请大家帮我看看串口接收程序吧！总是校验的时候容易掉数据！抓狂了！
我用的波特率为57600采样的周期为10ms，
程序如下：
Public Event MyOnComm()
Public cSetting As String
Public nPortNum As Long
Public b收到一组 As Boolean
Public b收发完成 As Boolean
Public aInputstr As Variant
Public n等待时间 As Long
Public a参数 As Variant
Public b数据错误 As Boolean
Public b通信正常 As Boolean
Public b保存记录 As Boolean
Public nRecNum As Long '收发的数据计数
Public nLastRecTime As Long
Public n命令字 As Byte
Public nC51等待时间 As Long
Dim aRecStr(1999) As String '收发的数据
Dim ch() As Byte
Dim ch_z(2000) As Byte
Dim ch_m(16) As Byte
Dim cCode() As Byte
Dim chData() As Byte
Dim chi As Long
Dim oBz As PictureBox
Dim ch_n As Long
Dim ch_i As Long
Dim m, y As Integer
Dim WithEvents oC51 As MSComm
Private Sub oC51_OnComm()
Dim Buffer As Variant
Dim k As Long
Dim lni As Long
Dim nPlc_Rec_Len As Long
' Select Case
' Case comEvReceive
Buffer = oC51.Input
If UBound(Buffer) < 900 And chi < 8096 Then
ch = Buffer
For k = LBound(Buffer) To UBound(Buffer)
ch_z(chi) = ch(k)
chi = chi + 1
Next k
frmMain.Text7.Text = CStr(chi)
y = y + 1
frmMain.Text8.Text = CStr(y)
If chi > 6 Then
Call p收到数据检查
End If
If chi = 1 Then
b收到一组 = True
n等待时间 = 0
b通信正常 = True
b数据错误 = False
ReDim chData(0) As Byte
chData(0) = ch_z(0)
chi = 0
aInputstr = chData
RaiseEvent MyOnComm
End If
Else
chi = 0
End If
'
' Case comEvSend
' ' 错误
' Case comEventBreak ' 收到 Break。
' Case comEventCDTO ' CD (RLSD) 超时。
' Case comEventCTSTO ' CTS Timeout。
' Case comEventDSRTO ' DSR Timeout。
' Case comEventFrame ' Framing Error
' Case comEventOverrun '数据丢失。
' MsgBox "与串口通信时，数据丢失！", vbInformation, App.Title
' Case comEventRxOver '接收缓冲区溢出。
' MsgBox "与串口通信时，接收缓冲区溢出！", vbInformation, App.Title
' Case comEventRxParity ' Parity 错误。
' Case comEventTxFull '传输缓冲区已满。
' Case comEventDCB '获取 DCB] 时意外错误
'
' ' 事件
' Case comEvCD ' CD 线状态变化。
' Case comEvCTS ' CTS 线状态变化。
' Case comEvDSR ' DSR 线状态变化。
' Case comEvRing ' Ring Indicator 变化。
' Case comEvEOF ' 输入数据流中发现 EOF 字符
' End Select
End Sub
Private Sub p收到数据检查()
Dim lni As Long
Dim k As Long
Dim CRC As Long
Dim i As Long
If chi = 16 Then
ch_n = 1
Do While ch_n <= chi - 2 And Not (ch_z(ch_n) = &HCC And ch_z(ch_n + 1) = &H33 And ch_z(ch_n + 2) = &HC3)
ch_n = ch_n + 1
DoEvents
Loop
If ch_n < chi - 2 Then '收到一个帧结尾
If ch_z(0) <> &HAA Then '不是一个完整的帧开头
' lni = 1
' Do While ch_z(lni) <> &HAA And lni <= chi - 2
' lni = lni + 1
' Loop
' If ch_z(lni) = &HAA Then
' For k = lni To chi
' ch_z(k - lni) = ch_z(k)
' Next k
' chi = chi - lni
' End If
End If
