Datasheet

61
ATmega8(L)
2486M–AVR–12/03
Alternate Functions of Port D The Port D pins with alternate functions are shown in Table 28.
The alternate pin configuration is as follows:
• AIN1 – Port D, Bit 7
AIN1, Analog Comparator Negative Input. Configure the port pin as input with the inter-
nal pull-up switched off to avoid the digital port function from interfering with the function
of the Analog Comparator.
• AIN0 – 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.
• T1 – Port D, Bit 5
T1, Timer/Counter1 counter source.
• XCK/T0 – Port D, Bit 4
XCK, USART external clock.
T0, Timer/Counter0 counter source.
• INT1 – Port D, Bit 3
INT1, External Interrupt source 1: The PD3 pin can serve as an external interrupt
source.
• INT0 – Port D, Bit 2
INT0, External Interrupt source 0: The PD2 pin can serve as an external interrupt
source.
• TXD – Port D, Bit 1
TXD, Transmit Data (Data output pin for the USART). When the USART Transmitter is
enabled, this pin is configured as an output regardless of the value of DDD1.
• RXD – Port D, Bit 0
RXD, Receive Data (Data input pin for the USART). When the USART Receiver is
enabled this pin is configured as an input regardless of the value of DDD0. When the
USART forces this pin to be an input, the pull-up can still be controlled by the
PORTD0 bit.
Table 28. Port D Pins Alternate Functions
Port Pin Alternate Function
PD7 AIN1 (Analog Comparator Negative Input)
PD6 AIN0 (Analog Comparator Positive Input)
PD5 T1 (Timer/Counter 1 External Counter Input)
PD4
XCK (USART External Clock Input/Output)
T0 (Timer/Counter 0 External Counter Input)
PD3 INT1 (External Interrupt 1 Input)
PD2 INT0 (External Interrupt 0 Input)
PD1 TXD (USART Output Pin)
PD0 RXD (USART Input Pin)