Architecture of 8051 Microcontroller.pdf

The 8051 microcontroller was invented in 1980's by Intel. 
Its foundation is based on Harvard architecture and this microcontroller was developed principally for bringing it to be used in Embedded Systems.
At first it was created by using NMOS technology but the use of NMOS(N-channel metal-oxide semiconductor)  consumed more power to work therefore Intel re-launch the microcontroller 8051 using CMOS(complementary metal-oxide semiconductor) technology and new edition came up with edition of letter 'C' in the title name, therefore the new modified version of microcontroller is called by name 80C51.
The 8051 microcontroller programming is performed in embedded C language using Keil software.

1. 8051 Architecture
Mrs. Hezal Lopes
Assistant Professor
DJSCE, Vile Parle(W)

2. TheMicrocontroller Architecture:
•Introduction to 8051 Microcontroller,
•Architecture,
•Interrupts of 8051

3. •The8051microcontrollerwasinventedin1980'sbyIntel.
•ItsfoundationisbasedonHarvardarchitectureandthismicrocontrollerwasdeveloped
principallyforbringingittobeusedinEmbeddedSystems.
•AtfirstitwascreatedbyusingNMOStechnologybuttheuseofNMOS(N-channelmetal-oxide
semiconductor)consumedmorepowertoworkthereforeIntelre-launchthemicrocontroller
8051usingCMOS(complementarymetal-oxidesemiconductor)technologyandneweditioncame
upwitheditionofletter'C'inthetitlename,thereforethenewmodifiedversionof
microcontrolleriscalledbyname80C51.
•The8051microcontrollerprogrammingisperformedinembeddedClanguageusingKeil
software.

4. Features of 8051 Microcontroller:
•Ithavingfourregisterbanks
•64Kbyteson-chipprogrammablememory(ROM)
•128byteson-chipdatamemory(RAM)
•Addressbusis16-bitunidirectional
•Databusis8-bitbidirectional
•128userdefinedflags
•16bittimers
•32generalpurposeregisterseachof8-bit
•8051microcontrolleroffersanumberofspecialfeaturessuchasADC,UARTs,Op-amp,etc.

6. Application of 8051 Microcontroller
Examplesofembeddedsystemsincludethecontrollersinwashingmachines,theenginemanagementsystemsincars,andthe
flightcontrolsystemsinaircraft.
•Home automation: The 8051 microcontroller can be used in home automation systems to control lighting, temperature,
and security systems.
•Industrial control: The 8051 microcontroller is used in industrial control applications tocontrol processes, machinery, and
equipment.It can also be used to monitor and control temperature, pressure, and other environmental factors.
•Robotics: The 8051 microcontroller is used in robotics applications to control the movement of robots, sensors, and
actuators.
•Automotive: The 8051 microcontroller is used in the automotive industry for engine control, anti-lock braking systems,
airbag control, and other applications.
•Medical devices: The 8051 microcontroller is used in medical devices for patient monitoring, drug delivery systems,and
other applications.
•Communication systems: The 8051 microcontroller is used in communication systems for data transmission, signal
processing, and other applications.
•Consumer electronics: The 8051 microcontroller is used in consumer electronics such as remote controls, digital cameras,
and smart home devices.

7. •WhatisMicrocontroller?
•Amicrocomputermadeonasinglesemiconductorchipiscalledsingle-chipmicrocomputer.Since,singlechip
microcomputersaregenerallyusedincontrolapplications,theyarealsocalledmicrocontrollers.
•MicrocontrollercontainsallessentialcomponentsofamicrocomputersuchasCPU,RAM,ROM/EPROM,I/Olinesetc.
SomesinglechipmicrocontrollerscontaindevicestoperformspecificfunctionssuchasDMAchannels,A/Dconverter,
serialport,pulsewidthmodulation,etc.

