RTC initialization control and status register
| WUTWF | Wakeup timer write flag |
| SHPF | Shift operation pending |
| INITS | Initialization status flag |
| RSF | Registers synchronization flag |
| INITF | Initialization flag |
| INIT | Initialization mode |
| BIN | BIN |
| BCDU | BCDU |
| RECALPF | Recalibration pending Flag |