转速测量附录.docx
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转速测量附录.docx
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转速测量附录
附录A系统总电路图
附录B系统总程序清单
#include
#defineucharunsignedchar
#defineuintunsignedint
uintmm=1234;
ucharcodetable[]={0xc0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,};
delay(uintm)
{uinti,j;
for(i=m;i>0;i--)
for(j=60;j>0;j--);
}
xian_shi()
{ucharqian,bei,shi,ge;
uintjj;
jj=mm;
jj*=20;
//jj+=1;
qian=jj/1000;
bei=jj%1000/100;
shi=jj%100/10;
ge=jj%10;
P2=0x10;
P0=table[qian];
delay
(1);
//P2=0;
P2=0x20;
P0=table[bei];
delay
(1);
//P2=0;
P2=0x40;
P0=table[shi];
delay
(1);
//P2=0;
P2=0x80;
P0=table[ge];
delay
(1);
//P2=0;
}
timer_init()//定时器计数器初始化函数
{EA=1;
ET0=1;
ET1=1;
TMOD=0X51;
TH0=(65535-50000)/256;
TL0=(65535-50000)%256;
TH1=0;
TL1=0;
TR0=1;
TR1=1;
}
main()
{
timer_init();
P0=0;//开始数码管不显示
while
(1)
{
xian_shi();
delay
(2);//数码管刷新时间单位毫秒
}
}
voidtimer0()interrupt1
{TR0=0;
TR1=0;
TH0=(65535-50000)/256;
TL0=(65535-50000)%256;
mm=0;
mm|=TH1;
mm=(mm<<8)|TL1;
//mm-=55536;
TH1=0;
TL1=0;
TR0=1;
TR1=1;
}
voidtimer1()interrupt3//显示0000说明出错
{TR1=0;
TR0=0;
mm=0;
//TH1=0;
//TL1=0;
//TR1=1;
}
Electricboilertemperaturesystem
1.MCU
Amicrocontroller(orMCU)isacomputer-on-a-chip.Itisatypeofmicroprocessoremphasizingself-sufficiencyandcost-effectiveness,incontrasttoageneral-purposemicroprocessor(thekindusedinaPC).
Themajorityofcomputersystemsinusetodayareembeddedinothermachinery,suchastelephones,clocks,appliances,vehicles,andinfrastructure.Anembeddedsystemusuallyhasminimalrequirementsformemoryandprogramlengthandmayrequiresimplebutunusualinput/outputsystems.Forexample,mostembeddedsystemslackkeyboards,screens,disks,printers,orotherrecognizableI/Odevicesofapersonalcomputer.Theymaycontrolelectricmotors,relaysorvoltages,andreadswitches,variableresistorsorotherelectronicdevices.Often,theonlyI/Odevicereadablebyahumanisasinglelight-emittingdiode,andseverecostorpowerconstraintscaneveneliminatethat.
Incontrasttogeneral-purposeCPUs,microcontrollersdonothaveanaddressbusoradatabus,becausetheyintegratealltheRAMandnon-volatilememoryonthesamechipastheCPU.Becausetheyneedfewerpins,thechipcanbeplacedinamuchsmaller,cheaperpackage.
Integratingthememoryandotherperipheralsonasinglechipandtestingthemasaunitincreasesthecostofthatchip,butoftenresultsindecreasednetcostoftheembeddedsystemasawhole.(EvenifthecostofaCPUthathasintegratedperipheralsisslightlymorethanthecostofaCPU+externalperipherals,havingfewerchipstypicallyallowsasmallerandcheapercircuitboard,andreducesthelaborrequiredtoassembleandtestthecircuitboard).Thistrendleadstodesign.
Amicrocontrollerisasingleintegratedcircuit,commonlywiththefollowingfeatures:
centralprocessingunit-rangingfromsmallandsimple4-bitprocessorstosophisticated32-or64-bitprocessors
input/outputinterfacessuchasserialports(UARTs)
otherserialcommunicationsinterfaceslikeI²C,SerialPeripheralInterfaceandControllerAreaNetworkforsysteminterconnectperipheralssuchastimersandwatchdogRAMfordatastorageROM,EPROM,EEPROMorFlashmemoryforprogramstorageclockgenerator-oftenanoscillatorforaquartztimingcrystal,resonatororRCcircuitmanyincludeanalog-to-digitalconverters.
ThisintegrationdrasticallyreducesthenumberofchipsandtheamountofwiringandPCBspacethatwouldbeneededtoproduceequivalentsystemsusingseparatechipsandhaveprovedtobehighlypopularinembeddedsystemssincetheirintroductioninthe1970s.
SomemicrocontrollerscanaffordtouseaHarvardarchitecture:
separatememorybusesforinstructionsanddata,allowingaccessestotakeplaceconcurrently.
Thedecisionofwhichperipheraltointegrateisoftendifficult.TheMicrocontrollervendorsoftentradeoperatingfrequenciesandsystemdesignflexibilityagainsttime-to-marketrequirementsfromtheircustomersandoveralllowersystemcost.Manufacturershavetobalancetheneedtominimizethechipsizeagainstadditionalfunctionality.
Microcontrollerarchitecturesareavailablefrommanydifferentvendorsinsomanyvarietiesthateachinstructionsetarchitecturecouldrightlybelongtoacategoryoftheirown.Chiefamongthesearethe8051,Z80andARMderivatives.[citationneeded]
Amicrocontroller(alsoMCUorµC)isafunctionalcomputersystem-on-a-chip.Itcontainsaprocessorcore,memory,andprogrammableinput/outputperipherals.
