8
2552K–AVR–04/11
ATmega329/3290/649/6490
2.3.9
Port G (PG5..PG0)
Port G is a 6-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 tri-stated when a reset condition becomes active,
even if the clock is not running.
Port G also serves the functions of various special features of the ATmega329/3290/649/6490
2.3.10
Port H (PH7..PH0)
Port H is a 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port H output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port H pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port H pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
Port H also serves the functions of various special features of the ATmega3290/6490 as listed
2.3.11
Port J (PJ6..PJ0)
Port J is a 7-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port J output buffers have symmetrical drive characteristics with both high sink and source capa-
bility. As inputs, Port J pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port J pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
Port J also serves the functions of various special features of the ATmega3290/6490 as listed on
2.3.12
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 Reset2.3.13
XTAL1
Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.
2.3.14
XTAL2
Output from the inverting Oscillator amplifier.
2.3.15
AVCC
AVCC is the supply voltage pin for Port F and the A/D Converter. It should be externally con-
nected to V
CC, even if the ADC is not used. If the ADC is used, it should be connected to VCC
through a low-pass filter.
2.3.16
AREF
This is the analog reference pin for the A/D Converter.