单片机原理及应用（双语版·新形态版） 课件 第8章MCS51与外部器件的接口设计

IntroductoryMicrocontrollerTheoryandApplicationsChapter8InterfacingtheMCS-51toElectronicDevicesInterfacingtoExternalDevices8051A-DconverterExternalmemory7-segmentdisplayI/OinterfaceLCDdisplayD-AconverterSteppermotoriButtonInterfacingtoExternalDevices8051A-DconverterExternalmemory7-segmentdisplayI/OinterfaceLCDdisplayD-AconverterSteppermotoriButtonParallelportsonthe8051P0P1P3P2CircuitofaPort1pin0TurnonCLRP1.00101WriteCircuitofaPort1pinWrite1TurnoffSETBP1.00110CircuitofaPort1pinRead1TurnoffSETBP1.01110CircuitofaPort1pinReadOnlyusedforlogicalinstructionsANL,ORL,XRLParallelportsonthe8051P0P1P3P2Alternatefunctions40239133843753663573483393210311130122913281427152616251724182319222021P1.0P1.1P1.2P1.3P1.4P1.5P1.6P1.7P2.7P2.6P2.5P2.4P2.3P2.2P2.1P2.0Vcc+5vP0.0P0.1P0.2P0.3P0.4P0.5P0.6VssGNDXTAL2P3.0/RXDRSTP3.1/TXDP3.2/INT0P3.3/INT1P3.4/T0P3.5/T1P3.6/WRP3.7/RDXTAL1P0.7Vpp/EAPROG/ALEPSENP0P2P3P1AlternatefunctionsCircuitofaPort3pin11101WriteCircuitofaPort3pin10010WriteCircuitofaPort3pin11101WriteCircuitofaPort3pin01110WriteCircuitofaPort3pin01ReadParallelportsonthe8051P0P1P3P2InputOutputLowaddressbyteDatabyte8031LatchEPROM

27512GND+5VGNDP0P1P3P2/EA/PSENALEA15A0D0A7/CECircuitofaPort0pin0+5V0Don’tforgetthatyouneedanexternalresistorforI/OCircuitofaPort0pin11011CircuitofaPort0pin10100CircuitofaPort0pinBothSinkandSourcecurrentscanbelargeforbusconnectionsParallelportsonthe8051P0P1P3P2InputOutputHighaddressbyte8031LatchEPROM

27512GND+5VGNDP0P1P3P2/EA/PSENALEA15A0D0A7/CECircuitofaPort2pinAnalogtoDigitalConversionAnaloginDigitaloutNlinesA-DconverterErrorsinA-DConversionVoltstimeAnalogueinDigitaloutVoltstimeErrorsinA-DConversion00000001000000100000001100000100Error误差VmaxNlines=2NstepsAnalogtoDigitalConversionAnaloginDigitaloutA-DconverterNlines%error80.4%100.1%160.0015%NlinesAccuracy转换精度=%errorPleasetry….Question8.6.6 Question8.6.7 (Page182)Question8.6.612linesWhatis%error?Question8.6.7Error<0.01%Numberoflines?SuccessiveApproximationConvertor逐次逼近式转换器+5V0VInputComparator3.8VToohighToolow2.53.754.37SwitchControlCircuit+5V0VInputSuccessiveApproximationConvertor逐次逼近式转换器ComparatorSwitchtree树状开关SwitchControlCircuitResistorladder电阻阶梯网络ADC0809Ch7D7Ch0D0OEEOCADDAADDCADDBMUXCompSuccessiveApproximationRegisterSwitchtreeResistorladderSTARTCLOCKREF+REF-IN7IN0ANALOGINDIGITALOUTALEADC0809Ch7D7Ch0D0OEEOCADDAADDCADDBMUXCompSuccessiveApproximationRegisterSwitchtreeResistorladderSTARTCLOCKREF+REF-IN7IN0ANALOGINDIGITALOUTALEMultiplexer多路调制器ADDCADDBADDACHANNEL000Ch0001Ch1010Ch2011Ch3100Ch4101Ch5110Ch6111Ch7ADC0809Ch7D7Ch0D0OEEOCADDAADDCADDBMUXCompSuccessiveApproximationRegisterSwitchtreeResistorladderSTARTCLOCKREF+REF-IN7IN0ANALOGINDIGITALOUTALESuccessiveApproximationConvertor逐次逼近式转换器InputComparatorREF+REF-ToolowSwitchControlCircuitADC0809Ch7D7Ch0D0OEEOCADDAADDCADDBMUXCompSuccessiveApproximationRegisterSwitchtreeResistorladderSTARTCLOCKREF+REF-IN7IN0ANALOGINDIGITALOUTALEConversiontime=100msEndofConversionADC0809to8051connections8051ADC08094:1dividerP1.0P1.1P1.2ALEALEADDAADDBADDCCLKSTARTOED7D0EOCP1.3P1.4P0.7P0.0INT0/P3.2VREF+VREF-IN7IN0ANALOGINSETB P1.3 ;StartconversionJB P3.2,$ ;WaitforEOCMOV A,P0+5GNDCh7Ch0BusywaitingUseinterruptADC0809to8051connections8051ADC08094:1dividerP1.0P1.1P1.2ALEALEADDAADDBADDCCLKSTARTOED7D0EOCP1.3P1.4P0.7P0.0INT0/P3.2VREF+VREF-IN7IN0ANALOGIN+5GNDCh7Ch0Example8.2.6.1Usingthiscircuit,writeaprogramtoputthenumberfromtheADCinto50hininternalRAM. UseADCChannel0 UseExternalInterrupt0

