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IQ442Servicemanualpart2.pdf

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IQ442servicemanual CHAPTER6、CIRCUITINSTRUCTION 七、单元电路原理介绍 1 IQ442servicemanual CHAPTER7、UNITCIRCUITPRINCIPLEINTRODUCTION MT6577INTRODUCTION SystemOverview MT6577isahighlyintegratedbasebandplatformincorporatingbothmodemandapplication.processingsubsystemsto enable3G(UMTS)smartphoneapplications.Thechipintegratesa1GHzCortex-A9MCU,anARM1176MCUanda powerfulDSPprocessorwithmultimediacapabilities.TheMT6577interfacestoNANDflashmemory,32-bitmobile DDRandLPDDR2foroptimalperformanceandsupportsbootingfromNANDtominimizetheoverallBOMcost.In addition,anextensivesetofinterfacesandconnectivityperipheralsareincludedtointerfacetocameras,touch-screen displays,MMC/SDcardsandextemalBluetooth,WILANandGPSmodules. 7.1BasebandCPUcircuitintroductionforpowersupply Connectorfor powerchip CPUpower supplypart 2 IQ442servicemanual 7.2IntroductionforbasebandchipCPUpartcircuit Key communication Circuitforsensor interruptrequest 32.768KHZ CircuitSIMclockcircuit communication Communication Multi-media data transmission TPresetand Chargingdata data transmission transmission Tcarddata transmissionWIFIdata transmission 3 IQ442servicemanual Cameradata transmission Communica tioncontrol Camera interrupt control WCDMA receive I/Qsignal GSM、WCDMA sendI/Qsignal LCDdata transmission Audioconnector Bluetoothand audioconnector 4 IQ442servicemanual CHAPTER8、TROUBLESHOOTINGGUIDE 8.1Cannotswitchon Phoneconnectcurrent isabout50-100mAand cannotswitchon Updatesoftware NOYES NO Checkandreplace Checkpoweroutput： I/Oconnector CentresupplyVCCRE1.8V LogicalsupplyVDD2.8VNO NO AudiosupplyAVDD2.8V ClocksupplyVTCXO2.8VReplaceor MemorysupplyVMEM2.8Vre-solder RTCsupply:VRTC1.2Vthepower chip...... YES CheckandreplaceSYSClockYES 26MHZ32.768KHZ NO YES Replaceor re-soldermemory NO NO ReplaceU401MT6329AYES End 5 IQ442servicemanual