Help with PIC18LF4455 low voltage

[Jaromit]

Hi:
I'm trying to use PIC18LF4455 with a clock battery of 3V. I'm gonna use it with USB, but im trying a program that only ligths 1 led, but doesnt work. The same circuit and program works just fine with a 5V battery and I don't now why. Do I need to configure something for it to work with low voltage? Please, help

[absalom]

According datasheet you need at least 3V for HSPLL, XTPLL, ECPIO and ECPLL Oscillator modes. Have you measured the battery voltage during operation?
btw: Are you aware that the USB Module with On-Chip Transceiver has a current consumption of 8..14mA? Maybe it is cheaper to use the USB voltage from the host to supply your device.

[Jaromit]

The battery gives 3.3V, I've checked. I can't use the USB voltage because the circuit won't be connected all the time to the PC. What I don't understand is why a program that only lights a LED don't work with clock battery.

[absalom]

Please check the brown out voltage, maybe a reset is triggered by BOR