Datasheet

109
8006H–AVR–10/09
ATtiny24/44/84
Table 12-3 shows the COM1x1:0 bit functionality when the WGM13:0 bits are set to the fast
PWM mode.
Note: 1. A special case occurs when OCR1A/OCR1B equals TOP and COM1A1/COM1B1 is set. In
this case the compare match is ignored, but the set or clear is done at BOTTOM. “Fast PWM
Mode” on page 97 for more details.
Table 12-4 shows the COM1x1:0 bit functionality when the WGM13:0 bits are set to the phase
correct or the phase and frequency correct, PWM mode.
Note: 1. A special case occurs when OCR1A/OCR1B equals TOP and COM1A1/COM1B1 is set.
“Phase Correct PWM Mode” on page 99 for more details.
Table 12-2. Compare Output Mode, non-PWM
COM1A1/COM1B1 COM1A0/COM1B0 Description
00Normal port operation, OC1A/OC1B disconnected.
0 1 Toggle OC1A/OC1B on Compare Match.
10
Clear OC1A/OC1B on Compare Match (Set output to
low level).
11
Set OC1A/OC1B on Compare Match (Set output to
high level).
Table 12-3. Compare Output Mode, Fast PWM
(1)
COM1A1/COM1B1 COM1A0/COM1B0 Description
00Normal port operation, OC1A/OC1B disconnected.
01
WGM13=0: Normal port operation, OC1A/OC1B
disconnected.
WGM13=1: Toggle OC1A on Compare Match, OC1B
reserved.
10
Clear OC1A/OC1B on Compare Match, set
OC1A/OC1B at BOTTOM (non-inverting mode)
11
Set OC1A/OC1B on Compare Match, clear
OC1A/OC1B at BOTTOM (inverting mode)
Table 12-4. Compare Output Mode, Phase Correct and Phase & Frequency Correct PWM
(1)
COM1A1/COM1B1 COM1A0/COM1B0 Description
00Normal port operation, OC1A/OC1B disconnected.
01
WGM13=0: Normal port operation, OC1A/OC1B
disconnected.
WGM13=1: Toggle OC1A on Compare Match, OC1B
reserved.
10
Clear OC1A/OC1B on Compare Match when up-
counting. Set OC1A/OC1B on Compare Match when
downcounting.
11
Set OC1A/OC1B on Compare Match when up-
counting. Clear OC1A/OC1B on Compare Match
when downcounting.