简单串口通信测试程序,哪位高手能帮小弟我看看为何不能接收数据,只能发射

简单串口通信测试程序,谁能帮我看看为何不能接收数据,只能发射
问题如题,希望各位多指点,现在孤军作战,身边无可交流之人.
另外,本人也没有什么VB基础,烦请各位耐心指教,让我先通信起来,先谢过了.

Private Sub Command2_Click()
mscomm_init
MSComm1.Output = Chr(Val(Text1.Text))
MSComm1.PortOpen = False
End Sub

Private Sub Option1_Click()
mscomm_init
MSComm1.Output = Chr(&H33)
MSComm1.PortOpen = False

End Sub

Private Sub Option2_Click()
mscomm_init
MSComm1.Output = Chr(&H66)
MSComm1.PortOpen = False
End Sub

Private Sub mscomm_init()
MSComm1.CommPort = 2
If MSComm1.PortOpen = False Then
  With MSComm1
  .CommPort = 2
   
  .RThreshold = 1 ' 设置触发oncom事件的字节数
  .SThreshold = 0
  .Settings = "56000,n,8,1"
  .InputMode = comInputModeBinary
  .PortOpen = True
  .InBufferCount = 0 '清空缓存
  .OutBufferCount = 0
  .InputLen = 1
   
   
  End With

Else
MSComm1.PortOpen = False
MsgBox ("串口已开启,无法使用")
End If
End Sub
Private Sub Picture1_Click()
Line (0, 9)-(0, 3000)
End Sub
Private Sub MSComm1_OnComm()
Dim a As Byte
Select Case MSComm1.CommEvent
Case comEvReceive
  a = MSComm1.Input
   
End Select


End Sub
Private Sub Form_Load()
  MSComm1.CommPort = 2
  MSComm1.RThreshold = 1
  If MSComm1.PortOpen = True Then
  MSComm1.PortOpen = False
  End If
  Rem MSComm1.PortOpen = True
End Sub


Private Sub 发送数据_Click()

End Sub


[解决办法]
发送时打开COM口后你把COM关闭了,无法接收.MSCOMM控件的属性设置,仅可能用其缺省设置.

VB code

Option Explicit    Dim strData As StringPrivate Sub Command2_Click()    MSComm1.Output = Chr(Val(Text1.Text))End SubPrivate Sub Option1_Click()    MSComm1.Output = Chr(&H33)End SubPrivate Sub Option2_Click()    MSComm1.Output = Chr(&H66)End SubPrivate Sub mscomm_init()    MSComm1.CommPort = 1End SubPrivate Sub Picture1_Click()    Line (0, 9)-(0, 3000)End SubPrivate Sub MSComm1_OnComm()    Dim a() As Byte    Dim i As Integer    Select Case MSComm1.CommEvent        Case comEvReceive        a = MSComm1.Input        For i = 0 To UBound(a)        If Len(Hex(a(i))) = 1 Then            strData = strData & "0" & Hex(a(i))        Else            strData = strData & Hex(a(i))        End If        Next        '以下写符合通信协议规定的判断代码处理接收数据        Text2.Text = strData     End SelectEnd SubPrivate Sub Form_Load()    MSComm1.CommPort = 1    MSComm1.RThreshold = 1    If MSComm1.PortOpen = False Then        With MSComm1            .CommPort = 1            .RThreshold = 1    ' 设置触发oncom事件的字节数              .Settings = "56000,n,8,1"            .InputMode = comInputModeBinary '2进制接收              .PortOpen = True            .InBufferCount = 0    '清空缓存              .OutBufferCount = 0            .InputLen = 0        End With    Else        MSComm1.PortOpen = False        MsgBox ("串口已开启,无法使用")    End IfEnd Sub
[解决办法]
首先 你的问题不属于 COM/DCOM/COM+ 这类
你的程序中 打开串口后 发送数据 然后马上就关闭了这个串口当然接收不到了  
还有就是 也没有接收事件啊
Private Sub MSComm1_OnComm() '接收数据
   Dim BytReceived() As Byte
   Dim strBuff As String
   Select Case MSComm1.CommEvent
       Case 2
           MSComm1.InputLen = 0
           strBuff = MSComm1.Input
           BytReceived() = strBuff
。。。。。。
  这样 就对了