3.3.2 If RTC is not Used
CVDDRTC AND LDOI MUST always be supplied even if RTC is not used
LDOI supplies power to the internal LDOs, the bandgap reference generator circuits, and serve as the I/O supply for some input pins
CVDDRTC MUST NOT be supplied by any on-chip LDO output
If the RTC oscillator is not used, it can be disabled by connecting RTC_XI to CVDDRTC and RTC_XO to ground (or left floating). CVDDRTC must be supplied with a voltage within the recommended operating conditions.
NOTE
When RTC oscillator is disabled, the RTC registers (I/O address range 1900h – 197Fh) are not accessible.