Peripherals independent clock configuration register
| USART1SEL | USART1 clock source selection |
| USART2SEL | USART2 clock source selection |
| SPI2S2SEL | SPI2S2 I2S clock source selection |
| LPUART1SEL | LPUART1 clock source selection |
| I2C1SEL | I2C1 clock source selection |
| I2C2SEL | I2C2 clock source selection |
| I2C3SEL | I2C3 clock source selection |
| LPTIM1SEL | Low power timer 1 clock source selection |
| LPTIM2SEL | Low power timer 2 clock source selection |
| LPTIM3SEL | Low power timer 3 clock source selection |
| ADCSEL | ADC clock source selection |
| RNGSEL | RNG clock source selection |