Datasheet

• SCL/PCINT16 – Port C, Bit 0
– SCL: two-wire Serial Bus Clock Line.
– PCINT16: Pin Change Interrupt source 16. 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 15-5.
Table 15-10. Overriding Signals for Alternate Functions in PC[7:4]
Signal
Name
PC7/TOSC2/PCINT23 PC6/TOSC1/PCINT22 PC5/TDI/PCINT21 PC4/TDO/PCINT20
PUOE AS2 • EXCLK AS2 JTAGEN JTAGEN
PUOV 0 0 1 1
DDOE AS2 • EXCLK AS2 JTAGEN
JTAGEN
DDOV 0 0 0
SHIFT_IR + SHIFT_DR
PVOE 0 0 0 JTAGEN
PVOV 0 0 0 TDO
DIEOE AS2 • EXCLK + PCINT23 •
PCIE2
AS2 + PCINT22 •
PCIE2
JTAGEN + PCINT21 •
PCIE2
JTAGEN + PCINT20 •
PCIE2
DIEOV AS2 EXCLK + AS2 JTAGEN JTAGEN
DI PCINT23 INPUT PCINT22 INPUT PCINT21 INPUT PCINT20 INPUT
AIO TC2 OSC OUTPUT TC1 OSC INPUT TDI INPUT -
Table 15-11. Overriding Signals for Alternate Functions in PC[3:0]
Signal
Name
PC3/TMS/PCINT19 PC2/TCK/PCINT18 PC1/SDA/PCINT17 PC0/SCL/PCINT16
PUOE JTAGEN JTAGEN TWEN TWEN
PUOV 1 1 PORTC1 • PUD PORTC0 • PUD
DDOE JTAGEN JTAGEN TWEN TWEN
DDOV 0 0 0 0
PVOE 0 0 TWEN TWEN
PVOV 0 0 SDA OUT SCL OUT
DIEOE JTAGEN + PCINT19 • PCIE2 JTAGEN + PCINT18 • PCIE2 PCINT17 • PCIE2 PCINT16 • PCIE2
DIEOV JTAGEN JTAGEN 1 1
DI
PCINT19 INPUT PCINT18 INPUT
PCINT17 INPUT PCINT16 INPUT
AIO TMS INPUT TCK INPUT SDA INPUT SCL INPUT
15.3.4. Alternate Functions of Port D
The Port D pins with alternate functions are shown in the table below:
Atmel ATmega644A [DATASHEET]
Atmel-42716C-ATmega644A_Datasheet_Complete-10/2016
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