APB peripheral clock enable register 2
| SYSCFGEN | SYSCFG, COMP and VREFBUF clock enable |
| TIM1EN | TIM1 timer clock enable |
| SPI1EN | SPI1 clock enable |
| USART1EN | USART1 clock enable |
| TIM14EN | TIM14 timer clock enable |
| TIM16EN | TIM16 timer clock enable |
| TIM17EN | TIM16 timer clock enable |
| ADCEN | ADC clock enable |