form1.frm

在发一个PC机与51单片机通讯的程序

VERSION 5.00
Object = "{648A5603-2C6E-101B-82B6-000000000014}#1.1#0"; "MSCOMM32.OCX"
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3285
   ClientLeft      =   7725
   ClientTop       =   5715
   ClientWidth     =   5865
   LinkTopic       =   "Form1"
   ScaleHeight     =   3285
   ScaleWidth      =   5865
   Begin VB.CommandButton Command2 
      Caption         =   "清除"
      Height          =   375
      Left            =   120
      TabIndex        =   5
      Top             =   1680
      Width           =   495
   End
   Begin VB.TextBox Text2 
      Appearance      =   0  'Flat
      Height          =   1695
      Left            =   720
      MultiLine       =   -1  'True
      ScrollBars      =   2  'Vertical
      TabIndex        =   4
      Top             =   1080
      Width           =   4815
   End
   Begin MSCommLib.MSComm MSComm1 
      Left            =   0
      Top             =   2280
      _ExtentX        =   1005
      _ExtentY        =   1005
      _Version        =   393216
      DTREnable       =   0   'False
      InBufferSize    =   1
      InputLen        =   1
      OutBufferSize   =   1
      RThreshold      =   1
      BaudRate        =   4800
      SThreshold      =   1
      InputMode       =   1
   End
   Begin VB.TextBox Text1 
      Appearance      =   0  'Flat
      Height          =   270
      Left            =   1560
      MaxLength       =   2
      TabIndex        =   1
      Text            =   "ff"
      Top             =   480
      Width           =   375
   End
   Begin VB.CommandButton Command1 
      Caption         =   "发送"
      Height          =   375
      Left            =   2160
      TabIndex        =   0
      Top             =   480
      Width           =   1095
   End
   Begin VB.Label Label2 
      Caption         =   "接收:"
      Height          =   255
      Left            =   120
      TabIndex        =   3
      Top             =   1080
      Width           =   615
   End
   Begin VB.Label Label1 
      Caption         =   "发送(十六进制):"
      Height          =   255
      Left            =   120
      TabIndex        =   2
      Top             =   480
      Width           =   1575
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False

Private Sub Command1_Click() '点击按钮1(发送按钮)触发

Dim aaa(0) As Byte '定义一个字节型一维数组aaa,
aaa(0) = "&h" + Text1.Text '组合16进制以便发送
MSComm1.OutBufferCount = 0 '清空输出寄存器
MSComm1.Output = aaa '发送

End Sub


Private Sub Command2_Click() '点击按钮2(清屏)时触发
Text2.Text = "" '清屏
End Sub

Private Sub Form_Load() '加载窗体时触发

MSComm1.CommPort = 1 '用Com1口
MSComm1.Settings = "4800,n,8,1" '通讯参数 波特率 奇偶校验 数据位 停止位
MSComm1.PortOpen = True '开串口

End Sub



Private Sub MSComm1_OnComm() '有数据传送时触发

Select Case MSComm1.CommEvent 'CommEvent属性：返回最近的通讯事件或错误。通过对它具体属性值的查询，我们就可以获得通讯事件和通 讯错误的完整信息。当其值是comEvReceive时表示接收到数据。
Case comEvReceive '有接收事件



Dim a As Variant '定义1个可变类型
Dim b(0) As Byte '字节数组

a = MSComm1.Input '接收到的数据存放到a里
b(0) = AscB(a) ' 返回a的值  asc()返回字符串第一个字母的值


Text2.Text = Text2.Text & " " & Hex(b(0)) '组合显示&   并且转换成16进制hex()

MSComm1.InBufferCount = 0 '...清空输入寄存器

End Select

End Sub