AJMP MAIN

ORG 0003h ;ISRforExtInt0

AJMP EOCINTMAIN:

MOV DPTR,#0000h

SETB P1.4 ;OutputenableOE

SETB IT0 ;Edgetriggering

SETB EA ;Enableinterrupts

SETB EX0

CLR P1.0 ;SetCh0asinput

CLR P1.1

CLR P1.2

SETB P1.3 ;Startconversion

SJMP $EOCINT:MOVX A,@DPTR

MOV 50h,A ;Resultin50h

RETIADC0809to8051connections8051ADC08094:1dividerP1.0P1.1P1.2ALEALEADDAADDBADDCCLKSTARTOED7D0EOCP1.3P1.4P0.7P0.0INT0/P3.2Vref+Vref-IN7IN0ANALOGIN+5GNDCh7Ch01567891011121432ReadingtheADC0809withMOVXP0P2NotconnectedDataD0-D7NotconnectedALE/RDADC0809to8051connections8051ADC08094:1dividerP1.0P1.1P1.2ALEALEADDAADDBADDCCLKSTARTOED7D0EOCP1.3P1.4P0.7P0.0INT0/P3.2Vref+Vref-IN7IN0ANALOGIN+5GNDCh7Ch0Example8.2.6.2ReadCh0(IN0)tolocation30hReadCh1(IN1)tolocation31hADC0809to8051connections8051ADC08094:1dividerP1.0P1.1P1.2ALEALEADDAADDBADDCCLKSTARTOED7D0EOCP1.3P1.4P0.7P0.0INT0/P3.2Vref+Vref-IN7IN0ANALOGIN+5GNDClock=12MHzALE=2MHzCLK=500kHzPleasetry…. Question8.6.9 Question8.6.10 Question8.6.11 Question8.6.12 Question8.6.13 (Page182)8.6.9 Howmanyanaloguechannels8-waymultiplexer.Thereare8channels8.6.10 WhatdoesOEpindo?OE=OutputEnable=sendsdigitaldataout8.6.11 WhatdoesEOCpindo?EOC=EndofConversion=outputready8.6.12 Howmanybitstoselectchannel8-waymultiplexer(0-7)requires3bits

8.6.13 WhatisthefunctionofREFpins?REFpinssettopandbottomofresistorladderADC0809Ch7D7Ch0D0OEEOCADDAADDCADDBMUXCompSuccessiveApproximationRegisterSwitchtreeResistorladderSTARTCLOCKREF+REF-IN7IN0ANALOGINDIGITALOUTALEDigitaltoAnalogConversionAnalogoutDigitalinNbitsD-AconverterR-2RResistorLadder+5V0VOutputRRRRRRR2R2R2R2R2R2RRfb010000011111MSBLSBSwitchControlCircuitDigitalinD0D7+-R-2RResistorLadder+5V0VOutputRRRRRRR2R2R2R2R2R2RRfb0MSBLSBSwitchControlCircuitD0D701001010010122N-142NVo+-DAC0832D7D0DIGITALINANALOGOUT/WR1/WR2/CS/XFERVREFIOUT1InputbufferRfbIOUT2RegisterILER-2RladderRfbInputLatchEnableR-2RResistorLadderVREF0VOutputRRRRRRR2R2R2R2R2R2RRfb010000011111MSBLSBIOUT1RfbSwitchControlCircuitD0D7DAC0832to8051connections8051D7P0.7ANALOGOUTD0/CS/XFER/WR1/WR2DAC0832RfbIOUT1IOUT2P0.0/WRP2.750h+-

