用VB调试串口通讯

sp; ''判断是否为数据的开始标志

                    .RThreshold = 0   ''关闭OnComm事件接收

                End If

                Do

                    DoEvents

                Loop Until .InBufferCount >= 3  ''循环等待接收缓冲区>=3个字节

''                nRece = nRece + 1

                For i = 2 To 12

                    SwichVar i

                    Text1.Text = Text1.Text & Chr(Out(i))

                Next

                Text1.Text = LTrim(Text1.Text)

                Text2.Text = Text2.Text & CStr(nRece)

                .RThreshold = 1  ''打开MSComm事件接收

            Case Else

''                .PortOpen = False

        End Select

    End With

End Sub

****************************************************************************

Private Sub DelayTime()

    Dim bDT As Boolean

    Dim sPrevious As Single, sLast As Single

    

    bDT = True

    sPrevious = Timer  (Timer可以计算从子夜到现在所经过的秒数，在Microsoft Windows中，Timer函数可以返回一秒的小数部分)

    Do While bDT

        If Timer - sPrevious >= 0.3 Then bDT = False

    Loop

    bDT = True

End Sub

（通信传输速率为9600bps，则最快速度1.04ms发送一个字节，仪表每秒发送50帧数据，每帧数据有4个字节，即每秒发送200个字节，平均5.0ms 发送一个字节，连续读取串口数据时要在程序中添加循环等待程序）

Private Sub SwichVar(ByVal nNum As Integer)

    DelayTime

    var = Null

    var = MSC.Input

    Out(