Each pin is by default controlled by the PORT as a general purpose I/O and
alternatively it can be assigned to one of the peripheral functions. The following table
describes the peripheral signals multiplexed to the PORT I/O pins.
Table 1. PORT Function
Multiplexing
14-pin |
8-pin |
Pin name |
Special |
INT(3) |
ADC(3) |
AC |
USART |
Timer |
Programming(8) |
1 |
1(1) |
VCC |
|
|
|
|
|
|
|
2 |
2 |
PA[0](2) |
CLKI |
PCINT0 |
ADC0 |
AIN0 |
|
T0 |
TPICLK |
3 |
3 |
PA[1](5) |
|
PCINT1 |
ADC1 |
AIN1 |
|
OC0B |
TPIDATA |
4 |
4 |
PA[2] |
RESET |
PCINT2 |
|
|
|
|
RESET |
5 |
- |
PA[3](9) |
|
PCINT3 |
|
|
|
OC0A |
|
6 |
- |
PA[4](9) |
|
PCINT4 |
|
|
|
ICP0 |
|
7 |
- |
PA[5](5)(9) |
|
PCINT5 |
ADC2 |
|
|
OC0B |
|
8 |
- |
PA[6] |
|
PCINT6 |
ADC3 |
|
|
|
|
9 |
- |
PA[7] |
|
PCINT7 |
|
|
|
|
|
10 |
- |
PB[0] |
|
PCINT8 |
ADC4 |
|
|
|
|
11 |
5 |
PB[1](6) |
CLKO |
PCINT9/INT0 |
ADC5 |
|
XCK0 |
OC0A |
|
12 |
6 |
PB[2](7) |
|
PCINT10 |
ADC6 |
|
TxD0 |
ICP0 |
|
13 |
7 |
PB[3](4)(9) |
|
PCINT11 |
ADC7 |
ACO |
RxD0 |
T0 |
|
14 |
8 |
GND |
|
|
|
|
|
|
|
Note:
- 1.On the 8-pin UDFN package,
the thermal pad should not be connected as well.
- 2.Priority of CLKI is higher
than ADC0. When EXT_CLK is enabled, ADC channel will not work and DIDR0 will
not disable the digital input buffer.
- 3.When both PCINT and the
corresponding ADC channel are enabled, the digital input buffer will not be
disabled.
- 4.When ACO is enabled, ADC, TC
and USART RX inputs are not disabled.
- 5.When OC0B is enabled, ADC and
AC will continue to receive inputs on that channel if enabled.
- 6.When CLKO is enable in PB[1],
OCA will get lower priority.
- 7.When USART is enabled, the
users must ensure that ADC channel corresponding to the TxD0 pin is not
used. Because DIDR0 register will only control the input buffer, not the
output part.
- 8.During reset/external
programming, all pins are treated as inputs and outputs are disabled.
- 9.Alternative location when enabling T/C Remap