ATMEGA8U2_14 Datasheet, PDF (79/310 Pages) ATMEL Corporation – 125 Powerful Instructions – Most Single Clock Cycle Execution

ATmega8U2/16U2/32U2
12.3.3
Alternate Functions of Port D
The Port D pins with alternate functions are shown in Table 12-9.
Table 12-9.
Port Pin
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
Port D Pins Alternate Functions
Alternate Function
HWB/TO/INT7/CTS
INT6/RTS
XCK1/PCINT12 (USART1 External Clock Input/Output)
INT5
INT3/TXD1 (External Interrupt3 Input or USART1 Transmit Pin)
INT2/AIN1/RXD1(External Interrupt2 Input or USART1 Receive Pin)
INT1/AIN0 (External Interrupt1 Input)
INT0/OC0B (External Interrupt0 Input)
The alternate pin configuration is as follows:
• HWB/TO/INT7/CTS, Bit 7
HWB, Hardware Boot : The PD7 pin can serve as
TO, Timer/Counter0 counter source.
INT7, External Interrupt source 7: The PD7 pin can serve as an external interrupt source to the
MCU.
CTS, USART1 Transmitter Flow Control. This pin can control the transmitter in function of its
state.
• INT6/RTS,Bit 6
INT6, External Interrupt source 6: The PD6 pin can serve as an external interrupt source to the
MCU.
RTS, USART1 Receiver Flow Control. This pin can control the receiver in function of its state.
• XCK1/PCINT12, Bit 5
XCK1, USART1 External Clock : The data direction register DDRD5 controls whether the clock
is output (DDRD5 set) or input (DDRD5 cleared). The XCK1 pin is active only when the USART1
operates in Synchronous Mode.
PCINT12, Pin Change Interrupt source 12: The PD5 pin can serve as an external interrupt
source.
• INT5, Bit 4
INT5, External Interrupt source 5: The PD4 pin can serve as an external interrupt source to the
MCU.
• INT3/TXD1, Bit 3
INT3, External Interrupt source 3: The PD3 pin can serve as an external interrupt source to the
MCU.
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