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SHT30温湿度传感器部分翻译资料3PinAssignment3、引脚分配TheSHT3x-DIScomesinatiny8-pinDFNpackageseeTable6.SHT3x-DIS是一个8位的DFN小包，见表63.1PowerPins(VDD,VSS)3.1、电源引脚（VDD,VSS）TheelectricalspecificationsoftheSHT3x-DISareshowninTable3.Thepowersupplypinsmustbedecoupledwitha100nFcapacitorthatshallbeplacedasclosetothesensoraspossible–seeFigure11foratypicalapplicationcircuit.SHT3x-DIS的电气参数如表3所示。电源引脚必须与一个100nF的电容器尽可能地隔离，以便尽可能靠近传感器——请参见典型应用电路图11。3.2SerialClockandSerialData(SCL,SDA)3.2、串行时钟和串行数据（SCL，SDA）SCLisusedtosynchronizethecommunicationbetweenmicrocontrollerandthesensor.Theclockfrequencycanbefreelychosenbetween0to1000kHz.CommandswithclockstretchingaccordingtoI2CStandard11aresupported.SCL用于同步微控制器和传感器之间的通信。时钟频率可以在0到1000千赫之间自由选择。支持按I2C标准11进行时钟扩展的命令。TheSDApinisusedtotransferdatatoandfromthesensor.Communicationwithfrequenciesupto400kHzmustmeettheI2CFastMode11standard.Communicationfrequenciesupto1MhzaresupportedfollowingthespecificationsgiveninTable20.SDA引脚用于向传感器传递数据和从传感器传递数据。频率高达400kHz的通信必须满足I2C快速模式11标准。根据表20给出的规格，支持1兆赫的通信频率。BothSCLandSDAlinesareopen-drainI/OswithdiodestoVDDandVSS.Theyshouldbeconnectedtoexternalpull-upresistors(pleaserefertoFigure11).AdeviceontheI2Cbusmustonlydrivealinetoground.Theexternalpull-upresistors(e.g.Rp=10kΩ)arerequiredtopullthesignalhigh.Fordimensioningresistorsizespleasetakebuscapacityandcommunicationfrequencyintoaccount(seeforexampleSection7.1ofNXPsI2CManualformoredetails11).Itshouldbenotedthatpull-upresistorsmaybeincludedinI/Ocircuitsofmicrocontrollers.ItisrecommendedtowirethesensoraccordingtotheapplicationcircuitasshowninFigure11.SCL和SDA线均为开路漏极，有二极管连到VDD和VSS。它们应该与外部上拉电阻相连接（请参见图11）。I2C总线上的设备必须只有一条线接地。外部上拉电阻（如Rp=10kΩ）需要高的信号。关于尺寸标注的电阻，请将线路容量和通信频率考虑在内（更多细节请参见NXPs12C手册第7.1节）。需要注意的是，在微控制器的I/O电路中可以包括上拉电阻。建议根据图11应用电路连接传感器。3.3DiePad(centerpad)3.3、模具衬垫或中心衬垫Thediepadorcenterpadisvisiblefrombelowandlocatedinthecenterofthepackage.ItiselectricallyconnectedtoVSS.Henceelectricalconsiderationsdonotimposeconstraintsonthewiringofthediepad.However,duetomechanicalreasonsitisrecommendedtosolderthecenterpadtothePCB.Formoreinformationondesign-in,pleaserefertothedocument“SHTxxDesignGuide”.从下面可见位于小包中心的模具衬垫或中心衬垫。它与VSS相连。因此，电气方面的考虑不会对接线板接线造成限制。然而，由于机械原因，建议将焊盘焊到PCB。关于设计中更多的信息，请参阅文档“SHTxx设计指南”。3.4ADDRPin3.4、ADDR引脚ThroughtheappropriatewiringoftheADDRpintheI2Caddresscanbeselected(seeTable7fortherespectiveaddresses).TheADDRpincaneitherbeconnectedtoVDDorVSS,oritcanbeusedasaselectorpin.ThismeansthattheaddressofthesensorcanbechangeddynamicallyduringoperationbyswitchingthelevelontheADDRpin.TheonlyconstraintisthatthelevelhastostayconstantstartingfromtheI2Cstartconditionuntilthecommunicationisfinished.ThisallowstoconnectmorethantwoSHT3x-DISontothesamebus.ThedynamicalswitchingrequiresindividualADDRlinestothesensors.