xs128芯片微控制器IO.ppt

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1、FreescaleHCS12微控制器-I/OPortIntegrationModule•输入/输出功能选择(PortsT,S,M,P,H,J)•降低功耗•使能和上/下拉极性•中断使能和相应的状态寄存器标准IO具有以下基本功能:•输入输出位选择•2种可选输出驱动能力•输入上/下拉选择其它功能:•开路线或功能(PortsS,M)•中断输入信号滤波(PortsP,H,J)中断信号上/下沿A.B.E.K工作在扩展模式下，可做总线信号；H.J.M.S.P.T工作在端口集成模块方式下输入寄存器可用来检测输出管脚的短路，过载HCS12具有丰富的I/O资源和多种功能模块，因封装和管脚限

2、制，引脚大都为功能复用，通过设置相应寄存器可实现如下功能，PortIntegrationModuleInput/OutputDrivecurrent:OutputHigh:全功率:12.5mAatVdd-.8V降功率:1.25mAatVdd-.8VOutputLow:全功率:-12.5mAat.8V降功率:-1.25mAat.8VLogicThresholds:High:0.65XVdd=3,25VLow:0.35XVdd=1,75V上/下拉电阻:上/下拉使能极性选择寄存器控制上/下拉，电流大概100uA线或:S和M具有线或功能ModuleRoutingRegister

3、:其目的是在最小尺寸和最少模块下，为HCS12提供尽可能多的功能。PIM-ReroutingT端口AddressOffset$0000Areadreturnslatchedvaluewhenconfiguredforoutputorvalueattheinputpinwhenwhenconfiguredasinput.PPT-PortTI/OReg.DDRT-PortTDirectionReg.PTIT-PortTInputRegisterRDRT-PortTReducedDriveReg.PERT-PortTPullDeviceEnableReg.PPST-PortT

4、PolaritySelectReg.$0002DDRTx=0PinisInput=1PinisOutput$0001ContainscurrentpinstatusThisregistermaybeusedtodetectoverloadorshortcircuitconditionontheoutputpin$0003RDRTx=0Pinoutputfulldrive=1Pinoutput1/3drive$0004PERTx0=Pull-up/downdisabled1=Pull-up/downenabled$0005PPSTx0=PortTpinxhaspull-u

5、p1=PortTpinxhaspull-downPPS-PortSI/OReg.DDRS-PortSDirectionReg.PTIS-PortSInputReg.RDRS-PortSReducedDriveReg.PERS-PortSPullDeviceEnableReg.PPSS-PortSPolaritySelectReg.WOMS-PortSWired-OrReg.AddressOffset$0008Areadreturnslatchedvaluewhenconfiguredforoutputorvalueattheinputpinwhenwhenconfigu

6、redasinput.$000ADDRSx=0PinisInput=1PinisOutput$0009Containscurrentpinstatus$000BRDRSx=0Pinoutputfulldrive=1Pinoutput1/3drive$000CPERSx0=Pull-up/downdisabled1=Pull-up/downenabled$000DPPSSx0=PortSpinxhaspull-up1=PortSpinxhaspull-down$000EPPSSx0=Push-pulloutput1=Open-drainoutputS端口M端口PPS-Po

7、rtMI/OReg.DDRM-PortMDirectionReg.PTIM-PortMInputReg.RDRM-PortMReducedDriveReg.PERM-PortMPullDeviceEnableReg.PPSM-PortMPolaritySelectReg.WOMM-PortMWired-OrReg.AddressOffset$0010Areadreturnslatchedvaluewhenconfiguredforoutputorvalueattheinputpinwhenwhenconfiguredasinput.$00