RCC APB4 Clock Register
| SYSCFGEN | SYSCFG peripheral clock enable |
| LPUART1EN | LPUART1 Peripheral Clocks Enable |
| SPI6EN | SPI6 Peripheral Clocks Enable |
| I2C4EN | I2C4 Peripheral Clocks Enable |
| LPTIM2EN | LPTIM2 Peripheral Clocks Enable |
| LPTIM3EN | LPTIM3 Peripheral Clocks Enable |
| LPTIM4EN | LPTIM4 Peripheral Clocks Enable |
| LPTIM5EN | LPTIM5 Peripheral Clocks Enable |
| COMP12EN | COMP1/2 peripheral clock enable |
| VREFEN | VREF peripheral clock enable |
| RTCAPBEN | RTC APB Clock Enable |
| SAI4EN | SAI4 Peripheral Clocks Enable |
| DTSEN | Digital temperature sensor peripheral clock enable Set and reset by software. |