
127
ATmega64A [DATASHEET]
8160D–AVR–02/2013
Table 16-3 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/OCRnC equals TOP and COMnA1/COMnB1/COMnC1 is set. In this
for more details.
Table 16-3 shows the COMnx1:0 bit functionality when the WGMn3:0 bits are set to the phase correct and fre-
quency correct PWM mode.
Note:
1. A special case occurs when OCRnA/OCRnB/OC
RnC equals TOP and COMnA1/COMnB1/COMnC1 is set. See Bit 1:0 – WGMn1:0: Waveform Generation 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 generation to be used, see
Table 16-5. Modes of operation supported by the Timer/Counter unit are: Normal mode (counter), Clear Timer on
Compare match (CTC) mode, and three types of Pulse Width Modulation (PWM) modes. (
See “Modes of Opera-Table 16-3.
Compare Output Mode, Fast
PWMCOMnA1/
COMnB1/
COMnC0
COMnA0/
COMnB0/
COMnC0
Description
0
Normal port operation, OCnA/OCnB/OCnC disconnected.
0
1
WGMn3:0 = 15: Toggle OCnA on Compare Match, OCnB/OCnC disconnected (normal
port operation).
For all other WGMn settings, normal port operation, OCnA/OCnB/OCnC disconnected.
1
0
Clear OCnA/OCnB/OCnC on Compare Match, set OCnA/OCnB/OCnC at BOTTOM (non-
inverting mode).
1
Set OCnA/OCnB/OCnC on Compare Match, clear OCnA/OCnB/OCnC at BOTTOM
(inverting mode).
Table 16-4.
Compare Output Mode, Phase Correct and Phase and Frequency Correct
PWMCOMnA1/
COMnB1/
COMnC1
COMnA0/
COMnB0/
COMnC0
Description
0
Normal port operation, OCnA/OCnB/OCnC disconnected.
0
1
WGMn3:0 = 9 or 11: Toggle OCnA on Compare Match, OCnB/OCnC disconnected
(normal port operation).
Forr all other WGMn settings, normal port operation, OCnA/OCnB/OCnC disconnected.
1
0
Clear OCnA/OCnB/OCnC on Compare Match when up-counting. Set OCnA/OCnB/OCnC
on Compare Match when downcounting.
1
Set OCnA/OCnB/OCnC on Compare Match when up-counting. Clear OCnA/OCnB/OCnC
on Compare Match when downcounting.