41.6.2.1 Initialization
The following registers are enable-protected, meaning that they can only be written when the ADC is disabled (CTRLA.ENABLE=0):
- Control B register (CTRLB)
 - Reference Control register (REFCTRL)
 - Event Control register (EVCTRL)
 - Calibration register (CALIB)
 
Enable-protection is denoted by the "Enable-Protected" property in the register description.
