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1、ChipSTC12C5204ADI/OportconfigurationSTC12C5204ADseriesmicrocontrolleritsallI/Oportsarecontrolledbythesoftwareconfigurationinto4kindsofworktype4typesarerespectively:quasitwo-waymouth(standardthe8051outputmode),push-pulloutput,onlyforinput(highresistance)oropen-drainoutputfunctions.Every
2、mouthconsistsoftwocontrolregistertherelevantpositioncontroleachpintypeofwork.STC12C5204ADseriesmicrocontrollertoelectricityreattachmentshallprevailtwo-waymouth(standardthe8051outputmode)mode:2Vabovehighlevel,0.8Vforlowlevelbelow.1.Quasitwo-waymouthoutputconfigurationQuasitwo-waymouthou
3、tputtypecanbeusedasoutputandinputfunctionbutdon'tneedtoreconfiguremouthlinesoutputstate.Thisisbecausejuncturelinesoutputis1driveabilityisveryweak,allowingexternaldeviceswillitsdown.Whenpinsforlow,itoutputdrivingability,canabsorbtheconsiderablecurrent.Quasitwo-waymouthhave3pull_uptransi
4、storadaptedtodifferentneeds.Inthethreeandonetransistor,pulluptransistorcalledweakonpull",for1andpaternallineregistersitselfpinsfor1open.Thispull_upprovidesbasicdrivecurrentmakeprospectivetwo-waymouthfor1output.Ifapinfor1andoutputbyexternaldevicestodropdowntolow,pullupcloseandweak"veryw
5、eakpull_up"maintainopenposition,inordertoputthispinforlow,strongtopulltheexternaldevicesmusthaveenoughpowertomakepininfusedcurrentthresholdvoltageofavoltagetothefollowing.Article2pull_uptransistors,called"extremelyweakonpull",1latchpaternallinewhenopen.Whenpin,theveryweaksuspendedthepu
6、ll_upsourcegeneratesveryweakandcurrentwillpinandhighlevel.Article3pull_uptransistorcalled"powerfulpull".Juncturelinelatchesfrom0to1,thejumpingtoacceleratemustpullupbylogic0totwo-waymouthlogic1conversion.Whenthishappened,powerfulpullopenabout2machinecycletomakepinscanquicklypulltotheear
7、thhighlevel.Quasitwo-waymouthoutputshownbelow.STC12C520seriesmicrocontroller3Vdevice,iftheuserisinpinsplus5Vvoltage,therewillbeacurrentflowfrompins,thishascausedadditionalVDDpowerconsumption.Accordingly,theproposalisnotinquasitwo-waymouthmode3Vmicrocontrollerpinstoexert5Vvoltage,such