Datasheet

98
ATmega640/1280/1281/2560/2561
2549K–AVR–01/07
• INT1/SDA – Port D, Bit 1
INT1, External Interrupt source 1. The PD1 pin can serve as an external interrupt source
to the MCU.
SDA, 2-wire Serial Interface Data: When the TWEN bit in TWCR is set (one) to enable
the 2-wire Serial Interface, pin PD1 is disconnected from the port and becomes the
Serial Data I/O pin for the 2-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.
•INT0/SCL – Port D, Bit 0
INT0, External Interrupt source 0. The PD0 pin can serve as an external interrupt source
to the MCU.
SCL, 2-wire Serial Interface Clock: W hen the TWEN bit in TWCR is set (one) to enable
the 2-wire Serial Interface, pin PD0 is disconnected from the port and becomes the
Serial Clock I/O pin for the 2-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.
Table 49 and Table 50 relates the alternate functions of Port D to the overriding signals
shown in Figure 36 on page 89.
Table 49. Overriding Signals for Alternate Functions PD7:PD4
Signal Name PD7/T0 PD6/T1 PD5/XCK1 PD4/ICP1
PUOE000 0
PUOV000 0
DDOE 0 0 XCK1 OUTPUT ENABLE 0
DDOV 0 0 1 0
PVOE 0 0 XCK1 OUTPUT ENABLE 0
PVOV 0 0 XCK1 OUTPUT 0
DIEOE000 0
DIEOV000 0
DI T0 INPUT T1 INPUT XCK1 INPUT ICP1 INPUT
AIO––– –