VB串口发送接收

发布网友发布时间：2023-07-16 01:40

我来回答

共3个回答

热心网友时间：2024-08-23 13:43

LZ的代码错在：

Dim send(4) As Byte

它定义的Byte数组有5个元素，所以单片机不返回数据。应该改为：

Private Sub Command1_Click() '发送HEX数据93 93 93 93

Dim send(3) As Byte

send(0) = "&H93"

send(1) = "&H93"

send(2) = "&H93"

send(3) = "&H93"

MSComm1.Output = send

End Sub

这样才发送4字节指令，此外从MSComm1.RThreshold = 34看是设置接收字节长度为34字节。

以下修改了LZde1代码，供参考：

Option Explicit
    Dim strdata
Private Sub Command1_Click() '发送HEX数据93 93 93 93
    Dim send(3) As Byte
    send(0) = "&H93"
    send(1) = "&H93"
    send(2) = "&H93"
    send(3) = "&H93"
    MSComm1.Output = send
End Sub

Private Sub Form_Load()
    '串口初始化
    MSComm1.Settings = "9600,n,8,1"
    MSComm1.InputLen = 0
    MSComm1.InputMode = comInputModeBinary
    MSComm1.InBufferSize = 1024
    MSComm1.OutBufferSize = 512
    MSComm1.RThreshold = 34 '设置接收字节长度
    MSComm1.InBufferCount = 0
    MSComm1.OutBufferCount = 0
    MSComm1.CommPort = 1 '串口号
    MSComm1.PortOpen = True
    Timer1.Interval = 0
End Sub

Private Sub MSComm1_OnComm()
    Dim i As Long
    Dim strBuff As String
    Dim strdata As String
    Dim str() As Byte
    Select Case MSComm1.CommEvent
        Case comEvReceive
        strBuff = MSComm1.Input
        str() = strBuff
        For i = 0 To UBound(str)    '接收16进制数据
        If Len(Hex(str(i))) = 1 Then
            strdata = strdata & "0" & Hex(str(i))
        Else
            strdata = strdata & Hex(str(i))
        End If
        Next
        Text1.Text = strdata
        Call Timer1_Timer
    End Select
End Sub

Private Sub Timer1_Timer()
    strdata = ""
    MSComm1.InBufferCount = 0
End Sub

热心网友时间：2024-08-23 13:43

修改这里。。。

Private Sub MSComm1_OnComm()
Dim strBuff As String
Dim strdata As String
Dim str() As Byte

Select Case MSComm1.CommEvent
Case comEvReceive
strBuff = MSComm1.Input
str() = strBuf
在这里添加接收字符长度的判断，长度够了再接收。处理。。
For i = 0 To UBound(str) '接收16进制数据
If Len(Hex(str(i))) = 1 Then
strdata = strdata & "0" & Hex(str(i))
Else
strdata = strdata & Hex(str(i))
End If
Next

热心网友时间：2024-08-23 13:44

你简单的个通讯给你写的这么复杂。
你直接发送output
然后等待50ms最少
直接input就OK了。