9

ATmega640/V-1280/V-1281/V-2560/V-2561/V [SUMMARY]

2549QS–AVR–02/2014

2.3.12

Port K (PK7..PK0)

Port K serves as analog inputs to the A/D Converter.

Port K is a 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port K output buffers

have symmetrical drive characteristics with both high sink and source capability. As inputs, Port K pins that are

externally pulled low will source current if the pull-up resistors are activated. The Port K pins are tri-stated when a

reset condition becomes active, even if the clock is not running.

Port K also serves the functions of various special features of the ATmega640/1280/2560 as listed on page 92.

2.3.13

Port L (PL7..PL0)

Port L is a 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port L output buffers

have symmetrical drive characteristics with both high sink and source capability. As inputs, Port L pins that are

externally pulled low will source current if the pull-up resistors are activated. The Port L pins are tri-stated when a

reset condition becomes active, even if the clock is not running.

Port L also serves the functions of various special features of the ATmega640/1280/2560 as listed on page 94.

2.3.14

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” on page 360. Shorter

pulses are not guaranteed to generate a reset.

2.3.15

XTAL1

Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.

2.3.16

XTAL2

Output from the inverting Oscillator amplifier.

2.3.17

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 connected to V

CC through a low-pass filter.

2.3.18

AREF

This is the analog reference pin for the A/D Converter.