Datasheet
1. A special case occurs when OCR0A equals TOP and COM0A1 is set. In this case the compare
match is ignored, but the set or clear is done at BOTTOM. Refer to Fast PWM Mode for details.
The table below shows the COM0A[1:0] bit functionality when the WGM0[2:0] bits are set to phase
correct PWM mode.
Table 15-5. Compare Output Mode, Phase Correct PWM Mode
(1)
COM0A1 COM0A0 Description
0 0 Normal port operation, OC0A disconnected.
0 1 WGM02 = 0: Normal Port Operation, OC0A Disconnected.
WGM02 = 1: Toggle OC0A on Compare Match.
1 0 Clear OC0A on Compare Match when up-counting. Set OC0A on Compare Match
when down-counting.
1 1 Set OC0A on Compare Match when up-counting. Clear OC0A on Compare Match
when down-counting.
Note:
1. A special case occurs when OCR0A equals TOP and COM0A1 is set. In this case, the Compare
Match is ignored, but the set or clear is done at TOP. Refer to Phase Correct PWM Mode for
details.
Bits 5:4 – COM0Bn: Compare Output Mode for Channel B [n = 1:0]
These bits control the Output Compare pin (OC0B) behavior. If one or both of the COM0B[1:0] bits are
set, the OC0B output overrides the normal port functionality of the I/O pin it is connected to. However,
note that the Data Direction Register (DDR) bit corresponding to the OC0B pin must be set in order to
enable the output driver.
When OC0B is connected to the pin, the function of the COM0B[1:0] bits depends on the WGM0[2:0] bit
setting. The table shows the COM0B[1:0] bit functionality when the WGM0[2:0] bits are set to a normal or
CTC mode (non- PWM).
Table 15-6. Compare Output Mode, non-PWM
COM0B1 COM0B0 Description
0 0 Normal port operation, OC0B disconnected.
0 1 Toggle OC0B on Compare Match.
1 0 Clear OC0B on Compare Match.
1 1 Set OC0B on Compare Match.
The table below shows the COM0B[1:0] bit functionality when the WGM0[2:0] bits are set to fast PWM
mode.
Table 15-7. Compare Output Mode, Fast PWM
(1)
COM0B1 COM0B0 Description
0 0 Normal port operation, OC0B disconnected.
0 1 Reserved
Atmel ATmega16M1/32M1/64M1 [DATASHEET]
Atmel-8209F-ATmega16M1/32M1/64M1_Datasheet_Complete-10/2016
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