The Port C pins with alternate functions
are shown in the table below:
Table 1. Port C Pins Alternate Functions
Port Pin |
Alternate Function |
PC6 |
RESET (Reset pin)
PCINT14 (Pin Change Interrupt 14)
|
PC5 |
ADC5 (ADC Input Channel 5)
SCL0 (two-wire Serial Bus Clock Line)
PCINT13 (Pin Change Interrupt 13)
|
PC4 |
ADC4 (ADC Input Channel 4)
SDA0 (two-wire Serial Bus Data Input/Output Line)
PCINT12 (Pin Change Interrupt 12)
|
PC3 |
ADC3 (ADC Input Channel 3)
PCINT11 (Pin Change Interrupt 11)
|
PC2 |
ADC2 (ADC Input Channel 2)
PCINT10 (Pin Change Interrupt 10)
|
PC1 |
SCK1 (SPI1 Master Clock output)
ADC1 (ADC Input Channel 1)
PCINT9 (Pin Change Interrupt 9)
|
PC0 |
MISO1
ADC0 (ADC Input Channel 0)
PCINT8 (Pin Change Interrupt 8)
|
The alternate pin configuration is as
follows:
- RESET/PCINT14 – Port C, Bit 6
- RESET, Reset pin: When the
RSTDISBL Fuse is programmed, this pin functions as a normal I/O pin, and the part
will have to rely on Power-on Reset and Brown-out Reset as its reset sources. When
the RSTDISBL Fuse is unprogrammed, the reset circuitry is connected to the pin,
and the pin cannot be used as an I/O pin.
- PCINT14: Pin Change Interrupt source 14. The PC6 pin can serve as an external
interrupt source.
If PC6 is used as a reset pin, DDC6, PORTC6
and PINC6 will all read 0.
- SCL0/ADC5/PCINT13 – Port C, Bit 5
- SDA0/ADC4/PCINT12 – Port C, Bit 4
- SDA0: Two-wire Serial Interface0
Data. When the TWEN bit in TWCR0 is set (one) to enable the two-wire Serial
Interface, pin PC4 is disconnected from the port and becomes the Serial Data I/O
pin for the two-wire Serial Interface0. In this mode, there is a spike filter on
the pin to suppress spikes shorter than 50 ns on the input signal, and the pin is
driven by an open drain driver with slew-rate limitation.
- PCINT12: Pin Change Interrupt source 12. The PC4 pin can serve as an external
interrupt source.
- PC4 can also be used as ADC input Channel 4. The ADC input channel 4 uses digital
power.
- ADC3/PCINT11 – Port C, Bit 3
- PC3 can also be used as ADC input Channel 3. The ADC input channel 3 uses analog
power.
- PCINT11: Pin Change Interrupt source 11. The PC3 pin can serve as an external
interrupt source.
- ADC2/PCINT10 – Port C, Bit 2
- PC2 can also be used as ADC input Channel 2. The ADC input channel 2 uses analog
power.
- PCINT10: Pin Change Interrupt source 10. The PC2 pin can serve as an external
interrupt source.
- ADC0/MISO1/PCINT8 – Port C, Bit 0
- PC0 can also be used as ADC input
Channel 0. The ADC input channel 0 uses analog power.
- MISO1: Master1 Data input, Slave Data output pin for SPI1 channel. When the SPI1
is enabled as a Master, this pin is configured as an input regardless of the
setting of DDC0. When the SPI1 is enabled as a Slave, the data direction of this
pin is controlled by DDC0. When the pin is forced by the SPI1 to be an input, the
pull-up can still be controlled by the PORTC0 bit.
- PCINT8: Pin Change Interrupt
source 8. The PC0 pin can serve as an external interrupt source.
The tables below relate the alternate
functions of Port C to the overriding signals shown in Figure 1.
Table 2. Overriding Signals for Alternate
Functions in PC6...PC4(1)
Signal
Name |
PC6/RESET/PCINT14 |
PC5/SCL0/ADC5/PCINT13 |
PC4/SDA0/ADC4/PCINT12 |
PUOE |
RSTDISBL |
TWEN0 |
TWEN0 |
PUOV |
1 |
PORTC5 •
PUD |
PORTC4 •
PUD |
DDOE |
RSTDISBL |
TWEN0 |
TWEN0 |
DDOV |
0 |
SCL_OUT0 |
SDA_OUT0 |
PVOE |
0 |
TWEN0 |
TWEN0 |
PVOV |
0 |
0 |
0 |
DIEOE |
RSTDISBL + PCINT14 • PCIE1 |
PCINT13 • PCIE1 + ADC5D |
PCINT12 • PCIE1 + ADC4D |
DIEOV |
RSTDISBL |
PCINT13 • PCIE1 |
PCINT12 • PCIE1 |
DI |
PCINT14 INPUT |
PCINT13 INPUT |
PCINT12 INPUT |
AIO |
RESET INPUT |
ADC5 INPUT /
SCL0 INPUT |
ADC4 INPUT /
SDA INPUT0 |
Note: 1. When enabled, the two-wire Serial
Interface enables slew-rate controls on the output pins PC4 and PC5. This is not shown
in the figure. In addition, spike filters are connected between the AIO outputs shown in
the port figure and the digital logic of the TWI module.
Table 3. Overriding Signals for Alternate Functions in PC3...PC0
Signal
Name |
PC3/ADC3/
PCINT11 |
PC2/ADC2/
PCINT10 |
PC1/ADC1/SCK1/
PCINT9 |
PC0/ADC0/MISO1/
PCINT8 |
PUOE |
0 |
0 |
SPE1 •
MSTR |
SPE1 •
MSTR |
PUOV |
0 |
0 |
PORTC1 •
PUD |
PORTC0 •
PUD |
DDOE |
0 |
0 |
SPE1 •
MSTR |
SPE1 •
MSTR |
DDOV |
0 |
0 |
0 |
0 |
PVOE |
0 |
0 |
SPE1 •
MSTR |
SPE1 •
MSTR |
PVOV |
0 |
0 |
SCK1
OUTPUT |
SPI1 SLAVE
INPUT |
DIEOE |
PCINT11 • PCIE1 +
ADC3D |
PCINT10 • PCIE1 +
ADC2D |
PCINT9 • PCIE1 +
ADC1D |
PCINT8 • PCIE1 +
ADC0D |
DIEOV |
PCINT11 • PCIE1 |
PCINT10 • PCIE1 |
PCINT9 • PCIE1 |
PCINT8 • PCIE1 |
DI |
PCINT11 INPUT |
PCINT10 INPUT |
PCINT9 INPUT
SCK1 INPUT
|
PCINT8 INPUT
SPI1 MASTER INPUT
|
AIO |
ADC3 INPUT |
ADC2 INPUT |
ADC1 INPUT |
ADC0 INPUT |