Dear Andy,
Will you please modify the message for attamting to reprogramme dbl clock bit for 89V51?.
We can read the dbl clock bit and if it is already in 6 clock mode, either display successful or say it is already in 6 clock mode.
If some attemps to clear the dbl clk bit, we can display it is not allowed. Why to give error?.
-Harshadbhai