A.40ΩB.60ΩC.70ΩD.50Ω
A.電源沒打開B.電源打開且正常C.正在發(fā)送數(shù)據(jù)D.未發(fā)送數(shù)據(jù)
A.串口1/2正在接受數(shù)據(jù)B.未發(fā)送數(shù)據(jù)C.串口1/2正在發(fā)送數(shù)據(jù)D.未接收數(shù)據(jù)