Datasheet

 2018 Microchip Technology Inc. Data Sheet Complete DS40002060A-page 82
ATtiny4/5/9/10
When OC0A or OC0B is connected to the pin, the function of COM0x1:0 bits depends on the WGM03:0 bits. Table 12-2
shows the COM0x1:0 bit functionality when the WGM03:0 bits are set to a Normal or CTC (non-PWM) Mode.
Table 12-3 shows the COM0x1:0 bit functionality when the WGM03:0 bits are set to one of the Fast PWM Modes.
Note: 1. A special case occurs when OCR0A/OCR0B equals TOP and COM0A1/COM0B1 is set. In this case the compare match is
ignored, but set or clear is done at BOTTOM. See “Fast PWM Mode” on page 72 for more details.
Table 12-4 shows the COM0x1:0 bit functionality when the WGM03:0 bits are set to the phase correct or the phase and fre-
quency correct, PWM mode.
Note: 1. A special case occurs when OCR0A/OCR0B equals TOP and COM0A1/COM0B1 is set. “Phase Correct PWM Mode” on
page 74 for more details.
• Bits 1:0 – WGM01:0: Waveform Generation Mode
Combined with WGM03:2 bits of TCCR0B, these bits control the counting sequence of the counter, the source for maxi-
mum (TOP) counter value, and what type of waveform to generate. See Table 12-5. Modes of operation supported by the
Table 12-2. Compare Output in Non-PWM Modes
COM0A1/
COM0B1
COM0A0
COM0B0 Description
0
0 Normal port operation: OC0A/OC0B disconnected
1 Toggle OC0A/OC0B on compare match
1
0 Clear (set low) OC0A/OC0B on compare match
1 Set (high) OC0A/OC0B on compare match
Table 12-3. Compare Output in Fast PWM Modes
COM0A1/
COM0B1
COM0A0/
COM0B0 Description
0
0 Normal port operation: OC0A/OC0B disconnected
1
WGM03 = 0: Normal port operation, OC0A/OC0B disconnected
WGM03 = 1: Toggle OC0A on compare match, OC0B reserved
1
(1)
0
Clear OC0A/OC0B on compare match
Set OC0A/OC0B at BOTTOM (non-inverting mode)
1
Set OC0A/OC0B on compare match
Clear OC0A/OC0B at BOTTOM (inverting mode)
Table 12-4. Compare Output in Phase Correct and Phase & Frequency Correct PWM Modes
COM0A1/
COM0B1
COM0A0/
COM0B0 Description
0
0 Normal port operation: OC0A/OC0B disconnected.
1
WGM03 = 0: Normal port operation, OC0A/OC0B disconnected
WGM03 = 1: Toggle OC0A on compare match, OC0B reserved
1
(1)
0
Counting up: Clear OC0A/OC0B on compare match
Counting down: Set OC0A/OC0B on compare match
1
Counting up: Set OC0A/OC0B on compare match
Counting down: Clear OC0A/OC0B on compare match