'*************************************************************************************
'初始化串口返回=-1 无效！
Public Function Init_Comm(com_id As String) As Integer
    nCid = OpenComm(com_id, 512, 512) '′打开COM2 设置接收,发送缓冲区为512 字节
   
    If nCid < 0 Then
        Init_Comm = -1 '′处理错误
    Else
        Init_Comm = cCid
    End If
   
End Function
'*********************************************************************************
Public Function Build_Comm(com_Info As String) As Integer
    Dim comset As String
    Dim err As Integer
   
    err = 0
    comset = com_Info + "  ,n ,8 ,1" '"COM2 :9600 ,n ,8 ,1"
    If (BuildCommDCB(comset, LpDCB)) Then err = -1 ' 无法创建
   
    LpDCB.Id = Chr(nCid)
   
    If (SetCommState(LpDCB)) Then err = -2 ' 无法创建′设置串口状态
    Build_Comm = err
   
End Function
'**************************************************************************
'发送数据
Public Function Send_Data_Out_Comm(p As String, cnt As Integer) As Integer

    Dim nsend As Integer, x As Integer
   
    Dim Lpstate As COMSTAT '通信状态块
   
    x = GetCommError(nCid, Lpstate)  '′读取当前串口错误或状态
   
    If Lpstate.cbOutQue < 512 Then  '′送缓冲区有空间否?
   
        nsend = WriteComm(nCid, p, cnt)   '′发送inbuff
   
        If nsend <= 0 Then nsend = -nsend  ' '′忽略错误
  
    End If
   
    Send_Data_Out_Comm = cnt
End Function
'**************************************************************************
'读取数据
Public Function Read_Data_Out_Comm(p() As String) As Integer

    Dim nsend As Integer, x As Integer
   
    Dim Lpstate As COMSTAT '通信状态块
   
        
   
    x = GetCommError(nCid, Lpstate)  '′读取当前串口错误或状态
   
    If Lpstate.cbInQue < 512 Then  '′缓冲区有空间否?
   
        nsend = ReadComm(nCid, p, cnt)   '′发送inbuff
   
        If nsend <= 0 Then nsend = -nsend  ' '′忽略错误
  
    End If
   
    Read_Data_Out_Comm = Lpstate.cbInQue
End Function

'***********************************************************************************
'关闭串口，释放资源
Public Function Close_Comm()
    Dim Nclose As Integer
   
    Nclose = Closecomm(nCid)
   
    nCid = 0
   
End Function