通过ADDR引脚合适的接线，可以选择I2C地址（见表7中的相应地址）。ADDR引脚可以直接连接到VDD或VSS，或者也可以作为一个选择销。这意味着传感器的地址可以改变，在运行过程中动态切换水平上的地址引脚。唯一的限制是电平必须保持恒定，从I2C开始状态直到通信结束。这允许将超过两sht3xDIS连接在同一总线。动态切换要求单个地址线传感器。PleasenotethattheI2Caddressisrepresentedthroughthe7MSBsoftheI2Creadorwriteheader.TheLSBswitchesbetweenreadorwriteheader.ThewiringforthedefaultaddressisshowninTable7andFigure11.TheADDRpinmustnotbeleftfloating.Pleasenotethatonlythe7MSBsoftheI2CRead/WriteheaderconstitutetheI2CAddress.请注意，I2C地址是通过I2C读写头的7位表达出来的。LSB在读写头之间切换。默认地址的接线如表7和图11所示。addr引脚不能悬空。请注意，只有I2C读写头的7位构成了I2C地址。3.5ALERTPin3.5、警报引脚Thealertpinmaybeusedtoconnecttotheinterruptpinofamicrocontroller.TheoutputofthepindependsonthevalueoftheRH/Treadingrelativetoprogrammablelimits.Itsfunctionisexplainedinaseparateapplicationnote.Ifnotused,thispinmustbeleftfloating.Thepinswitcheshigh,whenalertconditionsaremet.ThemaximumdrivingloadsarelistedinTable3.Beawarethatself-heatingmightoccur,dependingontheamountofcurrentthatflows.Self-heatingcanbepreventediftheAlertPinisonlyusedtoswitchatransistor.警报引脚可用于连接微控制器的中断引脚。引脚的输出取决于相对于可编程限制的RH/T读数的值。它的功能会在单独的应用说明中解释。如果不使用，该引脚必须悬空。当警报状态满足时，引脚开关调高。最大驱动载荷列于表3中。请注意，可能会发生自加热，这取决于流过的电流量。如果警报引脚仅用于开关晶体管，则可以防止自加热。3.6nRESETPin3.6、NRESET引脚ThenResetpinmaybeusedtogeneratearesetofthesensor.Aminimumpulsedurationof1µsisrequiredtoreliablytriggeraresetofthesensor.Itsfunctionisexplainedinmoredetailinsection4.Ifnotuseditisrecommendedtoleavethepinfloating.NRESET引脚可用于传感器复位。至少1µ的脉冲持续时间需要可靠地触发传感器重置。第4节对其功能作了更详细的解释。如果不使用，建议让引脚悬空。4OperationandCommunication4、操作和通信TheSHT3x-DISsupportsI2Cfastmode(andfrequenciesupto1000kHz).Clockstretchingcanbeenabledanddisabledthroughtheappropriateusercommand.FordetailedinformationontheI2Cprotocol,refertoNXPI2C-busspecification12.SHT3x-DISs支持I2C快速模式（频率高达1000kHz）。可以通过适当的用户命令启用或禁用时钟扩展。关于I2C协议的详细信息，参见NXPI2C总线规范12。AllSHT3x-DIScommandsanddataaremappedtoa16-bitaddressspace.Additionally,dataandcommandsareprotectedwithaCRCchecksum.Thisincreasescommunicationreliability.The16bitscommandstothesensoralreadyincludea3bitCRCchecksum.Datasentfromandreceivedbythesensorisalwayssucceededbyan8bitCRC.所有SHT3x-DIS的命令和数据映射到16位地址空间。此外，数据和命令用CRC校验和进行保护。这增加了通信的可靠性。传感器的16位命令已经包含一个3位CRC校验和。传感器发送和接收的数据总是由8位CRC校验成功。Inwritedirectionitismandatorytotransmitthechecksum,sincetheSHT3x-DISonlyacceptsdataifitisfollowedbytheco