruments]] [[Sitara ARM Processor|Sitara]] AM1x, OMAP L137/L138, Davinci DA830/DA850/DM355/DM365
* HP [[HP Integrated Lights-Out|iLO 4]]<ref>{{cite web|url=https://csrc.nist.gov/csrc/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp2574.pdf|title=iLO 4 Cryptographic Module FIPS 140-2 Non-Proprietary Security Policy|date=10 February 2016|publisher=Hewlett Packard Enterprise}}</ref> baseboard management controller
*5V Technologies 5VT1310/1312/1314
* [[STMicroelectronics]] SPEAr300/600<ref>{{Cite web|url=https://www.st.com/en/microcontrollers-microprocessors/spear-arm-926-microprocessors.html|title = SPEAr ARM 926 Microprocessors - STMicroelectronics}}</ref>
* [[VIA Technologies|VIA]] [[WonderMedia]] 8505 and 8650

;ARM940T
* [[Conexant]] [[CX22490]] STB SoC

;ARM946E-S
* [[Nintendo]] NTR-CPU ([[Nintendo DS]] CPU), TWL-CPU ([[Nintendo DSi]] CPU; same as the DS but clocked at 133&nbsp;MHz instead of 67&nbsp;MHz)<ref>[http://problemkaputt.de/gbatek.htm#armcp15idcodes GBATEK - GBA/NDS Technical Info -  ARM CP15 ID Codes; Martin Korth]</ref>
* NXP [[Nexperia (processor)|Nexperia]] PNX5230

;{{anchor|ARM966E|ARM966ES|ARM966E-S}}ARM966E-S
* [[LSI Corporation|LSI Logic]] LSI53C1030
* [[STMicroelectronics]] STR9<ref>[http://www.st.com/en/microcontrollers/str9-32-bit-arm9-mcus.html?querycriteria=productId=LN1171 STR9 ARM9 Microcontrollers; STMicroelectronics.]</ref>

;ARM968E-S
* [[NXP Semiconductors]] [[LPC2900]]

;Unreferenced ARM9 core
* [[Anyka]] AK32xx
* [[Atmel]] [[AT91CAP9]]
* [[CSR plc|CSR]] Quatro 4300
* Centrality Atlas III
* [[Digi International|Digi]] NS9215, NS9210<ref>{{cite web|url=https://www.digi.com/pdf/pb_ns9210_9215.pdf|title=NS9210/NS9215 32-bit NET+ARM Processor Family|publisher=[[Digi International]]}}</ref>
* [[HiSilicon]] Kirin K3V1
* [[Infineon Technologies]] S-GOLDlite PMB 8875
* [[LeapFrog Enterprises|LeapFrog]] LF-1000
* [[NXP Semiconductors]] (former [[Freescale Semiconductor]]) [[I.MX|i.MX1x]]
* [[MediaTek]] MT1000, MT6235-39, MT6268, MT6516
* PRAGMATEC RABBITV3 (ARM920T rev 0 (v4l)) used in [[Nabaztag#Karotz|Karotz]]) 
* [[Qualcomm]] MSM6xxx
* [[Qualcomm Atheros]] AR6400
* [[Texas Instruments]] TMS320DM365/TMS320DM368 ARM9EJ-S
* Zilog Encore! 32

==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):

# IC manufacturer marketing slides.
# IC manufacturer datasheets.
# IC manufacturer reference manuals.
# ARM core reference manuals.
# 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==
{{Portal|Electronics}}
{{See also|List of ARM Cortex-M development tools}}
* [[ARM architecture]]
* [[List of ARM microarchitectures|List of ARM architectures and cores]]
* [[JTAG]]
* [[Interrupt]], [[Interrupt handler]]
* [[Real-time operating system]], [[Comparison of real-time operating systems]]

==References==
{{Reflist|30em}}

==External links==
{{Commons category multi|ARM9}}
;ARM9 official documents
* {{Official website|http://www.arm.com/products/processors/classic/arm9/index.php|ARM9 official website}}
* Architecture Reference Manual: [https://silver.arm.com/download/ARM_Architecture/AR550-DA-70002-r0p0-00rel0/DDI%2001001.pdf ARMv4/5/6]
* Core Reference Manuals: [http://infocenter.arm.com/help/topic/com.arm.doc.ddi0240b/DDI0240A.pdf ARM9E-S], [http://infocenter.arm.com/help/topic/com.arm.doc.ddi0222b/DDI0222.pdf ARM9EJ-S],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0180a/DDI0180.pdf ARM9TDMI],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0151c/ARM920T_TRM1_S.pdf ARM920T],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0184b/DDI0184.pdf ARM922T],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0198e/DDI0198E_arm926ejs_r0p5_trm.pdf ARM926EJ-S],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0144b/940T_TRM_S.pdf ARM940T],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0201d/DDI0201D_arm946es_r1p1_trm.pdf ARM946E-S],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0213e/ARM966E-S_TRM.pdf ARM966E-S],[http://infocenter.arm.com/help/topic/com.arm.doc.ddi0311d/DDI0311.pdf ARM968E-S]
* Coprocessor Reference Manuals: [http://infocenter.arm.com/help/topic/com.arm.doc.ddi0238c/DDI0238C_vfp9s_r0p2_trm.pdf VFP9-S (Floating-Point)], [http://infocenter.arm.com/help/topic/com.arm.doc.ddi0235c/DDI0235.pdf MOVE (MPEG4)]

;Quick Reference Cards
* Instructions: Thumb ([http://infocenter.arm.com/help/topic/com.arm.doc.qrc0006e/QRC0006_UAL16.pdf 1]), ARM and Thumb-2 ([http://infocenter.arm.com/help/topic/com.arm.doc.qrc0001m/QRC0001_UAL.pdf 2]), Vector Floating Point ([http://infocenter.arm.com/help/topic/com.arm.doc.qrc0007e/QRC0007_VFP.pdf 3])
* Opcodes: Thumb ([http://re-eject.gbadev.org/files/ThumbRefV2-beta.pdf 1], [http://www.mechcore.net/files/docs/ThumbRefV2-beta.pdf 2]), ARM ([http://re-eject.gbadev.org/files/armref.pdf 3], [http://www.mechcore.net/files/docs/armref.pdf 4]), GNU Assembler Directives [http://re-eject.gbadev.org/files/GasARMRef.pdf 5].

{{Clear}}
{{Classic ARM-based chips|state=expanded}}
{{Embedded ARM-based chips}}
{{Microcontrollers}}
{{Clear}}

{{DEFAULTSORT:Arm9}}

[[Category:ARM processors]]
[[Category:32-bit microprocessors]]