Table 16-2, Table 16-3, Table 16-2 on – Rainbow Electronics ATmega64M1 User Manual
Page 125: Table 16-3 on, Table on, The actual ocnx
125
8209A–AVR–08/09
ATmega16M1/32M1/64M1
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 match is ignored, but the set or clear is done at TOP.
for more details.
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.
“Phase Correct PWM Mode” on page 118.
for more details.
• 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 wave-
form generation to be used, see
. 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 “16-bit Timer/Counter1 with PWM” on page
Table 16-2.
Compare Output Mode, Fast PWM
COMnA1/COMnB1
COMnA0/COMnB0
Description
0
0
Normal port operation, OCnA/OCnB disconnected.
0
1
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.
1
0
Clear OCnA/OCnB on Compare Match, set
OCnA/OCnB at TOP
1
1
Set OCnA/OCnB on Compare Match, clear
OCnA/OCnB at TOP
Table 16-3.
Compare Output Mode, Phase Correct and Phase and Frequency Correct
PWM
COMnA1/COMnB1
COMnA0/COMnB0
Description
0
0
Normal port operation, OCnA/OCnB disconnected.
0
1
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.
1
0
Clear OCnA/OCnB on Compare Match when up-
counting. Set OCnA/OCnB on Compare Match when
downcounting.
1
1
Set OCnA/OCnB on Compare Match when up-
counting. Clear OCnA/OCnB on Compare Match
when downcounting.