ATmega640/1280/1281/2560/2561
2.2
Comparison Between ATmega1281/2561 and ATmega640/1280/2560
Each device in the ATmega640/1280/1281/2560/2561 family differs only in memory size and
number of pins. Table 2-1 summarizes the different configurations for the six devices.
Table 2-1.
Device
Configuration Summary
General
Purpose I/O pins
16 bits resolution
PWM channels
Serial
USARTs
ADC
Channels
Flash
64KB
EEPROM
4KB
RAM
8KB
8KB
8KB
8KB
8KB
ATmega640
86
86
54
86
54
12
12
6
4
4
2
4
2
16
16
8
ATmega1280
ATmega1281
ATmega2560
ATmega2561
128KB
128KB
256KB
256KB
4KB
4KB
4KB
12
6
16
8
4KB
2.3
Pin Descriptions
2.3.1
VCC
Digital supply voltage.
Ground.
2.3.2
2.3.3
GND
Port A (PA7..PA0)
Port A is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port A output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port A pins that are externally pulled low will source current if the pull-up
resistors are activated. The Port A pins are tri-stated when a reset condition becomes active,
even if the clock is not running.
Port
A
also serves the functions of various special features of the
ATmega640/1280/1281/2560/2561 as listed on page 78.
2.3.4
Port B (PB7..PB0)
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The
Port B output buffers have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port B pins that are externally 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 has better driving capabilities than the other ports.
Port
B
also serves the functions of various special features of the
ATmega640/1280/1281/2560/2561 as listed on page 79.
2.3.5
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 have symmetrical drive characteristics with both high sink and source
capability. As inputs, Port C pins that are externally pulled low will source current if the pull-up
7
2549LS–AVR–08/07
ATMEL [ ATMEL ]
