Datasheet

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ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]
2549Q–AVR–02/2014
Table of Contents
Features ....................................................................................................1
1 Pin Configurations ...................................................................................2
2 Overview ...................................................................................................5
2.1Block Diagram ...........................................................................................................5
2.2Comparison Between ATmega1281/2561 and ATmega640/1280/2560 ...................7
2.3Pin Descriptions .........................................................................................................7
3 Resources ............................................................................................... 10
4 About Code Examples ...........................................................................10
5 Data Retention ........................................................................................ 10
6 Capacitive touch sensing ......................................................................10
7 AVR CPU Core ........................................................................................11
7.1Introduction ..............................................................................................................11
7.2Architectural Overview .............................................................................................11
7.3ALU – Arithmetic Logic Unit .....................................................................................12
7.4Status Register ........................................................................................................12
7.5General Purpose Register File ................................................................................13
7.6Stack Pointer ...........................................................................................................15
7.7Instruction Execution Timing ...................................................................................16
7.8Reset and Interrupt Handling ...................................................................................17
8 AVR Memories ........................................................................................20
8.1In-System Reprogrammable Flash Program Memory .............................................20
8.2SRAM Data Memory ................................................................................................20
8.3EEPROM Data Memory ..........................................................................................22
8.4I/O Memory ..............................................................................................................26
9 External Memory Interface ....................................................................27
9.1Overview ..................................................................................................................27
9.2Register Description ................................................................................................34
9.3General Purpose registers .......................................................................................36
9.4External Memory registers .......................................................................................36
10 System Clock and Clock Options .........................................................39
10.1Overview ................................................................................................................39
10.2Clock Systems and their Distribution .....................................................................39