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ATmega329/3290/649/6490
2552H–AVR–11/06
Table of Contents
Features................................................................................................ 1
Features (Continued)........................................................................... 2
Pin Configurations............................................................................... 2
Disclaimer............................................................................................................. 3
Overview............................................................................................... 4
Block Diagram ...................................................................................................... 4
Comparison between ATmega329, ATmega3290, ATmega649 and ATmega6490
6
Pin Descriptions.................................................................................................... 6
Resources ............................................................................................ 8
About Code Examples......................................................................... 8
AVR CPU Core
..................................................................................... 9
Introduction........................................................................................................... 9
Architectural Overview.......................................................................................... 9
ALU – Arithmetic Logic Unit................................................................................ 10
AVR Status Register........................................................................................... 11
General Purpose Register File ........................................................................... 12
Stack Pointer ...................................................................................................... 13
Instruction Execution Timing............................................................................... 14
Reset and Interrupt Handling.............................................................................. 14
AVR ATmega329/3290/649/6490 Memories ..................................... 17
In-System Reprogrammable Flash Program Memory........................................ 17
SRAM Data Memory........................................................................................... 18
EEPROM Data Memory...................................................................................... 19
I/O Memory......................................................................................................... 24
System Clock and Clock Options .................................................... 25
Clock Systems and their Distribution.................................................................. 25
Clock Sources..................................................................................................... 26
Default Clock Source.......................................................................................... 26
Crystal Oscillator................................................................................................. 26
Low-frequency Crystal Oscillator........................................................................ 28
Calibrated Internal RC Oscillator........................................................................ 28
External Clock..................................................................................................... 30
Clock Output Buffer ............................................................................................ 31
Timer/Counter Oscillator..................................................................................... 31
System Clock Prescaler...................................................................................... 31
Power Management and Sleep Modes............................................. 33