Chapters1and3ARMProcessorArchitecture

EmbeddedSystemswithARMCortext-MUpdated:Monday,February5,2018

ALittleaboutARM– Thecompany

• Originally AcornRISCMachine(ARM)• Later AdvancedRISCMachine• ThenitbecameARMLtdownedbyARMHoldings(parentcompany)• In2016SoftBank boughtARMfor$31billion• ARM:

• Developsthearchitectureandlicensesittoothercompanies• Othercompaniesdesigntheirownproductsthatimplementoneofthosearchitectures — including systems-

on-chips (SoC)and systems-on-modules (SoM)thatincorporatememory,interfaces,radios,etc.• Italsodesigns coresthatimplementthis instructionset andlicensesthesedesignstoanumberofcompanies

thatincorporatethosecoredesignsintotheirownproducts.• ARMProcessors

• RISCbasedprocessors• In2010alone,6.1billionARM-basedprocessor,representing95%ofsmartphones,35% ofdigitaltelevisions

andset-topboxesand10% ofmobilecomputers• over100billionARMprocessorsproducedasof2017• Themostwidelyused instructionsetarchitecture intermsofquantityproduced

https://en.wikipedia.org/wiki/ARM_architecture

https://en.wikipedia.org/wiki/ARM_architecture

M

R

ARMFamilyandArchitecture

CPU

ARMFAMILYTREE

CORTEX-

CORTEX-

CORTEX-

ARMCortexProcessors

6

• ARMCortex-A family:• Applicationsprocessors• SupportOSandhigh-performanceapplications

• SuchasSmartphones,SmartTV

• ARMCortex-R family:• Real-timeprocessorswithhighperformanceandhighreliability

• Supportreal-timeprocessingandmission-criticalcontrol

• ARMCortex-M family:• Microcontroller• Cost-sensitive,supportSoC

CORTEX-• Cortex-Misagreattrade-offbetweenperformance,cost,efficiency;usedforIoT,variousapplications.

• Hason-chipperipherals• CoreislicensedbyARM

HarvardArchitecture

CORTEX-M:CORE+Peripherals

• Core• Memory

• FLASH:Non-Volatile/InstructionmemorySRAM/DRAM:Volatile/datamemory

• Processor• ALU• ProcessorControlUnit(CPU)• Registers

• SpecialPurposeRegisters• GeneralPurposeRegisters

• Buses• DataBus• InstructionBus• Busbridgetoconnectdiff.buses• AdvancedHigh-performanceBus(AHB)• AdvancedPeripheralBus(APB)

• GPIO

• Peripherals• ADC• LCDController• SPI• I2C• Etc.

9

CoreArchitecture

Instructionsanddataarestoredinthesamememory.

Von-Neumann HarvardDataandinstructionsarestoredintoseparatememories.

• Faster• Moreenergyefficient• Differentbussizes

• Simpleandinexpensive• Accesstodataorinstruction,oneatatime

10

CoreArchitecture

Instructionsanddataarestoredinthesamememory.

Von-Neumann HarvardDataandinstructionsarestoredintoseparatememories.

ARMSimplifiedBlockDiagramSystemonChip(SoC)

http://www.microdigitaled.com/ARM/ASM_ARM/PowerPoints/ARM_ASM_ppts.htm

ARMCortex-M4Organization(STM32L4)

12

System-on-a-chip

Instructions

System Bus

Inte

rrup

t Con

trol

ler

(NVI

C)

Memory Protection Unit (MPU)

Instruction Bus

Data Bus

Interrupts`

Mem

ory

Inte

rfac

e

Cortex-M4 Processor Core

SW/JTAG

Inst

ruct

ion

Fetc

h U

nit

Inst

ruct

ion

Dec

oder

ALU

Proc

esso

r Con

trol

U

nit

Trac

e &

Deb

ug

Inte

rfac

e

Flash Memory

AHB to APB Bridge 1

AHB to APB Bridge 2

APB1

ABP2

LCDTIM2TIM3TIM4TIM6TIM7USART2USART3USART4USART5LPUART1

SPI2SPI3I2C1/SMBUSI2C2/SMBUSI2C3/SMBUSUSB 2.0 FSbxCANSWPMI1LPTIM1LPTIM2OpAmp

GPIO Port AGPIO Port BGPIO Port CGPIO Port DGPIO Port EGPIO Port FGPIO Port GGPIO Port H

