Datasheet

3
2593OS–AVR–02/12
ATmega644
1.1 Disclaimer
Typical values contained in this datasheet are based on simulations and characterization of
other AVR microcontrollers manufactured on the same process technology. Min and Max values
will be available after the device is characterized.
2. Overview
The ATmega644 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC
architecture. By executing powerful instructions in a single clock cycle, the ATmega644
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
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)
PC7..0
TWI
SPI
EEPROM
JTAG
8 bit T/C 0
8 bit T/C 2
16 bit T/C 1
SRAMFLASH
USART 0
Internal
Bandgap reference
Analog
Comparator
A/D
Converter
PA7..0
PORT B (8)
PB7..0