118
ATmega16M1/32M1/64M1 [DATASHEET]
8209E–AVR–11/2012
Table 15-3 shows the COMnx1:0 bit functionality when the WGMn3:0 bits are set to the fast PWM mode.
Note:
1. A special case occurs when OCRnA/OCRnB equals TOP and COMnA1/COMnB1 is set. In this case the compare
Table 15-4 shows the COMnx1:0 bit functionality when the WGMn3:0 bits are set to the phase correct or the phase
and frequency correct, PWM mode.
Note:
1. A special case occurs when OCRnA/OCRnB equals TOP and COMnA1/COMnB1 is set. See
“Phase correct PWM Bit 1:0 – WGMn1:0: Waveform Generating mode
Combined with the WGMn3:2 bits found in the TCCRnB Register, these bits control the counting sequence of the
counter, the source for maximum (TOP) counter value, and what type of waveform generating to be used, see
Clear Timer on Compare match (CTC) mode, and three types of Pulse Width Modulation (PWM) modes.
See “16-Table 15-3.
Compare Output mode, fast PWM
COMnA1/COMnB1
COMnA0/COMnB0
Description
0
Normal port operation, OCnA/OCnB disconnected
01
WGMn3:0 = 14 or 15: Toggle OC1A on Compare
Match, OC1B disconnected (normal port operation).
For all other WGM1 settings, normal port operation,
OC1A/OC1B disconnected
10
Clear OCnA/OCnB on Compare Match, set
OCnA/OCnB at TOP
11
Set OCnA/OCnB on Compare Match, clear
OCnA/OCnB at TOP
Table 15-4.
Compare Output mode, phase correct and phase and frequency correct PWM
COMnA1/COMnB1
COMnA0/COMnB0
Description
0
Normal port operation, OCnA/OCnB disconnected
01
WGMn3:0 = 8, 9 10 or 11: Toggle OCnA on Compare
Match, OCnB disconnected (normal port operation).
For all other WGM1 settings, normal port operation,
OC1A/OC1B disconnected
10
Clear OCnA/OCnB on Compare Match when up-
counting. Set OCnA/OCnB on Compare Match when
downcounting
11
Set OCnA/OCnB on Compare Match when up-
counting. Clear OCnA/OCnB on Compare Match
when downcounting