Datasheet

7
ATmega325/3250/645/6450
2570K–AVR–04/07
current if the pull-up resistors are activated. The Port E pins are tri-stated 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
ATmega325/3250/645/6450 as listed on page 70.
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 resis-
tors on pins PF7(TDI), PF5(TMS), and PF4(TCK) will be activated even if a reset
occurs.
Port F also serves the functions of the JTAG interface.
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
ATmega325/3250/645/6450 as listed on page 70.
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 ATmega3250/6450 as
listed on page 70.
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 capability. 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 ATmega3250/6450 as
listed on page 70.
RESET
Reset input. A low level on this pin for longer than the minimum pulse length will gener-
ate a reset, even if the clock is not running. The minimum pulse length is given in Table
16 on page 40. Shorter pulses are not guaranteed to generate a reset.
XTAL1 Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.
XTAL2 Output from the inverting Oscillator amplifier.
AVCC AVCC is the supply voltage pin for Port F and the A/D Converter. It should be externally
connected to V
CC
, even if the ADC is not used. If the ADC is used, it should be con-
nected to V
CC
through a low-pass filter.