Data Sheet

FSC‐BT646Datasheet
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 ShenzhenFeasycomTechnologyCo.,Ltd   www.feasycom.com
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30 P2.0/I2C1_SDA I/O Programmableinput/outputline
AlternativeFunction:I2CDATAline(Default) 
Note
1,3
31 P0.3 I/O Programmableinput/outputline 
AlternativeFunction1:AnalogueprogrammableI/Oline.
AlternativeFunction2:HostMCUdisconnectbluetooth
Note1
32 P0.2 I/O Programmableinput/outputline
AlternativeFunction:LED(Default)
Note
1,4
33 P0.7 I/O Programmableinput/outputline
AlternativeFunction:BTStatus(Default)
Note
1,2
34 P5.2/EXT_WAKEUP I/O Programmableinput/outputline 
35 GND Vss RFGround 
36 EXT_ANT O RFsignaloutput Note5
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ModulePinNotes:
Note1 Forcustomizedmodule,thispincanbeworkasI/OInterface.
Note2 BTStatus(Default)‐‐Disconnected:LowLevel;Connected:HighLevel.
Note3
I2CSerialClockandData.
Itisessentialtorememberthatpull‐upresistorsonbothSCLandSDAlinesarenotprovidedinthemodule
andMUSTbeprovidedexternaltothemodule.
Note4 LED(Default)‐‐PowerOn:LightSlowShinning;Connected:SteadyLighting.
Note5
Bydefault,thisPINisanemptyfeet.ThisPINcanconnecttoanexternalantennatoimprovetheBluetooth
signalcoverage.
Ifyouneedtouseanexternalantenna,bymodifyingthemoduleonthe0Rresistancetoblockoutthe
on‐boardantenna;OrcontactFeasycomformodification.
Note6 ThisI/OportissharedwiththeinternalSPIFlashchip.Wedonotrecommendusingthispin,floating
processing.
Thispinisonlyavailablewhenthemoduleisnotequippedwithair‐upgradefunction.
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4.  PHYSICALINTERFACE
 4.1  PowerSupply
Thetransientresponse oftheregulator isimportant.Ifthe powerrailsof themodulearesupplied fromanexternal
voltagesource,thetransientresponseofanyregulatorusedshouldbe20μsorless.Itisessentialthatthepowerrail
recoversquickly.
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4.2Reset
Themodulemayberesetfromseveralsources:Power‐onReset(POR),LowlevelonthenRESETPin(nRST),Watchdog
time‐outreset(WDT),Lowvoltagereset(LVR).
TheRESETpinisanactivelowresetandisinternallyfilteredusingtheinternallowfrequencyclockoscillator.Aresetwill
beperformedbetween1.5and4.0msfollowingRESETbeingactive.ItisrecommendedthatRESETbeappliedforaperiod
greaterthan5ms.