Quote Originally Posted by Megahertz View Post
I have a RFmodule & a PIC (16F877A). They both can run upto 3V to 5V. One pin of the RF module gives a constant voltage of 2.8V.

I plan to run the PIC on 4 AA batteries, rechargeable. (appx 1.2v - 1.3v when fully charged).

I want to take this lower voltage (2.8V) as a reference and check when battery pack reaches 3.6. Can someone please guide me how I can take the lower voltage as a ref and check the supply voltage. Thanks
I didn't check the Data Sheet for the 16F877A to see whether it has an HLVD module or not. If it does, you can easily use the technique I described in an article on this forum to check the supply voltage. Check it out at: http://www.picbasic.co.uk/forum/cont...oltage-monitor . It has schematic, layout, code, et al. Hope this helps.