Clock configuration register
| SW | System clock switch |
| SWS | System clock switch status |
| HPRE | AHB prescaler |
| PPRE1 | APB low-speed prescaler (APB1) |
| PPRE2 | APB high-speed prescaler (APB2) |
| PLLSRC | PLL entry clock source |
| PLLMUL | PLL multiplication factor |
| PLLDIV | PLL output division |
| MCOSEL | Microcontroller clock output selection |
| MCOPRE | Microcontroller clock output prescaler |