25.3.2 Initialization
To initialize the TCD: 
   - Select the clock source and the prescaler from the Control A (TCDn.CTRLA) register.
 - Select the Waveform Generation mode from the Control B (TCDn.CTRLB) register.
 - Optional: Configure the other static registers to the desired functionality.
 - Write the initial values in the Compare (TCDn.CMPxSET/CLR) registers.
 - Optional: Write the desired values to the other double-buffered registers.
 - Ensure that the Enable Ready (ENRDY) bit in the Status (TCDn.STATUS) register is set
               to ‘
1’. -  Enable the TCD by writing a ‘
1’ to the ENABLE bit in the Control A (TCDn.CTRLA) register. 
