I am trying to determine the suitable set-up to determine when my system's battery source (lipo battery) is too depleted. I am running my nrf52 at 3 volts and the Lipo Battery @ 4.2 volts fully charged with a 3.7 volts nominal.
I don't want to connect the battery directly to a gpio/adc because the voltage is out of the operating range.
I also don't want to put a resistor voltage divider because it would constantly drain the battery. Too big of resistors would create a high impedance and lead to error in the saadc. Too small would lead to a constant battery drain. Connecting the bottom of a resistor voltage divider to a gpio and, switching from disconnected (floating) to connected and driven low would cause the both gpio pins to exhibit voltages above the operating ranges during the disconnected setting.
I believe I'm over thinking all of this... Your help would be appreciated. Thanks.
