Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Ficha De Dados
Códigos do produto
MEGA328P-XMINI
105
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
15.9
Register Description
15.9.1 TCCR0A – Timer/Counter Control Register A
• Bits 7:6 – COM0A1:0: Compare Match Output A Mode
These bits control the Output Compare pin (OC0A) behavior. If one or both of the COM0A1:0 bits are set, the
OC0A 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 OC0A pin must be set in order to enable the output driver.
OC0A 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 OC0A pin must be set in order to enable the output driver.
When OC0A is connected to the pin, the function of the COM0A1:0 bits depends on the WGM02:0 bit setting.
shows the COM0A1:0 bit functionality when the WGM02:0 bits are set to a normal or CTC mode
(non-PWM).
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 BOTTOM. See
ignored, but the set or clear is done at BOTTOM. See
shows the COM0A1:0 bit functionality when the WGM02:0 bits are set to phase correct PWM mode.
Bit
7
6
5
4
3
2
1
0
COM0A1
COM0A0
COM0B1
COM0B0
–
–
WGM01
WGM00
TCCR0A
Read/Write
R/W
R/W
R/W
R/W
R
R
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
Table 15-2.
Compare Output Mode, non-PWM Mode
COM0A1
COM0A0
Description
0
0
Normal port operation, OC0A disconnected.
0
1
Toggle OC0A on Compare Match
1
0
Clear OC0A on Compare Match
1
1
Set OC0A on Compare Match
Table 15-3.
Compare Output Mode, Fast PWM Mode
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.
WGM02 = 1: Toggle OC0A on Compare Match.
1
0
Clear OC0A on Compare Match, set OC0A at BOTTOM,
(non-inverting mode).
(non-inverting mode).
1
1
Set OC0A on Compare Match, clear OC0A at BOTTOM,
(inverting mode).
(inverting mode).