Intel MCS 51 User Manual

i~.
87C51GB HARDWAREDESCRIPTION
SerialExpansionPort Registers:The SerialExpansion channelsOthrough 7 respectively.The register ACMP
Port is controlled through the register SEPCON. contains the results of the A/D comparison feature.
SEPDATcontains data for the Serial ExpansionPort ACON is the control registerfor A/D conversions.
and SEPSTATis usedto monitorits status.
PowerControlR- PCONcontrolsthe PowerRe-
Interrupt Registers: The individual interrupt enable ductionModes,Idle and PowerDown.
bitsare in the IE and IEA registers.Oneoffour priori-
ty levelscan beselectedforeachinterrupt usingthe W, Oscillator Fail Detest Register:The OSCR registeris
IPH, IPA and IPAH registers.The EXICON register used both to monitor the status of the OPD circuitry
controlsthe selectionof the activationpolarity for ex-
and to disablethe feature.
temal interrupts two and three.
Watchdog Timer Register: The WatchDog Timer
Analos to Digital
Converter Resisters: The results of ReSeT(WDTRST)retister is used to keerrthe watch-
A/D ~nvers~ons are placed in-registers ADO,ADl,
dogtimer frompeno&ally resettingthe part.
AD2, AD3, AD4, AD5, AD6, and AD7 for analog
1
PortPin
Po.o/ADo-Po.7/AD7
P1.O/T2
P1.1/T2EX
P1.2/ECl
P1.3/CEXO
PI.41CEXI
P1.5/CEX2
P1.61CEX3
P1.7/CEX4
P2.O/A8-P2.71A15
P3.o/RxD
P3.1/TXD
P3.2/~
P3.3/m
P3.4fT0
P3.5/Tl
P3.6/~
P3.7/m
P4.OISEPCLK
P4.IASEPDAT
P4.2/ECll
P4.3/cl Exo
P4.4/cl Exl
P4.5/cl Ex2
P4.6/ClEX3
P4.71CIEX4
P5.2/lNT2
P5.3/lNT3
P5.4/lNT4
P5.5/lNT5
P5.6/lNT6
Me 3.AlternatePortFunotions
AlternateFunction
MultiplexedByteofAddreee/Dataforexternalmemow.
Timer2 ExternalClockinput/Clockout
Timer2 Reload/Capture/DirectionControl
PCAExternalClockInput
PCAModuleOCaptureInput,Compare/PWMOutput
PCAModule1CaptureInput,Compare/PWMOutput
PCAModule2CaptureInput,Compare/PWMOutput
PCAModule3CaptureInput,Compare/PWMOutput
PCAModule4CaDtureInr.wt.comDare/pWM(lttmt
HighByteofAddressforExternalMemcrry
SerialPortInput
SerialPortOutput
ExternalInterruptO
ExternalInterrupt1
17mer0ExternalClockInput
Timer1ExternalClockInput
WriteStrobeforExternalMemory
ReadStrobeforExternalMemory
ClockSourceforSEP
Date1/0forSEP
PCA1ExternalClockInput
PCA1ModuleO,CaptureInput,Compare/PWMOutput
PCA1Module1,CaptureInput,Compare/PWMOutput
PCA1Module2,CaptureInput,Compare/PWMOutput
PCA1Module3,CaptureInput,Compare/PWMOutput
PCAIModule4,CaptureInOut.
ChrIIDadF%’Vkf Outout
ExternalInterrupt2
ExternalInterrupt3
ExternalInterrupt4
Externalinterrupt5
ExternalInterrupt6
NOTE
Thealternatefunctionsc-anonlybeactivatedifthe correspondingbitIatehinthe IMrlSFRcontainsa 1.OtherwisetheDOrt
pinwillnotgohigh.
6-7

Intel MCS 51 Specifications

General

Brand	Intel
Model	MCS 51
Category	Microcontrollers
Language	English