ORG 0000h MOV

A,50h MOV

DPTR,#0000h ;MSB=0 MOVX @DPTR,A

;SenddatatoDAC SJMP $Toconvertdigitalvalueat50htoanalog…HowcanwecontroltwoDACSfromone8051?Example8.3.5(Page175)ReadP1andP3andoutputthevaluesastwoanalogvoltagesExample8.3.5Port3DAC=X01XXXXXXXXXXXXXPort1DAC=X10XXXXXXXXXXXXXStartDACs=0XXXXXXXXXXXXXXXBFFFhDFFFh7FFFh

ORG 0000hLOOP: MOV A,P1 ;PutP1intoA MOV DPTR,#0BFFFh;Clearbit14

MOVX @DPTR,A ;DatatoDAC2 MOV A,P3 ;PutP3intoA MOV DPTR,#0DFFFh;Clearbit13

MOVX @DPTR,A ;DatatoDAC1 MOV DPTR,#7FFFh ;Clearbit15 MOVX @DPTR,A ;OutputDACs SJMP LOOPExample8.3.5ReadP1andP3andoutputas twoanalogvoltagesPleasetry…. Question8.6.23 (Page183)Question8.6.23MOV A,P1 ;PutP1intoAMOV DPTR,#????h ;Clearbit14

MOVX @DPTR,A ;DatatoDAC2MOV A,P3 ;PutP3intoAMOV DPTR,#????h ;Clearbit13

MOVX @DPTR,A ;DatatoDAC1Example8.3.5Port3DAC=XXXXXX10XXXXXXXXPort1DAC=XXXXXX01XXXXXXXXFEFFhFDFFhQuestion8.6.23MOV A,P1 ;PutP1intoAMOV DPTR,#0FEFFh;Clearbit14

MOVX @DPTR,A ;DatatoDAC2MOV A,P3 ;PutP3intoAMOV DPTR,#0FDFFh;Clearbit13

MOVX @DPTR,A ;DatatoDAC1FEFFhFDFFhDallasSemiconductoriButton(DallasChip)iButton=IdentificationButtonSecurityguardsElectronickeysiButtonDimensions(inmm)Howmanybits?48bitsiButtonGNDSignalconnection(One-wire)iButtonConnectionsReaderPersonalIdentificationwithaniButtonIsanyonethere?Ithinksomeoneisthere!Whoareyou?Yes,I’mhereIamnumber56010110101ReaderMemoryPersonalIdentificationwithaniButton010101EachiButtonhasaunique48-bitcodeinROMHowmanydifferentnumbersarepossible?IDNumber(48bits)CRCCode(8bits)循环冗余码检验

ProductCode(8bits)LSBMSB64-bitROMcodeiButtonDimensions(inmm)ProductcodeCRCnumberDS1990AiButtoninternalcircuit64-bitROMInterfacelogicOne-wiretoReaderVs+5VGNDInitialisationProcedurePresencepulseResetpulseResistorReaderiButtonIsanyonethere?Yes,I’mhereWriteProceduresOneZeroSynchronisingedge10ReaderResistorWhoareyou?WriteProceduresOneZeroSynchronisingedge10ReaderResistorWhoareyou?ReadProcedureSynchronisingedge10ReadersamplingwindowIamnumber……UsingaMicrocontrollerastheReaderiButtonSocketLCDfordisplay+5VBus80518051P1.0(out)P1.1(in)RSRWED0D3BrightnessResistorPleasetry…. Question8.6.31 Question8.6.32 Question8.6.33 (Page184)8.6.31iButtonsourceofpowerFromtheone-wireconnectiontoacapacitor.8.6.32WhostartsthedialogueDialoguestartedbythereader-(low)8.6.33Componentsof64-bitnumberProductcode(8);IDnumber(48);CRC(8)ErrorCheckingMethodsParityBit -findsoddbiterrors -failsonpairsoferrors110100111000111110111000ErrorCheckingMethodsParityBit -findsoddbiterrors -failsonpairsoferrors2.Checksum -findsmosterrors -failsonswappedbits -failstofindmissingnulls110100111000111000111000ErrorCheckingMethodsParityBit -findsoddbiterrors -failsonpairsoferrors2.Checksum -findsmosterrors -failsonswappedbytes -failstofindmissingnulls3.