FT245BM中文资料

DS245BVersion1.6©FutureTechnologyDevicesIntl.Ltd.2005Page1of24FT245BMUSBFIFO(USB-Parallel)I.C.TheFT245BMisthe2ndgenerationofFTDI’spopularUSBFIFOI.C.ThisdevicenotonlyaddsextrafunctionalitytoitsFT8U245AMpredecessorandreducesexternalcomponentcount,butalsomaintainsahighdegreeofpincompatibilitywiththeoriginal,makingiteasytoupgradeorcostreduceexistingdesignsaswellasincreasingthepotentialforusingthedeviceinnewapplicationareas.1.0FeaturesHARDWAREFEATURES•SingleChipUSBParallelFIFObi-directionalDataTransfer•TransferDatarateto1MByte/Sec-D2XXDrivers•TransferDatarateto300Kilobyte/Sec-VCPDrivers•SimpletointerfacetoMCU/PLD/FPGAlogicwitha4wirehandshakeinterface•EntireUSBprotocolhandledon-chip…noUSB-specificfirmwareprogrammingrequired•FTDI’sroyalty-freeVCPandD2XXdriverseliminatetherequirementforUSBdriverdevelopmentinmostcases.•384ByteFIFOTxbuffer/128ByteFIFORxBufferforhighdatathroughput.•NewSendImmediatesupportviaSIPinforoptimiseddatathroughput.•SupportforUSBSuspend/ResumethroughPWREN#andWAKEUPpins.•SupportforhighpowerUSBBuspowereddevicesthroughPWREN#pin•AdjustableRXbuffertimeout•In-builtsupportforeventcharacters•IntegratedlevelconverteronFIFOandcontrolsignalsforinterfacingto5Vand3.3Vlogic•Integrated3.3VregulatorforUSBIO•IntegratedPower-On-Resetcircuit•Integrated6MHz–48MhzclockmultiplierPLL•USBBulkorIsochronousdatatransfermodes•NewBit-BangModeallowsthedatabustobeusedasan8bitgeneralpurposeIOPortwithouttheneedforMCUorothersupportlogic.•4.35Vto5.25Vsinglesupplyoperation•UHCI/OHCI/EHCIhostcontrollercompatible•USB1.1andUSB2.0compatible•USBVID,PID,SerialNumberandProductDescriptionstringsinexternalEEPROM•EEPROMprogrammableon-boardviaUSB•Compact32LDLQFPpackageVIRTUALCOMPORT(VCP)DRIVERSfor-Windows98andWindows98SE-Windows2000/ME/XP-WindowsCE4.2-MACOS-8andOS-9-MACOS-X-Linux2.40andgreaterD2XX(USBDirectDrivers+DLLS/WInterface)-Windows98andWindows98SE-Windows2000/ME/XP-WindowsCE4.2-Linux2.4andGreaterAPPLICATIONAREAS-EasyMCU/PLD/FPGAinterfacetoUSB-UpgradingLegacyPeripheralDesignstoUSB-USBInstrumentation-USBIndustrialControl-USBAudioandLowBandwidthVideodatatransfer-PDAUSBdatatransfer-USBMP3PlayerInterface-USBFLASHCardReader/Writers-SetTopBox(S.T.B.)PC-USBinterface-USBDigitalCameraInterface-USBHardwareModems-USBWirelessModemsDS245BVersion1.6©FutureTechnologyDevicesIntl.Ltd.2005Page2of24FT245BMUSBFIFO(USB-Parallel)I.C.2.0EnhancementsThissectionsummarisestheenhancementsofthe2ndgenerationdevicecomparedtoitsFT8U245AMpredecessor.Forfurtherdetails,consultthedevicepin-outdescriptionandfunctionaldescriptions.•IntegratedPower-On-Reset(POR)CircuitThedevicenowincorporatesaninternalPORfunction.TheexistingRESET#pinismaintainedinordertoallowexternallogictoresetthedevicewhererequired,howeverformanyapplicationsthispincannowbeeitherleftN/CorhardwiredtoVCC.Inaddition,anewresetoutputpin(RSTOUT#)isprovidedinordertoallowthenewPORcircuittoprovideastableresettoexternalMCUandotherdevices.RSTOUT#wastheTESTpinonthepreviousgenerationofdevices.•IntegratedRCCLKCircuitInthepreviousdevices,anexternalRCcircuitwasrequiredtoensurethattheoscillatorandclockmultiplierPLLfrequencywasstablepriortoenablingtheclockinternaltothedevice.Thiscircuitisnowembeddedon-chip–thepinassignedtothisfunctionisnowdesignatedastheTESTpinandshouldbetiedtoGNDfornormaloperation.•IntegratedLevelConverteronFIFOinterfaceandcontrolsignalsThepreviousdeviceswoulddrivetheFIFOandcontrolsignalsat5VCMOSlogiclevels.ThenewdevicehasaseparateVCCIOpinallowingthedevicetodirectlyinterfaceto3.3VandotherlogicfamilieswithouttheneedforexternallevelconverterI.C.’s•PowerManagementcontrolforUSBBusPowered,highcurrentdevices1.1GeneralDescriptionTheFT245BMprovidesaneasycost-effectivemethodoftransferringdatato/fromaperipheralandahostP.C.atupto8Millionbits(1Megabyte)persecond.Itssimple,FIFO-likedesignmakesiteasytointerfacetoanymicrocontrollerormicroprocessorviaIOports.Tosenddatafromtheperipheraltothehostcomputer,simplywritethebyte-widedataintothemodulewhenTXE#islow.Ifthe(384-byte)transmitbufferfillsuporisbusystoringthepreviouslywrittenbyte,thedevicekeepsTXE#highinordertostopfurtherdatafrombeingwrittenuntilsomeoftheFIFOdatahasbeentransferredoverUSBtothehost.TXE#goeshighaftereverybytewritten.WhenthehostsendsdatatotheperipheraloverUSB,thedevicewilltakeRXF#lowtolettheperipheralknowthatatleastonebyteofdataisavailable.TheperipheralcanreadadatabyteeverytimeRXF#goeslow.RXF#goeshighaftereverybyteread.ByusingFTDI’svirtualCOMportdrivers,theperipherallookslikeastandardCOMporttotheapplicationsoftware.Commandstosetthebaudrateareignored-thedevicealwaystransfersdataatitsfastestrateregardlessoftheapplication’sbaud-ratesetting.Alternatively,FTDI’sD2XXdriversallowapplicationsoftwaretoaccessthedevice“directly”throughapublishedDLLbasedAPI.DetailsofthecurrentVCPandD2XXdrivercanbefoundonFTDI’swebsite()DS245BVersion1.6©FutureTechnologyDevicesIntl.Ltd.2005Page3of24FT245BMUSBFIFO(USB-Parallel)I.C.AnewPWREN#signalisprovidedwhichcanbeusedtodirectlydriveatransistororP-ChannelMOSFETinapplicationswherepowerswitchingofexternalcircuitryisre