10.3.4
Alternate Functions of Port D
The Port D pins with alternate functions are shown in Table 10-9.
Table 10-9. Port D Pins Alternate Functions
Port Pin
Alternate Function
AIN1 (Analog Comparator Negative Input)
PCINT23 (Pin Change Interrupt 23)
PD7
AIN0 (Analog Comparator Positive Input)
OC0A (Timer/Counter0 Output Compare Match A Output)
PCINT22 (Pin Change Interrupt 22)
PD6
PD5
PD4
PD3
T1 (Timer/Counter 1 External Counter Input)
OC0B (Timer/Counter0 Output Compare Match B Output)
PCINT21 (Pin Change Interrupt 21)
XCK (USART External Clock Input/Output)
T0 (Timer/Counter 0 External Counter Input)
PCINT20 (Pin Change Interrupt 20)
INT1 (External Interrupt 1 Input)
OC2B (Timer/Counter2 Output Compare Match B Output)
PCINT19 (Pin Change Interrupt 19)
INT0 (External Interrupt 0 Input)
PCINT18 (Pin Change Interrupt 18)
PD2
PD1
PD0
TXD (USART Output Pin)
PCINT17 (Pin Change Interrupt 17)
RXD (USART Input Pin)
PCINT16 (Pin Change Interrupt 16)
The alternate pin configuration is as follows:
• AIN1/OC2B/PCINT23 – Port D, Bit 7
AIN1, Analog Comparator Negative Input. Configure the port pin as input with the internal pull-up
switched off to avoid the digital port function from interfering with the function of the Analog
Comparator.
PCINT23: Pin Change Interrupt source 23. The PD7 pin can serve as an external interrupt
source.
• AIN0/OC0A/PCINT22 – Port D, Bit 6
AIN0, Analog Comparator Positive Input. Configure the port pin as input with the internal pull-up
switched off to avoid the digital port function from interfering with the function of the Analog
Comparator.
OC0A, Output Compare Match output: The PD6 pin can serve as an external output for the
Timer/Counter0 Compare Match A. The PD6 pin has to be configured as an output (DDD6 set
(one)) to serve this function. The OC0A pin is also the output pin for the PWM mode timer
function.
PCINT22: Pin Change Interrupt source 22. The PD6 pin can serve as an external interrupt
source.
78
ATmega48/88/168
2545E–AVR–02/05
MICROCHIP [ MICROCHIP ]
