Mettre en majuscule automatiquement une saisie excel

Sub CommandButton1()
For Each maj In [a2:b100] 'plage a traitée
Application.ScreenUpdating = False
If maj <> "" Then
maj.Select
maj = UCase(maj)
ActiveCell = maj
End If
Next
Application.ScreenUpdating = True
Range("a1").Select
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
Dim Cel As Range
Dim Plg As Range
Set Plg = Intersect(Target, [a1:b1000])
If Plg Is Nothing Then Exit Sub
For Each Cel In Plg
    Cel = UCase(Cel)
Next Cel
End Sub