6
2552K–AVR–04/11
ATmega329/3290/649/6490
2.2
Comparison between ATmega329, ATmega3290, ATmega649 and ATmega6490
The ATmega329, ATmega3290, ATmega649, and ATmega6490 differs only in memory sizes,
devices.
2.3
Pin Descriptions
The following section describes the I/O-pin special functions.
2.3.1
V
CC
Digital supply voltage.
2.3.2
GND
Ground.
2.3.3
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 ATmega329/3290/649/6490
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 ATmega329/3290/649/6490
Table 2-1.
Configuration Summary
Device
Flash
EEPROM
RAM
LCD
Segments
General Purpose
I/O Pins
ATmega329
32Kbytes
1Kbytes
2Kbytes
4 x 25
54
ATmega3290
32Kbytes
1K bytes
2Kbytes
4 x 40
69
ATmega649
64Kbytes
2Kbytes
4Kbytes
4 x 25
54
ATmega6490
64Kbytes
2Kbytes
4Kbytes
4 x 40
69