split the string into 12-character substrings then insert into database. plz help

Private Sub SMSPort_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles comPort.DataReceived
 
Dim str As String = ""
Dim temp As String = ""
 
objCon.GetConnectionString()
If e.EventType = SerialData.Chars Then
 
SMSPort.DtrEnable = True
System.Threading.Thread.Sleep(100)
tempp = SMSPort.ReadExisting().Replace("", "").Trim()
 
//' iwant to add here split function to split more than 12 charcters into only 12 character then give entry into database..
 
'For i As Integer = 1 To tempp.Length Step 12
' Debug.Write(Mid(tempp, i, 12))
 
If tempp <> "" Then
objCon.GetConnectionString()
objCon.GetConnection("Insert into tblAttended(Id,Status,Date,Time)values('" + tempp.ToString() + "','In','" + System.DateTime.Today.ToShortDateString() + "','" + DateTime.Now.ToShortTimeString() + "')")
 
ListView1.Items.Add(tempp)
txtUniqueNumber.Text = tempp.Trim()
ListView1.AutoResizeColumns(ColumnHeaderAutoResizeStyle.ColumnContent)
End If
'Next i
 
Control.CheckForIllegalCrossThreadCalls = False
  
End Sub