ATmega640/1280/1281/2560/2561
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 111.
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 113.
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
26 on page 58. Shorter pulses are not guaranteed to generate a reset.
Input to the inverting Oscillator amplifier and input to the internal clock operating circuit.
Output from the inverting Oscillator amplifier.
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.
This is the analog reference pin for the A/D Converter.
XTAL1
XTAL2
AVCC
AREF
Resources
A comprehensive set of development tools and application notes, and datasheets are
available for download on http://www.atmel.com/avr.
9
2549KS–AVR–01/07
ATMEL [ ATMEL CORPORATION ]
