6

8285DS–AVR–06/11

ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P

2.2

Comparison Between

ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P

2.3

Pin Descriptions

2.3.1

VCC

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

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

Table 2-1.

Differences between: ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P

Device

Flash

EEPROM

RAM

MHz

ATmega165A

16Kbyte

512Bytes

1Kbyte

16

ATmega165PA

16Kbyte

512Bytes

1Kbyte

16

ATmega325A

32Kbyte

1Kbyte

2Kbyte

20

ATmega325PA

32Kbyte

1Kbyte

2Kbyte

20

ATmega3250A

32Kbytes

1Kbyte

2Kbyte

20

ATmega3250PA

32Kbyte

1Kbyte

2Kbyte

20

ATmega645A

64Kbyte

2Kbyte

4Kbyte

16

ATmega645P

64Kbyte

2Kbyte

4Kbyte

16

ATmega6450A

64Kbyte

2Kbyte

4Kbyte

20

ATmega6450P

64Kbyte

2Kbyte

4Kbyte

20