If ch_z(0) = &HAA Then '是一个完整的帧
' lni = 1
' Do While ch_z(lni) <> &HAA And lni < ch_n - 2
' lni = lni + 1
' Loop
' If ch_z(lni) = &HAA Then
' For k = lni To chi
' ch_z(k - lni) = ch_z(k)
' Next k
' chi = chi - lni
' ch_n = ch_n - lni
' End If
CRC = 0
For lni = 1 To ch_n - 3 '算出校验和
CRC = CRC + ch_z(lni)
Next lni
ReDim chData(ch_n) As Byte
If CRC Mod 256 = ch_z(ch_n - 1) Then '数据完整 校验和正确
For lni = 0 To ch_n
chData(lni) = ch_z(lni)
Next lni
aInputstr = chData
m = m + 1
frmMain.Text4.Text = CStr(m)
chi = chi - ch_n - 3
If chi > 0 Then
chi = 0
' For lni = 0 To chi
' ch_z(lni) = ch_z(lni + ch_n + 2)
' Next lni
End If
b收到一组 = True
n等待时间 = 0
b通信正常 = True
b数据错误 = False
nLastRecTime = GetTickCount
DoEvents
RaiseEvent MyOnComm
Else
For lni = 0 To ch_n
chData(lni) = 5
Next lni
aInputstr = chData
chi = chi - ch_n - 3
If chi > 0 Then
chi = 0
' For lni = 0 To chi
' ch_z(lni) = ch_z(lni + ch_n + 2)
' Next lni
End If
b收到一组 = True
n等待时间 = 0
b通信正常 = True
b数据错误 = False
nLastRecTime = GetTickCount
RaiseEvent MyOnComm
End If
Else
chi = 0 '放弃该帧
End If
End If
ElseIf chi = 32 Then
ch_n = 16
Do While ch_n <= chi - 2 And Not (ch_z(ch_n) = &HCC And ch_z(ch_n + 1) = &H33 And ch_z(ch_n + 2) = &HC3)
ch_n = ch_n + 1
DoEvents
Loop
If ch_n < chi - 2 Then '收到一个帧结尾
If ch_z(ch_n - 13) <> &HAA Then '不是一个完整的帧开头
' lni = 1
' Do While ch_z(lni) <> &HAA And lni <= chi - 2
' lni = lni + 1
' Loop
' If ch_z(lni) = &HAA Then
' For k = lni To chi
' ch_z(k - lni) = ch_z(k)
' Next k
' chi = chi - lni
' End If
End If
If ch_z(ch_n - 13) = &HAA Then '是一个完整的帧
CRC = 0
For lni = 17 To chi - 6 '算出校验和
CRC = CRC + ch_z(lni)
Next lni
ReDim chData(ch_n - 14) As Byte
If CRC Mod 256 = ch_z(chi - 4) Then '数据完整 校验和正确
For lni = 0 To 15
chData(lni) = ch_z(lni + 16)
Next lni
aInputstr = chData
chi = chi - ch_n - 3
If chi > 0 Then
chi = 0
' For lni = 0 To chi
' ch_z(lni) = ch_z(lni + ch_n + 2)
' Next lni
End If
b收到一组 = True
n等待时间 = 0
b通信正常 = True
b数据错误 = False
nLastRecTime = GetTickCount
DoEvents
RaiseEvent MyOnComm
Else
For lni = 17 To ch_n - 6
chData(lni) = 5
Next lni
aInputstr = chData
chi = chi - ch_n - 3
If chi > 0 Then
chi = 0
' For lni = 0 To chi
' ch_z(lni) = ch_z(lni + ch_n + 2)
' Next lni
End If
b收到一组 = True
n等待时间 = 0
b通信正常 = True
b数据错误 = False
nLastRecTime = GetTickCount
RaiseEvent MyOnComm
End If
Else
chi = 0 '放弃该帧
End If
End If
End If
End Sub
现在的现象是10000个数据，递增方式传输给我，就是说1,2,3,4,5,6……，9998,9999,10000
但是传输的数据到数组Data(10000)中时,Data的值总是有跳动的数字，比如Data（1）=2，Data（3）=5，为什么？
