AHB2 peripheral clock enable register
| GPIOAEN | IO port A clock enable |
| GPIOBEN | IO port B clock enable |
| GPIOCEN | IO port C clock enable |
| GPIODEN | IO port D clock enable |
| GPIOEEN | IO port E clock enable |
| GPIOHEN | IO port H clock enable |
| ADCEN | ADC clock enable |
| AES1EN | AES1 accelerator clock enable |