【精品】串口分析

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1、串口驱动分析（国嵌）1.发送和接收发送：循环buffer发送fifoT发送移位寄存器接收：接收移位寄存器T接收fifoTFIip_buf发送的过程是：把数据写到发送fifo中，fifo把收到的数据传给发送移位寄存器（自动的，非driver控制），然后每个时钟脉冲往串口线上写一bit数据。接收的过程是：接收移位寄存器收到数据，发送给接收fifo,接收fifo事先设置好了触发门限,当里面的数据量超过门限时就会触发一个中断，调用驱动中的中断处理函数，把数据写到flip_buf中。1.寄存器ULCONnBitDescriptionInitialS

2、tateReswvodFl0Infra-RedModeNDeterminewhetherornottousetheInfra-Redmode.0二Normalmodeoperation1=Infra-RedTx/Rxmode0ParityMode[5:3]SpecifylhetypeofpantygenerahonandcheckingdunngUARTtransmitandoperation.Oxx=Noparity100=Oddparity101=Evenparity110=Parityforced^checkedas1111-Par

3、ityforced^dieckedas0000NumberofStopBitR1Specifyhowmanystopbitsaretobeusedforendof-framesignal.0=Onestopbitporframe1=Twostopbitperframe0WordLength㈣Indicatethenumberofdatabitstobetransmittedorreceivedperframe.00=5*bits01-6-bits10-7-bit$11-8-bits00WordLength:数据位长度NumberofSto

4、pBit:停止位数ParityMode:奇偶校验位类型Infra-RedMode:UART/红外模式选择(当以UART模式工作时，需UCONnBitDescriptionInitialStateClockSelectionHO]SelectPCLKorUCLKfortheUARTbaudrale.O^PCLK:UBRDIVn=仲l)(PCLK/(bpsx16))-11=UCLK(@GPH8):UBRDIVn=(inQ(UCLK/(bpsx16))-10TxIntemiplType(91Intemjptrequesttype.0=Pulse

5、(IntemjptisrequestedassoonastheTxbufferb&comosemptyinNon-FIFOmodeorreachesTxFIFOTriggerLevelinFIFOmode.)1匸Level(IntemjptisrequestedwhileTxbufferisemptyinNon-FIFOmodeocreachesTxFIFOTriggerLevelinFIFOmode.)0RxInterruptType

6、6

7、Intemjptrequesttype.0=Pulse(IntemjptisrequestedIh

8、oinstantRxbufferrocoivosthedatainNonFIFOmodeorreachesRxFIFOTriggerLevelinFIFOmode.)1二Level(Intomjptisrequesl^dwhileRxbufferisreceivingdatainNon-FIFOmodeorreachesRxFIFOTriggerLevelinFIFOmode.)0RxTmeOutEnableFlEnable/OisableRxtimeoutinterruptwhenUARTFIFOisenabled.Theinterru

9、pttsareceiveinterrupt.0=Disable1=Enable0RxErrorStatusInterruptEnable

10、6

11、EnabletheUARTtogenerateaninterruptuponanexception,suchasabreak,frameerror,parityerror,oroverrunerrorduringareceiveoperation.0=Donotgeneratereceiveerrorstatusinterrupt1二Generatereceiveerrorstatusmtemjpt

12、.0LoopbackMode(5]Settingloopbackbitto1causestheUARTtoentertheloopbackmode.Thismodetsprovidedfort