8. •8051Architecture
•In1980,Intelintroducedapowerful8051seriesof8-bitmicrocontrollers.
•Theyarethesecondgenerationof8-bitmicrocontrollers.
•The8051microcontrollersareusedforavarietyofapplicationsinvolvinglimitedcalculationsandrelativelysomecontrol
strategies.
•Theyareusedforindustrialandcommercialcontrolapplications,appliancescontrol,instrumentationetc.
•The8051containsBooleanprocessor,fullduplexserialportandpowersavingcircuitryinadditionto
essentialcomponentssuchas8-bitCPU,RAM,ROM/EPROM/OTPROM,timer/counterandparallelI/Olines.

9. 8051MicrocontrollerArchitecture/BlockDiagram

10. •Basiccomponentspresentinternallyinside8051Microcontrollerarchitectureare:
•CPU(CentralProcessingUnit):
•CPUactasamindofanyprocessingmachine.
•Itsynchronizesandmanagesallprocessesthatarecarriedoutinmicrocontroller.
•UserhasnopowertocontrolthefunctioningofCPU.
•ItinterpretstheprogramstoredinROMandcarriesoutfromstorageandthenperformsitprojectedduty.
•CPUmanagethedifferenttypesofregistersavailablein8051microcontroller.

11. Interrupts:
•Interruptsisasub-routinecallthatgivenbythemicrocontrollerwhensomeotherprogramwith
highpriorityisrequestforacquiringthesystembusestheninterruptsoccurincurrent
runningprogram.
•Interruptsprovideamethodtopostponeordelaythecurrentprocess,performsasub-routine
taskandthenrestartthestandardprogramagain.
•Typesofinterruptin8051Microcontroller:
•Let'sseethefivesourcesofinterruptsin8051Microcontroller:
•Timer0overflowinterrupt-TF0
•Timer1overflowinterrupt-TF1
•Externalhardwareinterrupt-INT0
•Externalhardwareinterrupt-INT1
•Serialcommunicationinterrupt-RI/TI

13. IP (Interrupt Priority) Register
•Wecanchangetheprioritylevelsoftheinterruptsbychangingthe
correspondingbitintheInterruptPriority(IP)registerasshowninthe
followingfigure.
•Alowpriorityinterruptcanonlybeinterruptedbythehighpriorityinterrupt,
butnotinterruptedbyanotherlowpriorityinterrupt.
•Iftwointerruptsofdifferentprioritylevelsarereceivedsimultaneously,the
requestofhigherprioritylevelisserved.
•Iftherequestsofthesameprioritylevelsarereceivedsimultaneously,then
theinternalpollingsequencedetermineswhichrequestistobeserviced.

15. •Memory:
•ForoperationMicro-controllerrequiredaprogram.
•Thisprogramguidesthemicrocontrollertoperformthespecifictasks.
•Thisprograminstalledinmicrocontrollerrequiredsomeonchipmemoryforthestorageoftheprogram.
•Microcontrolleralsorequiredmemoryforstorageofdataandoperandsfortheshortduration.
•Inmicrocontroller8051thereiscodeorprogrammemoryof4KBthatisithas4KBROManditalsocompriseofdatamemory
(RAM)of128bytes.
•Oscillator:
•As the microcontroller is digital circuittherefore it needs timer for their operation.
•To perform timer operation inside microcontroller it required externally connected or on-chip oscillator.
•Microcontroller is used inside an embedded system for managing the function of devices.
•Therefore, 8051 uses the two 16 bit counters and timers.
•For the operation of this timers and counters the oscillator is used inside microcontroller.

16. •Bus:Busisagroupofwireswhichusesasacommunicationcanaloractsasmeansofdatatransfer.
•Thedifferentbusconfigurationincludes8,16ormorecables.Therefore,abuscanbear8bits,16bitsalltogether.
•Typesofbusesin8051Microcontroller:
•Let'sseethetwotypesofbususedin8051microcontroller:
•AddressBus:8051microcontrollersisconsistingof16bitaddressbus.Itisgenerallybeusedfortransferringthedata
fromCentralProcessingUnittoMemory.
•Databus:8051microcontrollerisconsistingof8bitsdatabus.Itisgenerallybeusedfortransferringthedatafrom
oneperipheralspositiontootherperipherals.

17. Thank You