MicrocontrollersincludeanintegratedCPU,memory(asmallamountofRAM,programmemory,orboth)andperipheralscapableofinputandoutput.
Itemphasizeshighintegration,incontrasttoamicroprocessorwhichonlycontainsaCPU(thekindusedinaPC).Inadditiontotheusualarithmeticandlogicelementsofageneralpurposemicroprocessor,themicrocontrollerintegratesadditionalelementssuchasread-writememoryfordatastorage,read-onlymemoryforprogramstorage,Flashmemoryforpermanentdatastorage,peripherals,andinput/outputinterfaces.Atclockspeedsofaslittleas32KHz,microcontrollersoftenoperateatverylowspeedcomparedtomicroprocessors,butthisisadequatefortypicalapplications.Theyconsumerelativelylittlepower(milliwattsorevenmicrowatts),andwillgenerallyhavetheabilitytoretainfunctionalitywhilewaitingforaneventsuchasabuttonpressorinterrupt.Powerconsumptionwhilesleeping(CPUclockandperipheralsdisabled)maybejustnanowatts,makingthemidealforlowpowerandlonglastingbatteryapplications.
Microcontrollersareusedinautomaticallycontrolledproductsanddevices,suchasautomobileenginecontrolsystems,remotecontrols,officemachines,appliances,powertools,andtoys.Byreducingthesize,cost,andpowerconsumptioncomparedtoadesignusingaseparatemicroprocessor,memory,andinput/outputdevices,microcontrollersmakeiteconomicaltoelectronicallycontrolmanymoreprocesses.
Themajorityofcomputersystemsinusetodayareembeddedinothermachinery,suchasautomobiles,telephones,appliances,andperipheralsforcomputersystems.Thesearecalledembeddedsystems.Whilesomeembeddedsystemsareverysophisticated,manyhaveminimalrequirementsformemoryandprogramlength,withnooperatingsystem,andlowsoftwarecomplexity.Typicalinputandoutputdevicesincludeswitches,relays,solenoids,LEDs,smallorcustomLCDdisplays,radiofrequencydevices,andsensorsfordatasuchastemperature,humidity,lightleveletc.Embeddedsystemsusuallyhavenokeyboard,screen,disks,printers,orotherrecognizableI/Odevicesofapersonalcomputer,andmaylackhumaninteractiondevicesofanykind.
Itismandatorythatmicrocontrollersproviderealtimeresponsetoeventsintheembeddedsystemtheyarecontrolling.Whencertaineventsoccur,aninterruptsystemcansignaltheprocessortosuspendprocessingthecurrentinstructionsequenceandtobeginaninterruptserviceroutine(ISR).TheISRwillperformanyprocessingrequiredbasedonthesourceoftheinterruptbeforereturningtotheoriginalinstructionsequence.Possibleinterruptsourcesaredevicedependent,andoftenincludeeventssuchasaninternaltimeroverflow,completingananalogtodigitalconversion,alogiclevelchangeonaninputsuchasfromabuttonbeingpressed,anddatareceivedonacommunicationlink.Wherepowerconsumptionisimportantasinbatteryoperateddevices,interruptsmayalsowakeamicrocontrollerfromalowpowersleepstatewheretheprocessorishalteduntilrequiredtodosomethingbyaperipheralevent.
Microcontrollerprogramsmustfitintheavailableon-chipprogrammemory,sinceitwouldbecostlytoprovideasystemwithexternal,expandable,memory.Compilersandassemblylanguageareusedtoturnhigh-levellanguageprogramsintoacompactmachinecodeforstorageinthemicrocontroller'smemory.Dependingonthedevice,theprogrammemorymaybepermanent,read-onlymemorythatcanonlybeprogrammedatthefactory,orprogrammemorymaybefield-alterableflashorerasableread-onlymemory.
Sinceembeddedprocessorsareusuallyusedtocontroldevices,theysometimesneedtoacceptinputfromthedevicetheyarecontrolling.Thisisthepurposeoftheanalogtodigitalconverter.Sinceprocessorsarebuilttointerpretandprocessdigitaldata,i.e.1sand0s,theywon'tbeabletodoanythingwiththeanalogsignalsthatmaybebeingsenttoitbyadevice.Sotheanalogtodigitalconverterisusedtoconverttheincomingdataintoaformthattheprocessorcanrecognize.Thereisalsoadigitaltoanalogconverterthatallowstheprocessortosenddatatothedeviceitiscontrolling.
Inadditiontotheconverters,manyembeddedmicroprocessorsincludeavarietyoftimersaswell.OneofthemostcommontypesoftimersistheProgrammableIntervalTimer,orPITforshort.APITjustcountsdownfromsomevaluetozero.Onceitreacheszero,itsendsaninterrupttotheprocessorindicatingthatithasfinishedcounting.Thisisusefulfordevicessuchasthermostats,whichperiodicallytestthetemperaturearoundthemtoseeiftheyneedtoturntheairconditioneron,theheateron,etc.
TimeProcessingUnitorTPUforshort.Isessentiallyjustanothertimer,butmoresophisticated.Inadditiontocountingdown,theTPUcandetectinputevents,generateoutputevents,andotherusefuloperations.
DedicatedPulseWidthModulation(PWM)blockmakesitpossiblefortheCPUtocontrolpowerconverters,resistiveloads,motors,etc.,withoutusinglotsofCPUresourcesintighttimerloops.
UniversalAsynchronousReceiver
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