25.3.3.2 Waveform Generation Modes

The TCF provides four waveform generation modes controlled by the Waveform Generation Mode (WGMODE) bit field in the Control B (TCFn.CTRLB) register. The waveform generation modes are:

Frequency generation
NCO Pulse-Frequency
NCO Fixed Duty Cycle
8-bit PWM

The registers functionality might be different for each mode and is summarized in the table below:

Table 25-4. Registers - Mode Differences
Mode	CNT2	CNT1	CNT0	CMP2	CMP1	CMP0	CMP1 Flag	CMP0 Flag	OVF Flag
Frequency Generation	Counter			Compare/TOP			CMP Match⁽¹⁾	CMP Match⁽¹⁾	TOP
NCO Pulse-Frequency	Counter/Accumulator			Increment			WO pulse end	WO pulse start	MAX
NCO Fixed Duty-Cycle	Counter/Accumulator			Increment			MAX⁽¹⁾	MAX⁽¹⁾	MAX
8-bit PWM	-	Period	Counter	-	Compare 1	Compare 0	CMP1 Match	CMP0 Match	TOP

Note:

CMP0 and CMP1 interrupts and events are generated on alternating overflows where one will match the rising edge of the waveform and the other the falling edge. An overflow interrupt/event is generated on all overflows.