EXTIWKUPTIM1/PWMTIM8/PWMTIM15TIM16TIM17USART1

SPI1SAI1SAI2DFSDMCOMP1COMP2Firewall

AHB

Bus

Mat

rix

Direction Memory Access (DMA)

Controllers

DataSRAM

Advanced Peripheral Bus

(APB)

Advanced High-performance Bus

(AHB)

FPU

(opt

iona

l)

Sing

le In

stru

ctio

n M

ultip

le D

ata

(DSP

)

NotethattheKitweareusingHasanSTM32F401

HarvardBasedArchitecture

GeneralPurposeIO

Memory• Memoryisarrangedasaseriesof“locations”

• Eachlocationhasaunique“address”• Eachlocationholdsabyte(byte-addressable)• e.g.thememorylocationataddress0x080001B0containsthebytevalue0x70,i.e.,112

• Thenumberoflocationsinmemoryislimited• e.g.4GBofRAM• 1 Gigabyte(GB)=230 bytes• 232 locationsè 4,294,967,296locations!

• Valuesstoredateachlocationcanrepresenteitherprogramdataorprograminstructions

• e.g.thevalue0x70mightbethecodeusedtotelltheprocessortoaddtwovaluestogether

13

70 BC1801A0

0x00000000

0xFFFFFFFF

0x080001B00x080001AF0x080001AE0x080001AD0x080001AC

Memory

AddressData8 bits 32 bits

MemoryMapping• Answerthefollowingquestions:

• WhatisthesizeoftheEEPROM?• WhatisthesizeoftheFlash?• WhichMemoryportionisnon-volatile?• WhatdoesSRAMgenerallyusedforinanARMcoreprocessor?

• Whereis0x743address?• Whereis0x1000ABaddress?

ARMRegisterandALU16ProcessorRegisters13forgeneralpurpose3forspecificpurpose

ProcessorRegisters

R0R1R2R3R4R5R6R7R8R9

R10R11R12

R13 (SP)R14 (LR)R15 (PC)

32 bits

CONTROLFAULTMASK

PRIMASKBASEPRI

R13 (MSP) R13 (PSP)

xPSR

Low Registers

High Registers

32 bits

SpecialPurposeRegister

GeneralPurposeRegister

16

} Fastestwaytoreadandwrite} Registersarewithintheprocessorchip} Aregisterstores32-bitvalue} CortexM(STM32L)has

} R0-R12:13 general-purposeregisters} R13:Stackpointer(ShadowofMSPorPSP)} R14:Linkregister(LR)} R15:Programcounter(PC)} Specialregisters(xPSR,BASEPRI,PRIMASK,etc.)-

morelater

ProgramExecution• ProgramCounter(PC)isaregisterthatholdsthememoryaddressofthenextinstructiontobefetchedfromthememory.

4770 2000188B22012100

0x080001B40x080001B20x080001B00x080001AE0x080001AC

PC

MemoryAddress

17

PC=0x080001B0Instruction= 188B or 2000188B or 8B180020

MemoryContentàNextInstruction

Three-statepipeline:Fetch,Decode,Execution• Pipeliningallowshardwareresourcestobefullyutilized• One32-bitinstructionortwo16-bitinstructionscanbefetched.

