Datasheet

369
7674F–AVR–09/09
ATmega164P/324P/644P
36. Table of Contents
Features ..................................................................................................... 1
1 Pin Configurations ................................................................................... 2
2 Overview ................................................................................................... 3
2.1 Block Diagram ...................................................................................................3
2.2 Comparison Between ATmega164P, ATmega324P and ATmega644P ...........4
2.3 Pin Descriptions .................................................................................................5
3 Resources ................................................................................................. 7
4 About Code Examples ............................................................................. 8
5 AVR CPU Core .......................................................................................... 9
5.1 Overview ............................................................................................................9
5.2 ALU – Arithmetic Logic Unit .............................................................................10
5.3 Status Register ................................................................................................11
5.4 General Purpose Register File ........................................................................12
5.5 Stack Pointer ...................................................................................................13
5.6 Instruction Execution Timing ...........................................................................14
5.7 Reset and Interrupt Handling ...........................................................................15
6 AVR Memories ........................................................................................ 18
6.1 Overview ..........................................................................................................18
6.2 In-System Reprogrammable Flash Program Memory .....................................18
6.3 SRAM Data Memory ........................................................................................19
6.4 EEPROM Data Memory ..................................................................................21
6.5 I/O Memory ......................................................................................................22
6.6 Register Description ........................................................................................23
7 System Clock and Clock Options ......................................................... 29
7.1 Clock Systems and their Distribution ...............................................................29
7.2 Clock Sources .................................................................................................30
7.3 Low Power Crystal Oscillator ...........................................................................32
7.4 Full Swing Crystal Oscillator ............................................................................33
7.5 Low Frequency Crystal Oscillator ....................................................................34
7.6 Calibrated Internal RC Oscillator .....................................................................36
7.7 128 kHz Internal Oscillator ..............................................................................37
7.8 External Clock .................................................................................................37