5

8272AS–AVR–01/10

164A/164PA/324A/324PA/644A/644PA/1284/1284P

2.

Overview

The ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P is a low-power CMOS 8-bit

microcontroller based on the AVR enhanced RISC architecture. By executing powerful instruc-

tions in a single clock cycle, the ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P

achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize

power consumption versus processing speed.

2.1

Block Diagram

Figure 2-1.

Block Diagram

The AVR core combines a rich instruction set with 32 general purpose working registers. All the

32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent

registers to be accessed in one single instruction executed in one clock cycle. The resulting

architecture is more code efficient while achieving throughputs up to ten times faster than

conventional CISC microcontrollers.

The ATmega164A/164PA/324A/324PA/644A/644PA/1284/1284P provide the following features:

CPU

GND

VCC

RESET

Power

Supervision

POR / BOD &

RESET

Watchdog

Oscillator

Watchdog

Timer

Oscillator

Circuits /

Clock

Generation

XTAL1

XTAL2

PORT A (8)

PORT D (8)

PD7..0

PORT C (8)

PC5..0

TWI

SPI

EEPROM

JTAG/OCD

16bit T/C 1

8bit T/C 2

8bit T/C 0

SRAM

FLASH

USART 0

Internal

Bandgap reference

Analog

Comparator

A/D

Converter

PA7..0

PORT B (8)

PB7..0

USART 1

TOSC1/PC6

TOSC2/PC7