BRuTuS:
I wonder if it's an issue with the Energizer Lithium batteries or the Minty Boost. I've run Rayovac Hybrid (nickel metal hydride) batteries completely dead in the SparkFun converter without problems.
Are you sure that there is such a thing as PULLDOWN built into the standard arduino boards?
There is not a PULLDOWN resistor built in; it's a PULLUP resistor. I mentioned the PULLDOWN resistor because I vaguely remember that an external pulldown resistor was recommended in the datasheet for a certain situation. I wanted Vortexnl to know what options are available.
The point is that floating pins are a potential power drain. I've tested configuring unused pins as INPUTS w/ INTERNAL PULLUPS and OUTPUTS set LOW. There wasn't any measureable difference between the two. But there was a big difference when the pins are configured as simple inputs (the default setting).
- Brian