I've powered a no-bootloader 328 and 168 from two and three AA batteries. I believe the Arduino fuse settings enable the Brown Out Detector for just over 4 volts. You may not be able to use 3.3V unless you can change the fuses.
I've powered a no-bootloader 328 and 168 from two and three AA batteries. I believe the Arduino fuse settings enable the Brown Out Detector for just over 4 volts. You may not be able to use 3.3V unless you can change the fuses.