Datasheet
5
ATmega323(L)
1457E–11/01
pulled low will source current if the pull-up resistors are activated. The Port B pins are
tri-stated when a reset condition becomes active, even if the clock is not running.
Port B also serves the functions of various special features of the ATmega323 as listed
on page 135.
Port C (PC7..PC0) Port C is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each
bit). The Port C output buffers can sink 20 mA. As inputs, Port C pins that are externally
pulled low will source current if the pull-up resistors are activated. The Port C pins are
tri-stated when a reset condition becomes active, even if the clock is not running.
Port C also serves the functions of the JTAG interface and other special features of the
ATmega323 as listed on page 142. If the JTAG interface is enabled, the pull-up resistors
on pins PC5 (TDI), PC3 (TMS) and PC2 (TCK) will be activated even if a reset occurs.
Port D (PD7..PD0) Port D is an 8-bit bidirectional I/O port with internal pull-up resistors (selected for each
bit). The Port D output buffers can sink 20 mA. As inputs, Port D pins that are externally
pulled low will source current if the pull-up resistors are activated. The Port D pins are
tri-stated when a reset condition becomes active, even if the clock is not running.
Port D also serves the functions of various special features of the ATmega323 as listed
on page 147.
RESET
Reset input. A low level on this pin for more than 500 ns will generate a reset, even if the
clock is not running. 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 A and the A/D Converter. It should be externally
connected to VCC, even if the ADC is not used. If the ADC is used, it should be con-
nected to VCC through a low-pass filter. See page 124 for details on operation of the
ADC.
AREF AREF is the analog reference pin for the A/D Converter. For ADC operations, a voltage
in the range 2.56V to AVCC can be applied to this pin.
AGND Analog ground. If the board has a separate analog ground plane, this pin should be con-
nected to this ground plane. Otherwise, connect to GND.