CTRLA

Control A

  0x00 8 PAC Write-Protection 0x00  

Control A

Bit  7 6 5 4 3 2 1 0  
            CKSEL      
Access            R/W      
Reset            0      

Bit 2 – CKSEL: Main Clock Select

Main Clock Select

ValueDescription
0 The GCLKMAIN clock is selected for the main clock.
1 The DFLLULP clock is selected for the main clock.