Jordan,
If the maximum voltage measured by your 5V sourced PSoC is 4V or less, you can directly measure the battery voltage across the + and - terminals. Although I would highly recommend at least a 1K series resistance in each terminal being measured.
If your PSoC is 3.3V, you would probably need a voltage divider to scale down the voltage to about 0.6V lower than the supply to the PSoC.
Len
Len
"Engineering is an Art. The Art of Compromise."
