Control/status register (RCC_CSR)
| LSION | Internal low speed oscillator enable |
| LSIRDY | Internal low speed oscillator ready |
| RMVF | Remove reset flag |
| OBLRSTF | Option byte loader 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 |
| LPWRRSTF | Low-power reset flag |