18

Pipelineof32-bitinstructions

1.FetchinstructionatPCaddress

2.Decodethe

instruction

3.Executethe

instruction

LoadingCodeandDataintoMemory

19

SRAM

ARMRegisterandALU

Machinecodesarestoredinmemory

r15r14r13r12r11r10r9r8r7r6r5r4r3r2r1r0

ALU47702000188B22012100

pclrsp

0x00000000

0xFFFFFFFF

0x080001B40x080001B20x080001B00x080001AE0x080001AC

Registers Memory

AddressData

CPU21

FetchInstruction:pc=0x08001ACDecodeInstruction:2100=MOVSr1,#0x00

0x080001ACr15r14r13r12r11r10r9r8r7r6r5r4r3r2r1r0

ALU47702000188B22012100

pclrsp

0x00000000

0xFFFFFFFF

Registers Memory

AddressData

CPU

0x080001B40x080001B20x080001B00x080001AE0x080001AC

22

ExecuteInstruction:MOVSr1,#0x00

0x080001AC

0x00000000

r15r14r13r12r11r10r9r8r7r6r5r4r3r2r1r0

ALU47702000188B22012100

pclrsp

0x00000000

0xFFFFFFFF

Registers Memory

AddressData

CPU

0x080001B40x080001B20x080001B00x080001AE0x080001AC

23

FetchNextInstruction:pc=pc+2Decode&Execute:2201=MOVSr2,#0x01

0x080001AE

0x00000001

0x00000000

r15r14r13r12r11r10r9r8r7r6r5r4r3r2r1r0

ALU47702000188B22012100

pclrsp

0x00000000

0xFFFFFFFF

Registers Memory

AddressData

CPU

0x080001B40x080001B20x080001B00x080001AE0x080001AC

24

FetchNextInstruction:pc=pc+2Decode&Execute:188B=ADDSr3,r1,r2

0x080001B0

0x00000001

0x00000001

0x00000000

r15r14r13r12r11r10r9r8r7r6r5r4r3r2r1r0

ALU47702000188B22012100

pclrsp

0x00000000

0xFFFFFFFF

Registers Memory

AddressData

CPU

0x080001B40x080001B20x080001B00x080001AE0x080001AC

25

FetchNextInstruction:pc=pc+2Decode&Execute:2000=MOVSr0,#0x00

0x080001B2

0x00000001

0x00000000

0x00000000

r15r14r13r12r11r10r9r8r7r6r5r4r3r2r1r0

ALU47702000188B22012100

pclrsp

0x00000000

0xFFFFFFFF

Registers Memory

AddressData

CPU

0x080001B40x080001B20x080001B00x080001AE0x080001AC

26

ARMApplications….

iPhone5Teardown

28http://www.ifixit.com

TheA6processoristhefirstAppleSystem-on-Chip(SoC)touseacustomdesign,basedofftheARMv7 instructionset.

iPhone6Teardown

29http://www.ifixit.com

TheA8processoristhefirst64-bitARMbasedSoC. ItsupportsARMA64,A32,andT32instructionset.

iPhone7Teardown

30

A10processor:• 64-bitsystemonchip(SoC)• ARMv8-Acore

AppleWatch

31

• AppleS1Processor• 32-bitARMv7-Acompatible• #ofCores:1• CMOSTechnology:28nm• L1cache 32KBdata• L2cache 256KB• GPU PowerVR SGX543

KindleHDFire

32http://www.ifixit.com

TexasInstrumentsOMAP4460dual-coreprocessor

FitbitFlexTeardown

33

STMicroelectronics32L151C6UltraLowPowerARMCortexM3 Microcontroller

NordicSemiconductornRF8001 BluetoothLowEnergyConnectivityIC

www.ifixit.com

SamsungGalaxyGear

• STMicroelectronicsSTM32F401BARM-CortexM4MCUwith128KBFlash

source:ifixit.com

34

PebbleSmartwatch

• STMicroelectronicsSTM32F205REARMCortex-M3MCU,withamaximumspeedof120MHz

source:ifixit.com

35

OculusVR

• Facebook’s$2BillionAcquisitionOfOculusin2014• STMicroelectronicsSTM32F072VBARMCortex-M0 32-bitRISCCoreMicrocontroller

source:ifixit.com

36

HTCVive

37

STMicroelectronics32F072R8ARMCortex-M0Microcontroller

source:ifixit.com

NestLearningThermostat

• STMicroelectronicsSTM32L151VBultra-low-power32MHzARMCortex-M3MCU

source:ifixit.com

38

SamsungGearFitFitnessTracker

• STMicroelectronicsSTM32F439ZI180MHz,32bitARMCortex-M4CPU

source:ifixit.com

39

ALittleAboutSTM32

• STM32 isafamilyof32-bit microcontroller integratedcircuits by STMicroelectronics

• TheSTM32chipsaregroupedintorelatedseriesthatarebasedaroundthesame 32-bit ARM processorcore,suchasthe Cortex-M7F, Cortex-M4F, Cortex-M3, Cortex-M0+,or Cortex-M0.

• Internally,eachmicrocontrollerconsistsoftheprocessorcore, staticRAM memory, flash memory,debugginginterface,andvariousperipherals.

https://en.wikipedia.org/wiki/STM32

STM32NucleoFamily

OtherARMChips