Thanks so much! I read many times that using 1.1v gives higher resolution but I thought the Arduino need such a pin which mine (nano) doesn't. I didn't realise it can be programmed in. This is really very helpful. Thanks again. 
Thanks so much! I read many times that using 1.1v gives higher resolution but I thought the Arduino need such a pin which mine (nano) doesn't. I didn't realise it can be programmed in. This is really very helpful. Thanks again.