81
2467S–AVR–07/09
ATmega128
Alternate Functions of
Port E
The Port E pins with alternate functions are shown in
Note:
1. ICP3, T3, OC3C, OC3B, OC3B, OC3A, and XCK0 not applicable in ATmega103 compatibility
mode.
• INT7/ICP3 – Port E, Bit 7
INT7, External Interrupt source 7: The PE7 pin can serve as an external interrupt source.
ICP3 – Input Capture Pin3: The PE7 pin can act as an Input Capture Pin for Timer/Counter3.
• INT6/T3 – Port E, Bit 6
INT6, External Interrupt source 6: The PE6 pin can serve as an external interrupt source.
T3, Timer/Counter3 counter source.
• INT5/OC3C – Port E, Bit 5
INT5, External Interrupt source 5: The PE5 pin can serve as an External Interrupt source.
OC3C, Output Compare Match C output: The PE5 pin can serve as an External output for the
Timer/Counter3 Output Compare C. The pin has to be configured as an output (DDE5 set “one”)
to serve this function. The OC3C pin is also the output pin for the PWM mode timer function.
• INT4/OC3B – Port E, Bit 4
INT4, External Interrupt source 4: The PE4 pin can serve as an External Interrupt source.
OC3B, Output Compare Match B output: The PE4 pin can serve as an External output for the
Timer/Counter3 Output Compare B. The pin has to be configured as an output (DDE4 set (one))
to serve this function. The OC3B pin is also the output pin for the PWM mode timer function.
• AIN1/OC3A – Port E, Bit 3
AIN1 – Analog Comparator Negative input. This pin is directly connected to the negative input of
the Analog Comparator.
OC3A, Output Compare Match A output: The PE3 pin can serve as an External output for the
Timer/Counter3 Output Compare A. The pin has to be configured as an output (DDE3 set “one”)
to serve this function. The OC3A pin is also the output pin for the PWM mode timer function.
• AIN0/XCK0 – Port E, Bit 2
AIN0 – Analog Comparator Positive input. This pin is directly connected to the positive input of
the Analog Comparator.
Table 39.
Port E Pins Alternate Functions
Port Pin
Alternate Function
PE7
INT7/ICP3
(External Interrupt 7 Input or Timer/Counter3 Input Capture Pin)
PE6
(External Interrupt 6 Input or Timer/Counter3 Clock Input)
PE5
INT5/OC3C
(External Interrupt 5 Input or Output Compare and PWM Output C
for Timer/Counter3)
PE4
INT4/OC3B
(External Interrupt4 Input or Output Compare and PWM Output B for
Timer/Counter3)
PE3
(Analog Comparator Negative Input or Output Compare and PWM
Output A for Timer/Counter3)
PE2
AIN0/XCK0
(Analog Comparator Positive Input or USART0 external clock
input/output)
PE1
PDO/TXD0 (Programming Data Output or UART0 Transmit Pin)
PE0
PDI/RXD0 (Programming Data Input or UART0 Receive Pin)
