APB1 peripheral clock enable register 1
| TIM2EN | CPU1 TIM2 timer clock enable |
| RTCAPBEN | CPU1 RTC APB clock enable |
| WWDGEN | CPU1 Window watchdog clock enable |
| SPI2S2EN | CPU1 SPI2S2 clock enable |
| USART2EN | CPU1 USART2 clock enable |
| I2C1EN | CPU1 I2C1 clocks enable |
| I2C2EN | CPU1 I2C2 clocks enable |
| I2C3EN | CPU1 I2C3 clocks enable |
| DAC1EN | CPU1 DAC1 clock enable |
| LPTIM1EN | CPU1 Low power timer 1 clocks enable |