form1.frm

通信控件MSComm的应用

VERSION 5.00
Object = "{648A5603-2C6E-101B-82B6-000000000014}#1.1#0"; "MSCOMM32.OCX"
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3090
   ClientLeft      =   60
   ClientTop       =   450
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3090
   ScaleWidth      =   4680
   StartUpPosition =   3  '窗口缺省
   Begin MSCommLib.MSComm MSComm1 
      Left            =   1920
      Top             =   120
      _ExtentX        =   1005
      _ExtentY        =   1005
      _Version        =   393216
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Public Sub InitCOM()
  On Local Error GoTo err1
  If MSComm1.PortOpen = True Then MSComm1.PortOpen = False
   MSComm1.CommPort = 1 '或其他口
   MSComm1.EOFEnable = False
   '由于和单片机通讯，只使用3根信号线，以下设置非常重要
   MSComm1.DTREnable = False
   MSComm1.Handshaking = comNone
   MSComm1.InBufferSize = 512
   '设置通讯数据大小为19个字节长
   MSComm1.InputLen = 19
   '设置通讯每19个字节长中断一次
   MSComm1.RThreshold = 19
   MSComm1.RTSEnable = False
   MSComm1.SThreshold = 0
   ' 9600 波特，无奇偶校验，8 位数据，一个停止位。
   MSComm1.Settings = "9600,N,8,1"
   '设定 InputMode 读取二进制数据
    MSComm1.InputMode = comInputModeBinary
   ' 当输入占用时，
   ' 告诉控件读入整个缓冲区。
   'MSComm1.InputLen = 0
   ' 打开端口。
   MSComm1.PortOpen = True
   COMPortOK = True
Exit Sub
err1:
    If Err.Source = "MSComm" Then
        'COMPortOK 为指示串口是否打开的全局变量
        COMPortOK = False
        MsgBox "串口不存在或连线未接", vbOKOnly + vbInformation
    End If
End Sub


Private Sub MSComm1_OnComm()
If MSComm1.CommEvent = comEvReceive Then
Text1.Text = AscB(MSComm1.Input)
            End If
MSComm1.InBufferCount = 0
End Sub