Clock control register
| MSION | MSI clock enable |
| MSIRDY | MSI clock ready flag |
| MSIPLLEN | MSI clock PLL enable |
| MSIRGSEL | MSI clock range selection |
| MSIRANGE | MSI clock ranges |
| HSION | HSI clock enable |
| HSIKERON | HSI always enable for peripheral kernels |
| HSIRDY | HSI clock ready flag |
| HSIASFS | HSI automatic start from Stop |
| HSEON | HSE clock enable |
| HSERDY | HSE clock ready flag |
| HSEBYP | HSE crystal oscillator bypass |
| CSSON | Clock security system enable |
| PLLON | Main PLL enable |
| PLLRDY | Main PLL clock ready flag |
| PLLSAI1ON | SAI1 PLL enable |
| PLLSAI1RDY | SAI1 PLL clock ready flag |