45.6.2.5.8 Output Polarity

The polarity (WAVE.POLx) is available in all waveform output generation. In single-slope and dual-slope PWM operation, it is possible to invert the pulse edge alignment individually on start or end of a PWM cycle for each compare channels. The table below shows the waveform output set/clear conditions, depending on the settings of timer/counter, direction, and polarity.

Table 45-4. Waveform Generation Set/Clear Conditions
Waveform Generation Operation DIR POLx Waveform Generation Output Update
Set Clear
Single-Slope PWM 0 0 Timer/counter matches TOP Timer/counter matches CCx
1 Timer/counter matches CC Timer/counter matches TOP
1 0 Timer/counter matches CC Timer/counter matches ZERO
1 Timer/counter matches ZERO Timer/counter matches CC
Dual-Slope PWM x 0 Timer/counter matches CC when counting up Timer/counter matches CC when counting down
1 Timer/counter matches CC when counting down Timer/counter matches CC when counting up

In Normal and Match Frequency, the WAVE.POLx value represents the initial state of the waveform output.