attiny13-20ss ATMEL Corporation, attiny13-20ss Datasheet - Page 70

• Manufacturer Part Number: attiny13-20ss
• Description: 8-bit Microcontroller With 1k Bytes In-system Programmable Flash - Atmel Corporation
• Manufacturer: ATMEL Corporation

70
ATtiny13
Table 28 shows the COM0A1:0 bit functionality when the WGM02:0 bits are set to
phase correct PWM mode.
Table 28. Compare Output Mode, Phase Correct PWM Mode
Note:
• Bits 5:4 – COM0B1:0: Compare Match Output B Mode
These bits control the Output Compare pin (OC0B) behavior. If one or both of the
COM0B1:0 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 cor-
responding 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 COM0B1:0 bits depends on the
WGM02:0 bit setting. Table 26 shows the COM0A1:0 bit functionality when the
WGM02:0 bits are set to a normal or CTC mode (non-PWM).
Table 29. Compare Output Mode, non-PWM Mode
Table 27 shows the COM0B1:0 bit functionality when the WGM02:0 bits are set to fast
PWM mode.
Table 30. Compare Output Mode, Fast PWM Mode
Note:
COM0A1
COM01
COM01
0
0
1
1
0
0
1
1
0
0
1
1
1. A special case occurs when OCR0A equals TOP and COM0A1 is set. In this case,
1. A special case occurs when OCR0B equals TOP and COM0B1 is set. In this case,
the Compare Match is ignored, but the set or clear is done at TOP. See “Phase Cor-
rect PWM Mode” on page 66 for more details.
the Compare Match is ignored, but the set or clear is done at TOP. See “Fast PWM
Mode” on page 64 for more details.
COM0A0
COM00
COM00
0
1
0
1
0
1
0
1
0
1
0
1
Description
Normal port operation, OC0A disconnected.
WGM02 = 0: Normal Port Operation, OC0A Disconnected.
WGM02 = 1: Toggle OC0A on Compare Match.
Clear OC0A on Compare Match when up-counting. Set OC0A on
Compare Match when down-counting.
Set OC0A on Compare Match when up-counting. Clear OC0A on
Compare Match when down-counting.
Description
Normal port operation, OC0B disconnected.
Toggle OC0B on Compare Match
Clear OC0B on Compare Match
Set OC0B on Compare Match
Description
Normal port operation, OC0B disconnected.
Reserved
Clear OC0B on Compare Match, set OC0B at TOP
Set OC0B on Compare Match, clear OC0B at TOP
(1)
(1)
2535G–AVR–01/07