Clock configuration register
| SW | System clock switch |
| SWS | System clock switch status |
| HPRE | AHB prescaler |
| PPRE1 | PB low-speed prescaler (APB1) |
| PPRE2 | APB high-speed prescaler (APB2) |
| STOPWUCK | Wakeup from Stop and CSS backup clock selection |
| HPREF | AHB prescaler flag |
| PPRE1F | APB1 prescaler flag |
| PPRE2F | APB2 prescaler flag |
| MCOSEL | Microcontroller clock output |
| MCOPRE | Microcontroller clock output prescaler |