Datasheet

• SCL/ADC5 – Port C, Bit 5

SCL, Two-wire Serial Interface Clock: When the TWEN bit in TWCR is set (one) to enable the Two-wire

Serial Interface, pin PC5 is disconnected from the port and becomes the Serial Clock I/O pin for the Two-

wire Serial Interface. 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.

PC5 can also be used as ADC input Channel 5. Note that ADC input channel 5 uses digital power.

• SDA/ADC4 – Port C, Bit 4

SDA, Two-wire Serial Interface Data: When the TWEN bit in TWCR 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 Interface. 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.

PC4 can also be used as ADC input Channel 4. Note that ADC input channel 4 uses digital power.

• ADC3 – Port C, Bit 3

PC3 can also be used as ADC input Channel 3. Note that ADC input channel 3 uses analog power.

• ADC2 – Port C, Bit 2

PC2 can also be used as ADC input Channel 2. Note that ADC input channel 2 uses analog power.

• ADC1 – Port C, Bit 1

PC1 can also be used as ADC input Channel 1. Note that ADC input channel 1 uses analog power.

• ADC0 – Port C, Bit 0

PC0 can also be used as ADC input Channel 0. Note that ADC input channel 0 uses analog power.

The tables below relate the alternate functions of Port C to the overriding signals shown in figure Figure

18-5.

Table 18-7. Overriding Signals for Alternate Functions in PC6:PC4

Signal

Name

PC6/RESET PC5/SCL/ADC5 PC4/SDA/ADC4

PUOE RSTDISBL TWEN TWEN

PUOV 1 PORTC5 • PUD PORTC4 • PUD

DDOE RSTDISBL TWEN TWEN

DDOV 0 SCL_OUT SDA_OUT

PVOE 0 TWEN TWEN

PVOV 0 0 0

DIEOE RSTDISBL 0 0

DIEOV 0 0 0

DI – – –

AIO RESET INPUT ADC5 INPUT / SCL INPUT ADC4 INPUT / SDA INPUT

AVR 8-Bit Microcontroller

I/O Ports

Datasheet Complete

40001974A-page 90