22.3.3.1.8 8-Bit PWM Mode
The TCB can be configured to run in 8-bit PWM mode, where each of the register pairs in the 16-bit Compare/Capture (TCBn.CCMPH and TCBn.CCMPL) register are used as individual Compare registers. The period (T) is controlled by CCMPL, while CCMPH controls the duty cycle of the waveform. The counter will continuously count from BOTTOM to CCMPL, and the output will be set at BOTTOM and cleared when the counter reaches CCMPH.
CCMPH is the number of cycles for which the output will be driven high. CCMPL+1 is the period of the output pulse.