20.3.3.4.5 Port Override for Waveform Generation
To make the waveform generation available
         on the port pins, the corresponding port pin direction must be set as output (PORTx.DIR[n]
         = 1). The TCA will override the port pin values when the compare channel
         is enabled (CMPnEN = 1 in the TCAn.CTRLB register), and a Waveform
         Generation mode is selected.
The figure below shows the port override
         for TCA. The timer/counter compare channel will override the port pin output value
         (PORTx.OUT) on the corresponding port pin. Enabling inverted I/O on the port pin (INVEN =
            1 in the PORTx.PINnCTRL register) inverts the corresponding WG
         output.
