Quote Originally Posted by Charles Linquis View Post
If you set Vref to Vdd and read the A/D, you will find that the constant 2.8V will give you an A/D count of LARGER than 716 when the battery voltage drops below 4V. No resistors needed.
Since it is a battery powered application. This seems a better option. Could you please explain more. I not an expert on this subject.