ATmega644PA datasheet(461/468 Pages) ATMEL

461 / 468 page

8152G–AVR–11/09

ATmega164PA/324PA/644PA/1284P

Table of Contents

Features ..................................................................................................... 1

Pin Configurations ................................................................................... 2

1.1Pinout - PDIP/TQFP/VQFN/QFN/MLF for ATmega164PA/324PA/644PA/1284P .....2

1.2Pinout - DRQFN for ATmega164PA/324PA/644PA ..................................................3

1.3Pinout - VFBGA for ATmega164PA/324PA/644PA ...................................................4

Overview ................................................................................................... 5

2.1Block Diagram ...........................................................................................................5

2.2Comparison Between ATmega164PA, ATmega324PA, ATmega644PA and

ATmega1284P 6

2.3Pin Descriptions ........................................................................................................7

Resources ................................................................................................. 9

About Code Examples ............................................................................. 9

Data Retention .......................................................................................... 9

AVR CPU Core ........................................................................................ 10

6.1Overview .................................................................................................................10

6.2ALU – Arithmetic Logic Unit ....................................................................................11

6.3Status Register ........................................................................................................11

6.4General Purpose Register File ................................................................................13

6.5Stack Pointer ...........................................................................................................14

6.6Instruction Execution Timing ...................................................................................15

6.7Reset and Interrupt Handling ..................................................................................16

AVR Memories ........................................................................................ 19

7.1Overview .................................................................................................................19

7.2In-System Reprogrammable Flash Program Memory .............................................19

7.3SRAM Data Memory ...............................................................................................20

7.4EEPROM Data Memory ..........................................................................................22

7.5I/O Memory ..............................................................................................................23

7.6Register Description ................................................................................................24

System Clock and Clock Options ......................................................... 30

8.1Clock Systems and their Distribution .......................................................................30

8.2Clock Sources .........................................................................................................31

8.3Low Power Crystal Oscillator ...................................................................................33

ATmega644PA Datasheet(PDF) 461 Page - ATMEL Corporation