Real-time Clock (RTC)
The EM2000 features an onboard real-time clock (RTC). This RTC has a dedicated backup power input through pin VCCB of the module. Acceptable input voltage range for the VCCB pin is 1.8~3.3V.
You can connect the VCCB pin directly to the backup battery, just make sure that the voltage on VCCB line does not exceed 3.3V. You can also forget this line to the main 3.3V power.
Your Tibbo BASIC/C application can access the RTC through the RTC (rtc.) object, which is documented in the TIDE, TiOS, Tibbo BASIC, and Tibbo C Manual.