Datasheet

6.1.7. Port E (PE7:PE0)
Port E is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port E
output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs,
Port E pins that are externally pulled low will source current if the pull-up resistors are activated. The Port
E pins are tristated when a reset condition becomes active, even if the clock is not running.
Port E also serves the functions of various special features of the ATmega64A as listed in Alternate
Functions of Port E.
Related Links
Alternate Functions of Port E on page 105
6.1.8. Port F (PF7:PF0)
Port F serves as the analog inputs to the A/D Converter.
Port F also serves as an 8-bit bi-directional I/O port, if the A/D Converter is not used. Port pins can
provide internal pull-up resistors (selected for each bit). The Port F output buffers have symmetrical drive
characteristics with both high sink and source capability. As inputs, Port F pins that are externally pulled
low will source current if the pull-up resistors are activated. The Port F pins are tri-stated when a reset
condition becomes active, even if the clock is not running. If the JTAG interface is enabled, the pull-up
resistors on pins PF7(TDI), PF5(TMS), and PF4(TCK) will be activated even if a Reset occurs.
The TDO pin is tri-stated unless TAP states that shift out data are entered.
Port F also serves the functions of the JTAG interface.
In ATmega103 compatibility mode, Port F is an input Port only.
Related Links
Alternate Functions of Port F on page 108
6.1.9. Port G (PG4:PG0)
Port G is a 5-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port G
output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs,
Port G pins that are externally pulled low will source current if the pull-up resistors are activated. The Port
G pins are tristated when a reset condition becomes active, even if the clock is not running.
Port G also serves the functions of various special features.
The port G pins are tri-stated when a reset condition becomes active, even if the clock is not running.
In Atmel AVR ATmega103 compatibility mode, these pins only serves as strobes signals to the external
memory as well as input to the 32kHz Oscillator, and the pins are initialized to PG0 = 1, PG1 = 1, and
PG2 = 0 asynchronously when a reset condition becomes active, even if the clock is not running. PG3
and PG4 are oscillator pins.
Related Links
Alternate Functions of Port G on page 110
6.1.10. RESET
Reset input. A low level on this pin for longer than the minimum pulse length will generate a reset, even if
the clock is not running. The minimum pulse length is given in System and Reset Characteristics. Shorter
pulses are not guaranteed to generate a reset.
Related Links
System and Reset Characteristics on page 418
Atmel ATmega64A [DATASHEET]
Atmel-8160E-ATmega64A_Datasheet_Complete-09/2015
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