Control/status register
| LSION | Internal low-speed oscillator enable |
| LSIRDY | Internal low-speed oscillator ready |
| LSEON | External low-speed oscillator enable |
| LSERDY | External low-speed oscillator ready |
| LSEBYP | External low-speed oscillator bypass |
| LSECSSON | CSS on LSE enable |
| LSECSSD | CSS on LSE failure Detection |
| RTCSEL | RTC and LCD clock source selection |
| RTCEN | RTC clock enable |
| RTCRST | RTC software reset |
| RMVF | Remove reset flag |
| OBLRSTF | Options bytes loading reset flag |
| PINRSTF | PIN reset flag |
| PORRSTF | POR/PDR reset flag |
| SFTRSTF | Software reset flag |
| IWDGRSTF | Independent watchdog reset flag |
| WWDGRSTF | Window watchdog reset flag |
| LPWRSTF | Low-power reset flag |