Alternate Functions of Port D

The Port D pins with alternate functions are shown in the table below:

Table 1. Port D Pins Alternate Functions
Port Pin Alternate Function
PD7

AIN1 (Analog Comparator Negative Input)

PCINT23 (Pin Change Interrupt 23)

PD6

AIN0 (Analog Comparator Positive Input)

OC0A (Timer/Counter0 Output Compare Match A Output)

PCINT22 (Pin Change Interrupt 22)

PD5

T1 (Timer/Counter 1 External Counter Input)

OC0B (Timer/Counter0 Output Compare Match B Output)

PCINT21 (Pin Change Interrupt 21)

PD4

XCK (USART External Clock Input/Output)

T0 (Timer/Counter 0 External Counter Input)

PCINT20 (Pin Change Interrupt 20)

PD3

INT1 (External Interrupt 1 Input)

OC2B (Timer/Counter2 Output Compare Match B Output)

PCINT19 (Pin Change Interrupt 19)

PD2

INT0 (External Interrupt 0 Input)

PCINT18 (Pin Change Interrupt 18)

PD1

TXD (USART0 Output Pin)

PCINT17 (Pin Change Interrupt 17)

PD0

RXD (USART Input Pin)

PCINT16 (Pin Change Interrupt 16)

The alternate pin configuration is as follows:

The tables below relate the alternate functions of Port D to the overriding signals shown in Figure 1.

Table 2. Overriding Signals for Alternate Functions PD7...PD4
Signal
Name PD7/AIN1
/PCINT23 PD6/AIN0/
OC0A/PCINT22 PD5/T1/OC0B/
PCINT21 PD4/XCK/
T0/PCINT20
PUOE 0 0 0 0
PUO 0 0 0 0
DDOE 0 0 0 0
DDOV 0 0 0 0
PVOE 0 OC0A ENABLE OC0B ENABLE UMSEL
PVOV 0 OC0A OC0B XCK OUTPUT
DIEOE PCINT23 • PCIE2 PCINT22 • PCIE2 PCINT21 • PCIE2 PCINT20 • PCIE2
DIEOV 1 1 1 1
DI PCINT23 INPUT PCINT22 INPUT PCINT21 INPUT
 / T1 INPUT PCINT20 INPUT
 / XCK INPUT
 / T0 INPUT
AIO AIN1 INPUT AIN0 INPUT
Table 3. Overriding Signals for Alternate Functions in PD3...PD0
Signal
Name PD3/OC2B/INT1/
PCINT19 PD2/OC3B/OC4B/INT0/
PCINT18 PD1/TXD/
PCINT17 PD0/RXD/
PCINT16
PUOE 0 0 TXEN RXEN
PUO 0 0 0 PORTD • PUD
DDOE 0 0 TXEN RXEN
DDOV 0 0 1 0
PVOE OC2B ENABLE OC3B/OC4B ENABLE TXEN  
PVOV OC2B OC3B/OC4B TXD  
DIEOE INT1 ENABLE + PCINT19 • PCIE2 INT0 ENABLE + PCINT18 • PCIE2 PCINT17 • PCIE2 PCINT16 • PCIE2
DIEOV 1 1 1 1
DI PCINT19 INPUT
 / INT1 INPUT PCINT18 INPUT
 / INT0 INPUT PCINT17 INPUT PCINT16 INPUT
 / RXD
AIO