Even though the low-voltage detection control register (LVDCR) has been set, low voltage detection is not occurring at the intended voltage. Are there any other registers that need to be set?
Has 3Ch been set to the key code register for low-voltage detection control register (LVDKEYR) before writing to the LVDCR register? Writing of the LVDCR register is enabled/disabled by the LVDKEYR register. Write 3Ch to the LVDKEYR register and read LVDKEYR once, and then write to LVDCR.