By default, the TCB is in Periodic Interrupt mode. Follow these steps to start using it:
  1. 1.Write a TOP value to the Compare/Capture (TCBn.CCMP) register.
  2. 2.Optional: Write the Compare/Capture Output Enable (CCMPEN) bit in the Control B (TCBn.CTRLB) register to ‘1’. This will make the waveform output available on the corresponding pin, overriding the value in the corresponding PORT output register.
  3. 3.Enable the counter by writing a ‘1’ to the ENABLE bit in the Control A (TCBn.CTRLA) register.

    The counter will start counting clock ticks according to the prescaler setting in the Clock Select (CLKSEL) bit field in the Control A (TCBn.CTRLA) register.

  4. 4.The counter value can be read from the Count (TCBn.CNT) register. The peripheral will generate a CAPT interrupt and event when the CNT value reaches TOP.
    1. a.If the Compare/Capture register is modified to a value lower than the current CNT, the peripheral will count to MAX and wrap around.
    2. b.At MAX, an OVF interrupt and event will be generated.